A Systemic Functional Linguistic (SFL) Approach to Animal … · 2018-08-29 · 3 ACKNOWLEDGEMENTS First and foremost, I want to thank my supervisor Prof. Dr. Miriam Taverniers for

A Systemic Functional Linguistic (SFL) Approach to Animal Communication

Three Case Studies: Honeybees, Songbirds and Primates Word count: 25,393

Niels Haentjens Student number: 01403680 Supervisor: Prof. Dr. Miriam Taverniers A dissertation submitted to Ghent University in partial fulfilment of the requirements for the degree of Master of Arts in Linguistics and Literature – Language English Academic year: 2017 - 2018

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VERKLARING I.V.M. AUTEURSRECHT De auteur en de promotor(en) geven toelating deze studie als geheel voor consultatie beschikbaar te stellen voor persoonlijk gebruik. Elk ander gebruik valt onder de beperkingen van het auteursrecht, in het bijzonder met betrekking tot de verplichting de bron uitdrukkelijk te vermelden bij het aanhalen van gegevens uit deze studie. Het auteursrecht betreffende de gegevens vermeld in deze studie berust bij de promotor(en). Het auteursrecht beperkt zich tot de wijze waarop de auteur de problematiek van het onderwerp heeft benaderd en neergeschreven. De auteur respecteert daarbij het oorspronkelijk auteursrecht van de individueel geciteerde studies en eventueel bijhorende documentatie, zoals tabellen en figuren.

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ACKNOWLEDGEMENTS First and foremost, I want to thank my supervisor Prof. Dr. Miriam Taverniers for the helpful suggestions and useful feedback on my drafts. It was during one of her lectures that I got the idea for this dissertation, i.e. applying a grammatical model to animal communication. I want to thank my friends and family for the continued support throughout the process of writing this dissertation. Also, a special thanks goes out to my parents for proofreading my drafts, correcting the spelling mistakes, and generally supporting me during my studies. Finally, I want to say that during the research for this paper I have been blown away many times by the complexity and beauty of nature. It would be a shame if we lost these amazing wonders of nature as a consequence of human’s ignorance and destructive behaviour. Animals and humans are much more alike than we sometimes assume. Maybe we could even learn a thing or two from them.

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TABLE OF CONTENTS Acknowledgements ......................................................................................................................... 3 Table of Contents ............................................................................................................................ 5 List of Figures .................................................................................................................................. 6 1. Introduction ................................................................................................................................. 7 2. Theory .......................................................................................................................................... 8

2.1. Systemic Functional Grammar ........................................................................................... 8 2.1.1. Introduction ...................................................................................................................... 8 2.1.2. Key Concepts ................................................................................................................... 8

2.2. Implementing SFG in the Field of Animal Studies .......................................................... 10 2.2.1. Why SFG? ...................................................................................................................... 10 2.2.2. Animal Communication and Cognition Studies ............................................................. 11

2.2.2.1. Key Concepts ......................................................................................................... 11 2.2.2.2. Status of Research .................................................................................................. 14 2.2.2.3. Zoosemiotics .......................................................................................................... 17

2.2.3. SFG and Animal Communication: Three Case Studies ................................................. 21 3. Case Studies: Analysis .............................................................................................................. 24

3.1. Honeybees and their Communicative Dances .................................................................. 24 3.1.1. General Introduction ...................................................................................................... 24 3.1.2. SFG Approach ................................................................................................................ 29

3.2. Songbirds and Vocal Learning .......................................................................................... 34 3.2.1. General Introduction ...................................................................................................... 34

3.2.1.1. Starlings ................................................................................................................. 36 3.2.1.2. Chaffinches ............................................................................................................ 38 3.2.1.3. Zebra Finches ......................................................................................................... 41

3.2.2. SFG Approach ................................................................................................................ 43 3.3. Primate Vocalizations and Gestures ................................................................................. 47

3.3.1. General Introduction ...................................................................................................... 47 3.3.1.1. Vocal Communication ........................................................................................... 50 3.3.1.2. Gestural Communication ....................................................................................... 53

3.3.2. SFG Approach ................................................................................................................ 58 4. Discussion .................................................................................................................................. 63 5. Conclusion ................................................................................................................................. 66 List of References .......................................................................................................................... 67

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LIST OF FIGURES Figure 1: Visual representation of the concept of ‘stratification’ (based on Halliday 1985 and Butt et al. 2000) Figure 2: Visual representation of ‘stratification’ applied to general animal communication Figure 3: The honeybee’s ‘waggle dance’ (left) and ‘round dance’ (right) Figure 4: Four examples of how the direction of the waggle dance is relative to the sun Figure 5: Stratification applied to the ‘grammar’ of the honeybee’s ‘waggle dance’ Figure 6: Stratification applied to the general communicative system of honeybees Figure 7: Stratification applied to the general communicative system of songbirds Figure 8: Schematic representation of the relationship between ‘meaning’ and ‘vocalizations’ in starlings Figure 9: Schematic representation of the relationship between ‘meaning’ and ‘vocalizations’ in chaffinches Figure 10: Schematic representation of the relationship between ‘meaning’ and ‘vocalizations’ in zebra finches Figure 11: schematic representation of the relationship between ‘meaning’ and ‘vocalizations’, and the influence of context in vervet monkeys Figure 12: schematic representation of the relationship between ‘meaning’ and ‘vocalizations’, and the influence of context in Diana monkeys Figure 13: Stratification applied to the gestural communicative system of chimpanzees and bonobos

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1. INTRODUCTION Questions whether animals have the cognitive abilities to produce meaningful communicative actions and whether animals have a ‘language’, have been the topic of discussion for centuries. Nowadays only few people will deny that animals of all kinds indeed display a lot of interesting communicative features, yet also few people will claim that animals communicate in a human-like way. The amount of literature that has been written on the relationship between humans and animals is large, and, fortunately, still growing. The aim of this paper is to add something new to this field of study by interpreting the existing data and research from a functional linguistic perspective.

This paper is mainly concerned with the question to what degree it is possible to apply certain concepts from Systemic Functional Linguistics (SFL), such as ‘stratification’, ‘metafunctions’, and the importance of ‘context’, to three different forms of animal communication, and how this can contribute to a better understanding of how both human and non-human forms of communication function. I will start with a general theoretical introduction on what Systemic Functional Grammar (SFG), the grammatical model within SFL, exactly is, followed by an introduction to and an overview of the current state of research within the field of Animal Communication and Cognition Studies. Next, I will analyse three different case studies, i.e. honeybees, songbirds, and primates, with regard to their communication systems and how these can be interpreted from an SFG approach. Finally, I will briefly discuss my findings.

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2. THEORY

2.1. SYSTEMIC FUNCTIONAL GRAMMAR

2.1.1. Introduction Systemic Functional Grammar (SFG) is a grammatical model of language, which is situated in the field of functional linguistics. The model was first introduced and developed by M.A.K. Halliday in the 1950s. The term ‘systemic’ refers to the “theory of meaning as choice, by which a language, or any other semiotic system, is interpreted as networks of interlocking options” (Halliday 1985); “systemic theory, [...] is comprehensive: it is concerned with language in its entirety, so that whatever is said about one aspect is to be understood always with reference to the total picture” (Halliday 2004: 19). The term ‘functional’ refers to how the structure of the language system is interpreted: i.e. how language functions within specific contexts, how (as a consequence) “fundamental components of meaning” arise, and, finally, “how each element is explained by reference to the complete linguistic system” (Halliday 1985). Many scholars have revised and elaborated on this grammatical model and it has become very rich and complex since its commencement. Consequently, summarising the model in its entirety would be an impossible task to undertake. However, for the sake of the present research, it is of crucial importance to explain and discuss some of the key concepts of this model in further detail.

2.1.2. Key Concepts The first concept is that of ‘stratification’. Halliday acknowledges that language is a complex semiotic system, consisting of various levels, or ‘strata’. These levels can be represented as co-tangential circles (see Figure 1). The smallest circle comprises the modes of ‘expression’, such as phonology (and phonetics on an even smaller level) and graphology. These are systems of producing sound, gestures, or writing. The next level is that of ‘content’, which is split into two separate circles: ‘semantics’, the system of meanings, and ‘lexicogrammar’, the system of wordings (which in its turn can be split up in ‘morphology’ and ‘syntax’). Halliday also refers to them as “two poles of a single continuum” and mentions that “[t]his is what allows the meaning potential of a language to expand, more or less indefinitely” (2004: 24). All the previous levels are comprised in an even larger circle, which represents ‘context’. Other scholars have elaborated on this extra-linguistic notion of ‘context’, and made a distinction between an inner ‘context of

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situation’ and an outer ‘context of culture’ (Butt et al. 2000). Finally, it should be mentioned that there is a relationship between these strata, called ‘realisation’ (Halliday 1985; Butt et al. 2000), which is conventionally represented in SFG by a downward slanting arrow ( ) (Taverniers 2011).

Figure 1: Visual representation of the concept of ‘stratification’ (based on Halliday 1985 and Butt et al. 2000)

A concrete and practical example to further explain the concept of stratification is the situation where a man calls his wife at night to let her know that he will be late for dinner. The extra-linguistic context of culture in this case would be that in western culture there is a stereotypical image of the man who works and the woman who prepares dinner. The context of situation, on the other hand, would be determined by the fact that he is making a phone call and that both persons might be stressed, and by the location they are both in at that moment. On the level of content, the semantics would convey the actual meaning of the wordings of his message on the phone (the fact that he will be late), and the level of lexicogrammar allows us to analyse the meaning in terms of participants, processes, and circumstances, or in terms of subjects, objects, verbs, adverbials, etc. On the smallest level, that of the actual expression, we could analyse his message as a string of meaningful phonemes with a particular intonation contour. As this example illustrates, the stratification model allows for an analysis of every level on its own, but it also allows for a more complete image of what language is and how its different strata interact with each other.

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Another key concept that is worth mentioning here is that of the three fundamental components of meaning recognized in SFL, which are called ‘metafunctions’: the ideational, the interpersonal, and the textual metafunction. Halliday explains: “the systemic analysis shows that functionality is intrinsic to language [...]. Language is as it is because of the functions in which it has evolved in the human species. The term ‘metafunction’ was adopted to suggest that function was an integral component within the overall theory” (2004: 31). In short, I will give an overview of the three metafunctions, based on the writings of Halliday and Butt et al.

Firstly, the ideational metafunction can be split up into two parts: an experiential metafunction, which is used to express ideas (in an abstract sense) and experiences (in a more concrete sense), and a logical metafunction, which shows the relationship between the ideas and the experiences. The experiential metafunction is described by means of functional constituents, such as event types, participants taking a role in the events, types of things, etc.; the logical metafunction is encoded by means of conjunctions or punctuation. Secondly, the interpersonal metafunction is concerned with interaction on the one hand, and the position of the speaker towards the message on the other hand. Halliday suggests that the name was chosen to indicate “that it is both interactive and personal” (2004: 30). Interpersonal meanings are expressed for example through mood and modality, and through evaluative lexis. Finally, the textual metafunction organizes the previous two metafunctions into a coherent whole, by means of concepts like ‘cohesion’, ‘texture’ and ‘theme-rheme’. It is also important to mention that ‘text’ is defined as “a piece of language in use” (Butt et al. 2000), which means that it can be either written or spoken.

2.2. IMPLEMENTING SFG IN THE FIELD OF ANIMAL STUDIES

2.2.1. Why SFG? The main focus of research within the field of Systemic Functional Linguistics has always been human communication. On several occasions Halliday emphasizes that SFG is concerned with “natural, human, adult, verbal language” (2004: 20) and that “language does [...] construe human experience” (29). It is clear to the readers that language is indeed uniquely human, and that SFG was developed to describe human language and human communication. However, it is also true that there are other forms of communication (auditory, visual, electrical, chemical, etc.) known within the world of animal communication. Although none of those forms of communication are as rich and complex as human language, this does not infer that those communication systems could or should not be examined from a linguistic point of view.

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In my opinion, the SFG framework shows a lot of interesting opportunities in the field of animal communication studies, exactly because of its functional approach. The concepts mentioned in the section above (stratification, the importance of context, metafunctions) are to some extent also applicable to forms of animal communication. At the end of the next section I will further elaborate on why this grammatical model is interesting for non-human forms of communication, and how SFG might fit in within the previous research in animal communication and cognition studies. 2.2.2. Animal Communication and Cognition Studies 2.2.2.1. Key Concepts It is important to correctly define some of the key concepts and terms that are commonly used in the field of animal communication and cognition. Fischer (2012) defines communication by summarising a number of other studies. The definition is threefold: communication involves the “use of signals” and incorporates “at least a signaller and a receiver” (or a ‘sender’ and a ‘receiver’); communication can be characterised as “interaction with signals”; or as a “network”, since “most communicative interactions do not only involve two individuals but rather several subjects” (2012: 152).

With regard to defining the concept of ‘signal’, Fischer struggles with distinguishing the term correctly from ‘cues’ and ‘coercion’. After criticising the adaptationist approach, she agrees with the view proposed by Scott-Phillips, citing him: “[signals are] any act or structure that (a) affects the behavior of other organisms, (b) evolved because of those effects, and (c) which is effective because the effect (the response) has evolved to be affected by the act or structure” (153). Fischer also mentions the more linguistic concept of ‘referential signalling’, which she defines as a combination of “production specificity on the side of the sender and differential responses on the side of the listener”. These responses are “indispensable to infer whether or not animals attribute differential ‘meaning’” (159) and in most cases they are context-specific, for example in rhesus monkey screams (160).

The key component that is transferred between a sender and a receiver is ‘information’. Fischer also elaborates on the concepts of ‘information’ and ‘information transmission’, and summarizes the debate on whether both sides of the interaction have to benefit from that exchange of information (155). Marler (1961) gives some further explanations of different types of information. ‘Sexual information’ is “associated with reproduction” and normally “evoked by members of the opposite sex when in the appropriate physiological condition” (1961: 260).

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Regarding ‘individual information’, the author states: “[t]he transfer of individual information by a signal is implied whenever the response is normally only evoked, or most readily evoked, by the particular individual emitting the signal” (261). The two final types of information mentioned in this article, ‘motivational’ and ‘environmental’ information, are hard to distinguish from one another. The transmission of ‘motivational information’ may be inferred “if the response given is appropriate to a particular motivational state of the signaller” (262); for example, the readiness of the signaller to feed, fight or copulate. The transmission of ‘environmental information’ is inferred “if the response it evokes is appropriate to some characteristics of the environment of the signaller at the moment or in the immediate past” (264). The best-known example of this type of exchange of environmental information is probably the dance of the honeybee (265). Environmental information is common in human communication as well, and the author points out that, using the terminology of the famous linguist Charles Hockett, the typical human characteristic of talking about our environment (even extended over time), which is called ‘displacement’, also occurs in non-human forms of communication. Again, the most famous example is the honeybee dance (266).

It is important for the rest of this paper to discuss some other features that are typical of human language. Hockett (1959) indeed described some of these what he called ‘design features’. A first one, as already mentioned above, is ‘displacement’, which is essentially being able to communicate about things that are not readily available in time or in space. Another one is the ‘duality of patterning’, which Hockett describes as a “set of conventions in terms of minimum meaningless but differentiating ingredients (“Emphasis author”)” (1959: 33). For example, in human languages these smallest, but meaningful ingredients on the level of expression are called ‘phonemes’. The fact that a linguistic structure can be broken up into smaller parts is also called ‘discreteness’. ‘Productivity’ is the ability to “build a new utterance out of parts that have occurred in previous utterances, putting them together by pattern familiar from previous experience” (33-34). A final feature is that of ‘arbitrariness’, and it is probably the one ‘design feature’ that is the most unique to humans. This concept entails the idea that there is an arbitrary relationship between a concept (e.g. a dog) and its equivalent in a particular language (the word ‘dog’ in English) (34). This arbitrary relationship is true for almost all words, with the exception of onomatopoeia and other sound symbolic elements. Swiss linguist and semiotician De Saussure used this concept of what he called ‘signified’ and ‘signifier’ as the cornerstone of his theories. Also, the concept of a ‘symbol’, which is a sign, relationship, or an idea that signifies or is understood in a specific way that allows for more abstract reasoning, is related to these typically human features.

In animal communication and cognition studies, other terms that should be distinguished from each other are ‘message’ and its ‘meaning’. The ‘message’ is “the variation in signal structure (or usage) that is related to some aspect of the signaler or the context of signaling”,

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while the ‘meaning’ is “generated by the receiver, who processes and interprets the signal, and chooses the appropriate response in the light of all the available evidence (i.e., contextual cues)” (Fischer 2012: 158). Since the meaning of a message is often indirectly inferred from the response, the author then further distinguishes ‘meaning’ from ‘response’ by giving an example of vervet monkey alarm calls, among other examples. She explains that the meaning of the call does not change, but that the following response varies based on the type of the call and on the contextual information surrounding it. Thus, she shows that a response in such a case is highly context-dependent.

Wheeler et al. (2012) also point out the importance of context. The authors give an overview of some examples where contextual cues play a large role, such as honeybees, songbirds and primates (2012: 193), and add that the importance of context might provide “a possible tie between animal communication systems and human language” (194).

Scott-Phillips (2015) elaborates on the meaning of ‘meaning’ in animal and human communication, and the relationship between them. The author refers to the philosopher Paul Grice, who made a distinction between ‘natural’ and ‘non-natural’ meaning. Natural meaning is intuitive and “describes stable relationships between two things in the world, where one reliably predicts the other” (2015: 802), a simple example being that a sudden noise ‘means’ danger. Non-natural meaning, on the other hand, is more complex and is defined by three criteria: firstly, that “the signaller must intend to achieve in the audience a particular response”; secondly, that “the audience must recognise that the speaker has this intention”; and thirdly, that “the listener should recognise the speaker’s intention, and the listener should grasp the intended meaning at least in part because he recognises the speaker’s intention” (ibid.). The key message in this summary is that meaning is “auto-deictic, [meaning that] stimuli that have non-natural meaning point to the very intentions that triggered their production in the first place” and that it is “overtly intentional” (802-803). Human language is mostly a conventionalized code, based on this powerful system of non-natural meaning, while ‘meaning’ in animal communication studies much more often refers to the simple effect of a signal, for example in birdsong, which is ‘natural’ and ‘intuitive’, rather than ‘non-natural’ in the Gricean sense (803). In the interest of inter- and multidisciplinary study, this is an important distinction to make, especially when dealing with cross-species comparison.

Finally, some remarks on the notion of ‘imitation’, the copying of behaviour. Zentall (2006) gives an overview of definitions, evidence and imitation mechanisms. He points out the importance of imitation in the process of social learning and even suggests a more appropriate name for humans, namely “homo imitans” (2006: 335), since imitation is one of the most underrated learning abilities. Summarizing this article in its entirety would lead us too far, but I want to mention one specific example the author gives of non-imitational learning in songbirds,

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or vocal mimicry, when they learn regional dialects. He points out that the acquisition of the birdsong dialect is a special case for three reasons:

“First, although it is learned, bird song is a variation on a species-typical behavior and thus, is relatively constrained. Second, according to Heyes (1994), in the acquisition of bird song, components of the matching behavior occur by chance, and these components increase in frequency because they are intrinsically rewarding. Heyes refers to such behavior as copying rather than imitation. But finally, and most importantly, bird song takes place in the auditory modality. A characteristic of auditory events is that the stimulus produced by the demonstrator and that produced by the “observer” can be a close match, not only to a third party (i.e., the experimenter) but also to the observer.” (342)

He adds that this kind of behaviour can also be applied to visual imitation (a change in perspective), but that it is usually classified as ‘affordance learning’ (ibid.). Other forms of ‘real’ imitation include gestural imitation (in chimpanzees, orang-utans, and parrots), sequence imitation (including mirror neurons and social mirroring), generalized imitation (the ‘do-as-I-do’ concept in higher primates), goal emulation (trying to reproduce specific results), and many more (344-347). For an evolutionary perspective on the concept of imitation and social learning, I would like to refer to an article written by Caldwell and Whiten (2002).

2.2.2.2. Status of Research Already in the 18th century, English philosopher David Hume wrote a short essay ‘Of the Reason of Animals’, which starts as follows:

“Next to the ridicule of denying an evident truth, is that of taking much pains to defend it; and no truth appears to me more evident, than that the beasts are endowed with thought and reason as well as men. The arguments are in this case so obvious, that they never escape the most stupid and ignorant.” (Hume 1738: 31)

Although Hume’s claim sounds quite strong, in the rest of his essay he adds nuances on several animal related concepts, such as ‘instinct’ and ‘experience’, and he concludes that animals have some sort of reason, but by no means the same as humans.

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Nowadays only few people will deny the existence of complex forms of communication in non-humans. This relatively new field of the study of non-human forms of communication and cognition has developed through decades of extensive research, and is situated at the intersection point of multiple branches of science: (evolutionary) biology on the one hand, and ethology, cognitive science, and linguistics on the other hand. Extensive research throughout the last centuries, and more specifically in the last hundred years, shows clear evidence of consciousness, intelligence, and ability to communicate in animals to various degrees, and over multiple species (which evolved independently of each other).

An important recent discovery, included in “New evidence of animal consciousness” by Griffin and Speck (2004), is the existence of ‘explicit learning’, meaning that information can be recalled and reported, as opposed to ‘implicit learning’, which entails the change in behaviour but the inability to report it because the subject is unaware of the stimuli. Explicit learning consequently results in explicit (or declarative) memory, which was thought to be absent in non-humans, but this idea is being challenged by discoveries of the versatility of animal communication (2004: 10). Episodic memory, which encapsulates the “[m]emories of past events that include awareness of oneself perceiving the event on some remembered occasion” (10) and autonoetic consciousness were always considered to be uniquely human, but new experiments with scrub jays and dolphins lead to new debates about the level of awareness of some animals. Although several studies (with monkeys, for example) point towards a conscious memory, the authors indicate that the major problem with these concepts of ‘metamemory’ and ‘metacognition’ is that it seems to be impossible to know via experiments to what degree this human mentality exists in animals.

In the same article by Griffin and Speck (2004) the use and the making of tools is also mentioned. Tool usage requires short-term planning and adaption to behaviour (2004: 12), and it is found in a number of animals, such as higher primates, elephants and birds. The most remarkable examples of tool usage and manufacture can be found in New Caledonian crows. Experiments have shown that they use tubes, wire, sticks, and twigs, of which they can strip off the leaves, cut the material, and even bend it in the shape of a hook to probe cavities for food (12).

Looking from an evolutionary point of view, Plotnik and Clayton (2015) investigate the distance between evolutionary lineages and how it relates to the ‘convergent cognitive evolution’. They distinguish physical cognition from social cognition, i.e. competition, cooperation, and social learning (2015: 30-32). The authors regard tool use as a form of physical cognition and technical intelligence, and point out that the “tool-use repertoire differs among species” (34). Elephants use sticks to scratch, dolphins use sponges as foraging tools, and octopuses use coconut-shell halves as shelter, but the most exciting examples of complex tool use can be found in higher primates (such as gorillas and chimpanzees) and corvids. As opposed to technical

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intelligence, there are also examples of social intelligence. This includes ‘perspective taking’, which in its turn requires spatial memory and episodic-like memory, ‘cue following’, and ‘cooperation’ (sometimes referred to as ‘reciprocal altruism’). All these forms can be found in higher primates and corvids to some degree, and even in other lower primates (such as rhesus monkeys and capuchin monkeys) and other birds (such as African grey parrots and jackdaws) (Plotnik and Clayton 2015).

With regard to cognition, Wheeler et al. (2012) point out the contrasting ideas of a non-informational view on animal communication, which proposes that “signalers manipulate receivers to behave in ways that benefit the signaler rather than the receiver” (2012: 189), versus the informational view, which proposes that “signalers evolve signals that change the behavior of receivers in ways that benefit the signalers, but adds the assumption that receiver response behavior evolves to benefit receiver fitness” (ibid.). Many forms of animal communication, such as the honeybee waggle dance, alarm calls and food calls in monkeys, etc. have proven to be interpreted in favour of the informational view. The authors also state that “arguably the most complex communication systems found in nonhuman animals are seen in social insects” (2012: 191), but they add that, although social insects have a relatively simple nervous system, the complexity of their communication system is higher than some animals with more complex nervous systems. In other words, a high level of communication does not always entail a high level of cognition. The best example of a complex form of communication in a social insect is probably that of the honeybee waggle dance. Research shows that bees show signs of human language-like features, such as displacement and “functional reference” (2012: 192), and that they have several advanced cognitive abilities: ‘concepts of sameness and difference’, ‘numerical abilities’ and ‘sophisticated spatial memory’. On the other hand, though, their cognitive abilities are limited: “they are not claimed, for example, to have episodic memory or theory of mind” (ibid.).

To conclude this section of evidence of animal cognition and its relation to communication, it is important to mention recent discoveries on signalling. Smith (1991) elaborates on signalling and responding to signalling in the context of animal cognition. In general terms, signalling is making information available. In the article the author gives a number of different insights in animal signalling. Firstly, selective signalling, which refers to the flexibility to choose from a repertoire of signals, can be found in, for example, parrots (1991: 281), and in the alarm calls of male domestic fowl (283). Secondly, the existence of symbols or “symbolic signalling” (287) has been rejected by many ethologists until the discoveries of the honeybees and their dance. The author remains sceptical towards the concept of “symbols” in animal cognition studies, but he does not entirely dismiss the idea, stating that “[s]ymbolic signalling has been shown over and again by demonstration of signals with behavioral referents” (ibid.). With regard to responding to signals, as opposed to producing signals, the author states

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that animal minds might work in a human-like fashion: i.e. building a mental scenario based on expectations and predictions (295). Smith concludes that responding to signals is highly dependent on context (297). 2.2.2.3. Zoosemiotics In 1963 the term ‘zoosemiotics’, being the semiotic study of messages and signals received and given off by animals, was coined by Thomas Sebeok. This subfield of semiotics is different from what we know semiotics to be in a human context in that way that it excludes “man’s language and his secondary, language-derived semiotic systems, such as sign language or Morse code” (Sebeok 1990: 87). Communication within animals can be divided in two varieties: ‘intraspecific communication’ and ‘interspecific communication’. The first refers to the “devices at the disposal of an animal that link it to every other member of its own species, and all others to it” (87); examples of that are lip curling, tail signalling, etc., and various other types of exchange of information about location, sex, or identity. The latter, in its turn, refers to the additional capability of code-switching between individuals. Typical examples of this kind of communication are found in situations where there is a mutual advantage. For example, the honey guide bird, which wants to feed on the wax of the honey combs but cannot break open a beehive, has developed a specific call to indicate the position of a beehive to a willing human being, who can then break open the hive to consume the honey, while the bird can feed on the wax (89). With regard to species-specific languages and its relation to human language, however, Sebeok formulates it as follows:

“In brief, each kind of animal has at its command a repertoire of signs that forms a system unique to it or is, in biological parlance, species-specific. Language is a species-specific trait of man; it is therefore counterproductive and misleading to ascribe language to any other animal, except, perhaps, metaphorically.” (88)

Sebeok further investigates the different types of human-animal contact and he distinguishes and lists eight different types, ranging from ‘man as a despoiler and parasite’ to ‘man as an inanimate object, conspecific, or domesticator’ (89). The author ends with the question which domains and topics should be further explored, and whether one should concentrate on only one of these topics, or a combination of those. These topics of research can be summarised in short as: How are messages formulated and encoded? How is a message transmitted? How does the receiving

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animal decode and interpret the message? What does the total repertoire look like? What are the properties of the code? What is the influence of context? (92-93).

Busnel (1969), another scholar in the same field, discusses the different waves of studies (from ‘analytical’ and ‘naturalistic’ to ‘psychophysiological’) and also elaborates on the notion of ‘zoosemiotics’ (on the study of acoustic communication, in particular). Among other topics, she discusses the limits and goals of zoosemiotics, and she points out that in the study of animal communication the typical diagrams or schemes that illustrate the type of message, the type of code, the type of channel, etc., should include an observer (1969: 32). This also shows the somewhat ambiguous relationship between the fields of human and animal communication.

The question of what the relationship between animals and humans exactly is, has been a controversial topic for many decades. Ingold (1988) states that, although he endorses the view that the capacity for symbolic thought, which is based in the faculty of language, is unique to Homo Sapiens, “for the most part human conduct does not differ all that substantially from the conduct of non-human animals” (1988: 359). Further on, the author makes some remarks that are rather questionable:

“The words of a language, unlike the components of a communication system like the honeybees’ dance, function primarily as symbols rather than signs. This means that their reference is to the internal world of concepts rather than the external world of objects. Attending to concepts, moreover, is what we call thinking. Thus language is, first and foremost, an instrument of thought (“Emphasis author”), and not just a means for the outward expression or broadcasting of thoughts that are somehow already there, but which – in the absence of a broadcasting medium – would remain private, known only to the subject. [...] However, we cannot grasp the animals’ thoughts simply by learning and practising their communicatory mode, because the animals have no thoughts, as such, to grasp (“Emphasis author”).” (369)

I have to agree with most of the observations, but the statement that ‘animals have no thoughts’ is a gross oversimplification and the statement that language is merely ‘an instrument of thought’ is too anthropocentric, in my opinion, since it implies that having the cognitive abilities to think is unique to humans. Marler (1961) also critiques this anthropocentric approach (in both psychology and linguistics), in the sense that it leads to bias and prejudice. He also states that the “[i]nclusion of both signs and language [...] ensures from the outset that studies of communication systems shall not be restricted to the languages of man” (1961: 253).

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When departing from the anthropocentric approach, we must come to the understanding that “communication systems are far more varied than ‘language’ systems in the classical sense, making use of a wide variety of channels; e.g., auditory, visual, tactile, olfactory, thermal, and electrical gradients” (Moles 1969: 138) and that “[l]anguages form only a small subclass of the class of all communication systems” (1969: 139). Human language, which Fröhlich (2017) describes as “an abstract symbolic code to share information directly” and as “undoubtedly unique with regard to the complexity of underlying semantic and syntactic structures” (2017: 201), as a whole seems to be unique to humans. There is evidence, however, that many critical features and separate components of language are shared with other animals. What follows here is a short summary of distinctive human features (see also Hockett (1959)) in animal communication, which is by no means complete: the existence of ‘traditions’ and ‘dialects’ in, for example, alarm calls of vervet monkeys, ‘meta-communication’, ‘capacity for innovation’ and ‘capacity for deceptive manipulation’ in songbirds, ‘double articulation’ and ‘simple syntax’ in capuchin and rhesus monkeys, ‘dialogue’ and ‘arbitrariness’ in honeybees (Lestel 2002: 382-383). Marler (1961) points out yet another typically human feature, namely the ‘divisibility of signals’ in, for example, the facial expression of chimpanzees, and the basic motifs in songs and alarm calls of certain songbirds (1961: 270).

Next to the anthropocentric approach, we must also be careful not to fall into the trap of the glottocentric approach. Ramsay (1969) eloquently phrases it as follows:

“In the past, investigations of animal communication have been preponderantly glottocentric: thus the properties of language have been imposed on animal signaling systems. For instance, of the variety of channels employed by living organisms, only the auditory and visual have received extensive study. In particular, the communicative functions of these systems have been stressed; other functions were overlooked. Language is only a particular instance of animal communication, although a unique one, and languages are a small sub-class of the larger class of communication systems.” (1969: 181)

Language is by no means the only way in which we communicate, taking into account body posture, hand gestures, and eye movement. Yet, some scholars, such as Wheeler et al. (2012), challenge the assertion that typically human linguistic features such as recursion, left-right branching, and embedding (which are syntactic devices related to sentence and word structure), are also apparent in animals. The authors refer to the experiments, conducted by Gentner et al., on the ability of starlings to distinguish sequences (2012: 197).

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Most scholars promote a multimodal or multichannel approach. Sebeok (1990) already mentioned that we “tend to think of the vocal-auditory link as the paramount channel”, while actually “the use of sound in the wider scheme of biological existence is rather uncommon: the overwhelming majority of animals are both deaf and dumb” (1990: 90). Besides the optical and acoustic channel, there are other channels (or modes) through which information can be transmitted. We must, therefore, abandon the traditional notion of ‘the five senses’ and extend it by taking into account tactile signs, electric signs and even chemicals signs, such as smells or pheromones. Of course, a combination of those may occur in a specific hierarchy, which Sebeok illustrates with the social dynamics of a wolf pack (92).

Fröhlich (2017) also critiques the lack of a holistic view and points out that “multimodal communication refers to the integration of at least two out of three communicative ‘modalities’ – vocalization (perceived acoustically), gesture (perceived visually, acoustically and/or tactilely), and facial expression (perceived visually)” (2017: 203). The author mainly investigates in her article the concepts of ‘turn-taking’ and ‘conversation-analytic tools’. She concludes that the combination of two perspectives on communication (turn-taking and multimodality) could enhance our understanding of animal signaling, and that “[t]hrough understanding turn-taking across different sensory modalities in animals we might be able to advance the bridging of the gap between human and nonhuman communication research” (207).

A final remark worth mentioning here regarding the topic of zoosemiotics is the idea of the “human being as a Universal Interlocutor” (Lestel 2002: 391). Lestel (2002: 391-395) points out that the main field of study should be “pure”, in the sense that animals (and consequently their behaviour) are perturbed by humans, and thus influenced by human intervention. He uses ‘perturbed’ in a pejorative sense, but also remarks that “with the help of language humans can develop a sophisticated knowledge of non-human communications and thus gain access to their meaning” (395). One example that the author gives is the essential role of human language in the process of language acquisition in chimpanzees. Experiments have shown that chimpanzees can communicate via symbols and sign language, yet it is humans who have imposed these systems on them (394). Even though human and animal semiotic systems are by no means the same, “[l]anguage enables humans to become universal interlocutors, with all living beings” (ibid.). This is a very interesting hypothesis for linguists, psychologists and ethologists to investigate to what degree we can communicate with other species via the Socratic method to stimulate and extract a possible underlying and dormant capability of complex communication.

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2.2.3. SFG and Animal Communication: Three Case Studies The previous section serves mostly as an introduction to the field of animal communication and cognition studies, showing how it overlaps with other fields of study, such as psychology, ethology, and most importantly for this paper, linguistics. Most notably, a large part of the modern academic world that is concerned with animal communication focuses on the importance of context. Within the SFG framework, one could argue that the context (the outer circle) has an influence on the meaning (the semantics) of animal calls, signals, and gestures of all kinds (the lexicogrammar). The context of culture is largely species-specific and is dependent on the environment an animal normally lives in (the jungle, the woods, the grasslands, or under the sea). The context of situation is in its turn largely dependent on both the species and the environment, because naturally they determine the situational circumstances. At this level one should also ask some important questions like: what is the number of participants? What is the role of the participants? Are there humans involved, and if so, what is their role? On the next level, that of semantics, we can analyse the meaning of the message in terms of the purpose of the sender, the effect it causes on the receiver and its environment, and whether there might be a mutual advantage. On the level of expression, not many animals have developed a sufficiently developed cognitive structure to distinguish between ‘lexicogrammar’ and ‘phonology’. Therefore, I propose to reduce the level of expression to one inner circle, representing whatever means of communication an animal uses and how that particular sign functions: e.g. visual-auditory signs, such as calls, screams, songs, gestures, grunts, or other utterances; or non-visual-auditory signs, such as smells, electric signals, etc. Again, these are quite species-specific. Interestingly, the merging of the two inner circles is compatible with what the linguist Hockett (1959) implies with his concept of ‘duality of patterning’, since it is generally agreed upon that animals do not use communication systems that make use of a set of conventional meaningful component to build larger units of meaning. See Figure 2 for a visual representation of the stratification model, generally applied to all forms of communication.

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Figure 2: Visual representation of ‘stratification’ applied to general animal communication With regard to the three ‘metafunctions’, the applicability of these concepts again depends on the cognitive abilities of different animals. Within the ideational metafunction, naturally concrete signals and other utterances are easier to describe and analyse (in terms of their nature and structure) than inner thoughts or instincts. The interpersonal metafunction, in its turn, might need to be changed to more a appropriate term, such as ‘interspecific’ or ‘interindividual’, since we are not dealing with persons, but rather with individuals of a specific species. Also, since this metafunction is concerned with the notion of ‘interaction’ specifically, one has to take into account the position of the speaker in different situations. Finally, the textual metafunction can only partly be applied to animal communication, since the distinction between written and spoken communication does not really apply here. So, when dealing with animal communication, the ‘written’ part of this metafunction can be safely ignored. The other part, however, concerned with how the message is logically structured as a whole, is readily applicable to almost all kinds of communication. In higher forms of communication one could even adopt the concepts of ‘cohesion’, ‘coherence’, or ‘texture’, and apply them to the message.

In the following section I will try to apply the abovementioned concepts to three case studies. I have chosen to analyse three different animal species, namely the honeybee, a variety of songbirds, and a variety of primates. The reason why exactly these three species is threefold: firstly, these animals are generally known for their incredible communicative and cognitive abilities;

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secondly, the species all belong to different animal classes, which is necessary to avoid any evolutionary linkage; and thirdly, there is already a copious amount of literature written on these animals, which allowed me to do an in-depth analysis of both the biological and linguistic research available.

As many scholars already have pointed out, case studies only represent a small proportion of all the forms of animal communication, and I can by no means draw general conclusions by studying them. Wenner (1969) eloquently explains:

“[S]ome researchers in animal communication may study a limited number of species (or only one) and then attempt to discuss animal communication in general. Others limit themselves to a study of communication in one channel and then attempt to discuss all of animal communication with reference to what may be true for only one channel – emphasizing the use of a mode rather than the act of communication itself.” (1969: 232-233)

Furthermore, it is important not to fall into the trap of the anthropocentric or glottocentric approach, but rather will I try to do the reverse: to start from the biological data and then try to adapt and apply the SFG model in function of the available biological data extracted from a wide range of communication-oriented experiments.

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3. CASE STUDIES: ANALYSIS

3.1. HONEYBEES AND THEIR COMMUNICATIVE DANCES

3.1.1. General Introduction The first scholar to have extensively researched honeybees (Apis mellifera) and their communication was Karl von Frisch during the first half of the 20th century. He amazed the world with his ground-breaking findings, on the basis of numerous experiments with honeybees, regarding sensory experience, symbolic referencing through dances, spatial memory, displacement, etc. Throughout the 20th century some scholars have criticised his theories, but to little avail. Von Frisch’s hypotheses have been proven to be scientifically correct, and in 1973 he was rewarded the Nobel Prize for Physiology or Medicine, together with Konrad Lorenz and Nikolaas Tinbergen. Nowadays, indeed, only few will deny the wondrous characteristics that bee communication displays. Yet, it is important to emphasize that the level of complexity in communication is not always necessarily related to brain size or general cognition. On the one hand, some scholars remain sceptical towards the language-like qualities of bee waggle dances, such as Ingold (1988), who points out the inability of bees to lie and to have interactive conversations (neither among bees nor between a human and a bee). This leads him to think that there is no “intentional exchange of ideas between thinking subjects” and that “[t]he words of a language, unlike the components of a communication system like the honeybees’ dance, function primarily as symbols rather than signs” (1988: 366-369). Other scholars, on the other hand, such as Griffin and Speck (2004) come to the conclusion that bees show a versatile and complex symbolic communication system and that, based on new research evidence, bees must have some sort of consciousness and some sort of learning abilities (2004: 14-15). However, to understand the very basics of bee communication, we must return to the work of Karl von Frisch. Honeybees are social insects that live in colonies, which means that there is a clear-cut distinction between the roles that every individual plays within the beehive. There is one queen (a large fertile female), a small proportion of males (drones), and a large proportion of female working bees. The latter category is the one that needs to find and collect the nectar from flowers in the vicinity of the beehive. Consequently, these female workers need to communicate to each other about where exactly the best sources of food can be found in the area surrounding the beehive. By conducting a large number of practical and insightful experiments, von Frisch discovered the characteristics of these bees’ sensory perception (colour vision and scent transmission), and communicative dances.

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Regarding the colour sense of the honeybee, von Frisch (1950) did a number of experiments with coloured cardboards, which lead him to the conclusion that bees are ‘red-blind’. In 1927 another Professor, called A. Kühn, repeated his experiments, and confirmed von Frisch’s results, namely that “bees are red-blind, that they can distinguish other colors from all shades of gray, and that they confuse yellow with orange and green, or blue with violet” (von Frisch 1950: 8). Compared to human vision, this means that on the one hand they have a shortened vision in the red wavelength, but on the other hand extended in the ultraviolet wavelength (which is invisible to humans) (1950: 9). The communicative dances observed in bees can be distinguished in terms of two different categories: the ‘waggle dance’ and the ‘round dance’. Von Frisch showed that the distance towards the food source is what determines which dance is used. ‘Round dances’ are used when the food source is in the immediate vicinity of the beehive, or when the distance is less than 50 meters (von Frisch 1992: 144). The worker bee that found a food source within 50 meters of the beehive communicates this by dancing in repeated circles, while followed by other bees. This dancing pattern allows for passing the scent of the flower from one bee to another. Remarkably, this is also in the interest of the flowers from which the scent originates, since the pollination can only happen if a bee carries the pollen to a flower of the same kind (and consequently, the same scent). The degree of agitation in the dance indicates how large the food source is: the more agitation, the richer the food source. The ‘waggle dance’ (or ‘tail-waggle dance’), on the other hand, is used for food sources at larger distances. Von Frisch described it as follows: “[t]hey run a short distance in a straight line while wagging the abdomen very rapidly from side to side; then they make a complete 360-degree turn to the left, run straight ahead once more, turn to the right, and repeat this pattern over and over again” (von Frisch 1950: 70). See Figure 3 for a visual representation of the ‘waggle dance’ and the ‘round dance’.

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Figure 3: The honeybee’s ‘waggle dance’ (left) and ‘round dance’ (right) The ‘waggle dance’ expresses two major components of meaning: the distance and the direction towards the food source. The distance is “indicated in a rather exact manner by the number of turns in the wagging dance that are made in a given time” (von Frisch 1950: 72) and is also symbolically expressed by the time of the tail wagging: “[f]or distances of 200 to 4500 m, [the tail-wagging times] increase from about 0.5 seconds to about 4 seconds” (von Frisch 1992: 145). It should also be noted that bees do not measure these distances in terms of special extent, but rather in terms of the amount of energy they use to cover a specific distance. This means that the perception of the actual distance can be influenced by external factors, such as mountains or hill slopes, or winds and other weather conditions. The directions in which the bees perform their waggle dances are dependent on the position of the sun, and indicate to the other bees where the food source is relative to the beehive. The complexity and ingenuity of this system is, to say the least, remarkable. When a bee returns to the beehive with information on where there is a rich food source, she performs her waggle dance at such an angle that makes it clear to the other bees following her where that source is in position to the sun. Von Frisch points out that this takes place “in the darkness of the hive, on the vertical surface of the comb, as an angular deflection from the vertical” (1992: 145), which shows that bees have the remarkable cognitive ability of transposing an angle in the horizontal world to

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a different area of sense perception (the vertical comb in the beehive). This is possible because they use the force of gravity as a reference point. Von Frisch explains: “[t]hey orient the straight portion of the dance at the same angle to the force of gravity as the angle they have flown with respect to the sun during the flight from hive to feeding place” (1950: 77). See Figure 4 for a visual representation of how the direction is relative to the sun. The vertical line represents the force of gravity and the abbreviations are H: hive, S: sun, and F: food.

Figure 4: Four examples of how the direction of the waggle dance is relative to the sun Figure 4 requires some more detailed explanation. In the first example the food (F) is situated between the hive (H) and the sun (S). In such a case the bee will perform a dance straight up,

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since the force of gravity corresponds to the direction of the sun. Von Frisch supposed that this coincidence has evolutionary grounds:

“It is remarkable that the heading toward the sun (“Emphasis author’) is the direction of flight selected to correspond with an upward (“Emphasis author”) movement during the straight component of the wagging dance. One cannot believe that bees decided all at once to arrange matters thus. We may be sure that this meaningful relationship has developed gradually, like other abilities, in the course of the history of the species.” (von Frisch 1950: 78)

In the second example the food source is located 60 degrees to the left of the sun. This means that the bee will adjust her waggle dance 60 degrees to the left, relative to the force of gravity. In the third example the food source is located 90 degrees to the right of the sun, which results in a 90 degrees turn to the right, again, relative to the force of gravity. And in the final example the bee will perform her dance upside-down (180°), since the food source is in the opposite direction of the sun.

It is also remarkable that the sun does not have to be entirely visible for bees to find their way. This is mainly because of their specific colour perception, as mentioned above. Von Frisch has shown through experimentation that bees use the ultraviolet vision and the polarisation of blue in the sky to know where the sun is located, even when it is obscured by a cloud or a mountain (1950: 95). Von Frisch adds: “Thus, bees are able to perceive polarized light. The sky, which to our eyes is a uniform blue, is distinctly patterned to them. They use this extensively and, in their orientation, guide themselves not only by the sun’s position but also by the resulting polarization patterns of the blue sky” (1992: 151).

Besides indicating the direction and the distance, the communicative dance serves yet another purpose, that is, the transfer of the scent of the flower or the food source. Von Frisch also did extensive research on the scent perception of honeybees by experimenting with different types of scented boxes and fragrance oils (1950: 26-27). Anatomically, it has been shown that “the antennae of bees are densely covered by sense organs, some of which are organs of touch and others organs of smell” (30), which “can distinguish four qualities of taste (sweet, bitter, salty, and sour)” (44). The importance of scent cannot be underestimated, since it is a simple but effective means of communication. Von Frisch points out that bees do not so much differentiate flowers by colour, but rather by their unique fragrance. This has a large influence on the livelihood of the dance, since the dancers pass over the smell that adheres to their upper body. The bees that follow the dancing bee hold out their antennae towards her. She then regurgitates a droplet of nectar (which is saturated with the characteristic smell of the flower) and feeds it to the

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bees that are following her (1950: 60-61). Moreover, this ‘economy of smells’ is a key characteristic of the natural environment of the bee. Von Frisch elaborates:

“Various types of plants blossom simultaneously, producing nectar of differing concentrations. The richer and sweeter its flow, the livelier the dance of the bees that discover and visit one type of flower. The flowers with the best nectar transmit a specific fragrance which ensures that they are most sought after. Thus, in this simple fashion, traffic is regulated according to the law of supply and demand not only to benefit the bees but also to promote pollination and seed yield of plant varieties rich in nectar. A new and hitherto unknown side of the biological significance of flower fragrance is thus revealed. Its great diversity and strict species specificity communicate a truly charming scent language.” (1992: 143)

Finally, it is important to emphasize how incredible the sensory and cognitive abilities of the honeybee really are. With regard to sensory perception, we have seen that they possess an amazing chemical sense for flower fragrance on the one hand, and a visual continuum that allows for viewing patterns of polarised light in the sky on the other hand. And although this is also apparent in other insects, crayfish, octopuses and spiders, honeybees do not use it merely for navigation, but they incorporate it in their system of communication, which is unparalleled in the animal world (1992: 153). With regard to their cognitive abilities, one can only be astonished by the fact that bees have excellent memory, both diurnal and spatial, and have cognitive skills like ‘displacement’ and ‘social learning’, especially if one considers the size of their brains. 3.1.2. SFG Approach When analysing the communicative dances of honeybees, we can notice that there is an underlying structure indicating the symbolical relationship between certain actions and their corresponding meaning. In the following paragraphs, I will explain the ‘grammar’ of the communicative dances in more detail, and apply the stratification model to it.

The ‘round dance’ is performed when food is to be found in the immediate vicinity of the beehive (less than 50 meters). Von Frisch noted that “[t]he message brought by a bee as she performed the round dance seemed to be a very simple one, one that carried the meaning ‘Fly out and seek in the neighborhood of the hive’.” (1950: 56) Because of the close contact between the arriving bee and the following bees, the transfer of scent particles can be seen as a form of communication too, expressing a message like: ‘This is the smell you have to find’.

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With regard to the ‘waggle dance’, the ‘grammar’ is somewhat more complex in the sense that the dance has multiple components, which each express a specific message. The first one, the transfer of the scent, expresses a similar message to that of the round dance. Only, in this case the following bees do not only have to rely on their chemical perception, since they can extract additional and more fine-grained information on the distance they will have to traverse and on the direction in which they will have to fly.

Although the context (the position of the beehive, the position of the sun, the possibility of human intervention, the type of flower, etc.) does play a role in the communicative dance, it does not have a major influence on the fundamental building blocks of meaning. There is a clear relationship between these building blocks, or smallest components of meaning, and their specific and corresponding meaning. In this case, the smallest components of meaning are: the scent they carry, the angle in which they dance, and the tempo in which they perform the dance. These are then linked to the semantic level, each with their corresponding meaning, which the following bee can interpret. See Figure 5 for a visual representation of the stratification model applied to the ‘grammar’ of the ‘waggle dance’. The two-sided arrows do not represent opposition, but rather indicate that the concepts are linked.

Figure 5: Stratification applied to the ‘grammar’ of the honeybee’s ‘waggle dance’

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I will give a short but concrete example of how one could apply this model. If a bee wants to understand what an arriving bee is trying to communicate about a possible food source, she will follow the communicative dance. From this dance she can derive three basic components of meaning, which give her information on where to find that food source. So, when the following bee smells lavender, which scent was brought in by the bee that found the food source, she interprets and remembers this as ‘I have to find lavender’. At the same time, in the darkness of the beehive, she is interpreting the angle of the dance, relative to the force of gravity, and remembers that ‘upwards’ represents the direction of the sun. When the dancer is waggling at a 45° angle towards the right, the following bee will interpret this as ‘I have to fly at such an angle that the sun is at a 45° angle at the left of me’. Finally, the number of turns and the tempo of the waggles have to be interpreted to know how far from the beehive the food source is located. Since the dancer is performing a waggle dance, the distance must be quite large (further than 50 meters). The number of turns and the time to perform them indicates the distance to the food source. Von Frisch (1950) explains this as follows:

“At 100 meters there were 9 to 10 complete cycles of the dance within 15 seconds; at 200 meters there were 7; at 1 kilometer, 41/2; and at 6 kilometers, only 2. If we know this relation between rate of turning and distance to the food, we can tell by means of a stop watch about how far a dancing bee has flown. The bees in the hive can also understand the meaning of the dancer's rate of turning and can perceive the distance they must fly to reach the food.” (1950: 73-74)

If we regard the communicative system as a whole, and apply the stratification model to a honeybee communication system in general, it would look like Figure 6.

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Figure 6: Stratification applied to the general communicative system of honeybees Here we can see the clear relationship (the ‘realisations’) between the different levels or ‘strata’. The species-specific context is more or less fixed in the sense that social insects such as honeybees have a natural environment in which they can live and work, but the context of situation can vary between a whole range of possible situational circumstances: is the beehive located in open nature or in a humanly controlled environment? What does the immediate vicinity of the hive look like? Are there mountains, rivers or woods around? Are there predators around? What is the weather like? All these external contextual circumstances influence the inner circles of ‘Semantics’ and ‘Means of Expression’. They are closely interlinked, because every basic component from the inner circle has a one-to-one relationship of expressing meaning on the semantic level, which is functional in the specific and more general context. It is also important to note that although human intervention is important with regard to the context, it does not at all matter to the bees whether there is human intervention or not. So, in the case of communicative dances, there is by no means any moment where humans intervene as a universal interlocutor, or wake up or stimulate a dormant, more language-like communication system. It shows that these bees perform the communicative dances naturally and instinctively.

When we look at the metafunctions of honeybee communication, we notice that it is difficult to understand the exact cognitive abilities of these animals, and we do not know to what degree the ‘grammar’ of these communicative dances is instinctive or learned. The ideational

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metafunction, however, is quite well developed, since bees do seem to have imaginative spatial concepts, such as the position of a flower or the position of the sun relative to the beehive, and also possess the means to express these concepts. These components of meaning could thus be interpreted as constituents of a message, which is ordered sequentially, so that the following bees can interpret it. The interpersonal (or rather ‘interindividual’) metafunction is also very important, because the only moment that this form of communication arises, is when bees are in interaction with each other. Although there is no real conversation taking place, there is a signaller and a receiver, and consequently a transfer of meaning. The content of the message is very straightforward in the sense that it only expresses information on where food can be found, and is not at all concerned with whether the other bees have had a great day or whether the weather was nice. This brings us to the third metafunction: the textual metafunction. The mode in this case is neither spoken nor written (in the conventional sense). Although humans can conceptualise the dances visually in drawings and animations, bees do not perceive it visually since most of the time the inside of the beehive is obscured from the light outside, but rather do they perceive the dance as a combination of auditory perception (the tempo of the buzzing noise) and tactile perception (closely following another bee’s dance).

Lestel (2002), however, mentions some remarks from Sebeok’s earlier writing on bee communication, where he raised the idea “that communication by means of odours is a form of writing rather than of speech” (2002: 387). But because of the fact that the content of honeybee messages is simply communicating the location of a food source, which is not very complex in terms of content, it is not of much use to apply concepts such as ‘texture’ and ‘coherence’.

To conclude this section on honeybee communication, I will shortly summarize the analysis. The communicative dances performed by female worker bees serve the purpose of transferring information about the location of an interesting food source in the vicinity of the beehive. The dances consist of meaningful components (or constituents), which each represent a piece of information that can be interpreted by another bee. Although the system itself is amazingly complex for an insect with such a small brain, the content of the messages is rather simple. This allows for a relatively simple interpretation both in terms of metafunctions and in terms of the stratification scheme, where there seems to be a clear relationship between the level of semantics and the level of expression.

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3.2. SONGBIRDS AND VOCAL LEARNING

3.2.1. General Introduction Many species of birds display language-like features, but never all features at once. Lestel (2002) mentions some examples: dialectal variation (i.e. local, acquired characteristics passed on from one generation to the next), meta-communication in song patterns, capacity for innovation, deception (i.e. manipulating the meaning of expressions by deliberately giving alarm calls even when predators are not there; observed in blackbirds, song thrushes and chickadees), double articulation, and dialogue (2002: 382-383). As mentioned before, several bird species show remarkably high cognitive abilities, such as episodic memory in scrub jays or tool use in New Caledonian crows (Griffin and Speck 2004: 10-12). Because of the scope of this paper, however, I will limit my research to those species of birds that communicate through ‘vocal learning’, which is the ability to learn to produce and modify vocalizations. There are three avian species where ‘vocal learning’ is known to be present, which are: parrots, songbirds, and hummingbirds (Lachlan 2008: 320; Wheeler et al. 2012: 196). For this paper, I will disregard the hummingbirds (since there is a lack of sufficient scientific research on these birds); I will only briefly touch upon the parrots and then go into more detail with the songbirds. Parrots are known to be imitators, both in their natural environment and as pets in a domestic environment. New research shows evidence that African grey parrots (Psittacus erithacus) do not merely imitate because they can, but that (in interaction with humans) they can use the imitation of human words in a meaningful way (Griffin and Speck 2004: 12). In their natural environment, however, parrots use dialogue, also called ‘duetting’, for a number of reasons: it defines sex-specific roles, stimulates the pairing of mates, and determines territory maintenance and defence (Dahlin and Wright 2012: 647). There is a defined progression and even syntax apparent in the ordering of vocalizations. Dahlin and Wright (2012) found the remarkable trait in yellow-naped amazons (Amazona auropalliata) through experimentation with syntax reversal. The authors concluded that “breaking one rule of duet syntax at a time does not result in detectable loss of signal efficacy in the context of territorial intrusions” (2012: 647) and that the playback of broken syntax duets merely results in a latency to approach the ‘speaker’ (655). It should be noted that many of these studies and experiments conducted have a high rate of human intervention, or rather display the attempt of humans to intervene or extract possible means of communication out of these birds. Another example of such a study is by Kaufman et al. (2013), who researched the higher-order semantic structures in a home-raised African grey parrot. They mention that social interaction plays a big role in both the acquisition and the use of

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speech by parrots, but emphasize even more the importance of ‘context’ in their experiments. They conclude that the vocalization patterns of the specific parrot did contain global co-occurrence and that the results strongly indicate higher-order cognitive skills (2013: 789). Although the experiments were conducted in different contextual environments, additional research is necessary before definitive conclusions may be drawn. Songbirds, as opposed to parrots, show much more interesting and complex types of vocal learning and vocal communication. In his article on imitation, Zentall (2006) categorises bird song as an example of social learning, rather than a form of imitational learning. He phrases it as follows:

“Although for many species of song bird the development of species-typical song is regulated to a large extent by maturation and the seasonally fluctuating release of hormones, regional variations in the song appear to depend on the bird’s early experience with conspecifics.” (342)

With regard to these regional variations (or ‘dialects’), he points out that we are dealing with a special kind of imitation, for three reasons: firstly, because bird song is species-typical and relatively constrained; secondly, because components of matching behaviour occur by chance (and increase in frequency); and thirdly, because it takes place in the auditory modality, which is characterised by the fact that a stimulus produced by a ‘demonstrator’ and an ‘observer’ can be a close match (Zentall 2006: 342). The author also mentions that the discovery of ‘mirror neurons’ is being praised as the specific mechanism that is responsible for imitation, which the author disagrees with. He does agree with the fact that mirror neurons are active when there is a match between the demonstrator’s performance and the observer’s performance, which he explains as a special case of generalized stimulus identity learning (348-349). Wheeler et al. (2012) also mention the notion of ‘mirror neurons’ with regard to gestural theory in some monkey species, but they refer to a recent study stating that “mirror neurons have recently been shown to also exist in the song system of songbirds” (2012: 202). In the following sections I will give an overview of some general characteristics of bird song on the basis of some recent studies with regard to three particular songbirds, namely starlings (Sturnus vulgaris), chaffinches (Fringilla coelebs) and zebra finches (Taeniopygia guttata).

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3.2.1.1. Starlings As mentioned before, starlings are known to have recursion (the ability to embed larger structures into smaller structures and vice versa) in their songs, which was always considered as a typically linguistic trait of human languages. Hausberger et al. (2008) point out that according to the ‘theory of communication contract’, which in this case is applied to vocal communication, there is a certain number of rules and principles that determine the meaning of an expression. In duetting birds evidence has been found of “shared ‘agreement’ on ‘rules’” (2008: 124), and these rules vary from species to species. With regard to starling song, the authors mention that the complex vocal system is “very much subject to social influence” and “sensitive to context”, changing song types based on “the number of birds present, nest proximity, and foraging or roost situation” (125). Interestingly, the reaction of male starlings to a song from another region or dialectal population is a latency to respond less or even to fly off (126). There are two types of song that starlings use. The first one is called ‘warbling’, which consists of long, continuous series of motifs sung mostly at low intensities. When they are warbling, starlings are in an excited state and pay little attention to their surroundings. The second type is ‘whistling’, which consists of loud, discrete, and short vocalizations. While whistling, starlings leave some time in between successive whistles and pay attention to any possible response (129). Comins and Gentner (2014) point out that identification of other individuals relies heavily on singer-specific motifs, and that such a motif is a “patterned arrangement of notes” (2014: 1023). Their use is heavily dependent on the context, as Hausberger et al. (2008) explain:

“[...] male starlings do indeed change their song quantity and quality based on whether they are paired or not. Thus, removal of the female during the breeding season induces a drastic and rapid change in male song quality, with an increase in warbling song sequences (i.e., resulting in a long and melodious song), including particular elements such as high-pitched trills that decrease again after pair formation. In contrast, an increase of the typical male universal whistles (i.e., class 1 whistles; Hausberger, 1997) is observed after pair formation (Henry et al., 1994). This is in accordance with the suggestion that warbling song is important in attracting females and class 1 whistles in spacing between males (recalling to mind the loud calls of primates” (2008: 126)

It seems that there are two contextual situations possible, viz. “attraction of females or male spacing”, and thus, that the song type is involved with mate choice and the type of expected

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response from the receiver (2008: 126). The authors conclude that, concerning contextual sensitivity and rule learning, “starlings do take into account the general context” and that “they seem to have elementary ‘rules’ that all adults tend to respect in a usual context” (ibid.). Another important and somewhat related aspect is ‘turn taking’, which is a general feature of social interaction where speakers and observers change roles. In human communication a great deal of contextual flexibility is possible, based on the number of interlocutors, social status, culture, and individual history (Hausberger et al. 2008: 128-129). Starlings are very social birds (living in colonies and foraging groups), and the authors again point at the importance of social context:

“Whereas isolated birds tend to favor the production of warbling songs and have a tendency otherwise to produce only one whistle per sequence, starlings living in large colonies tend to have long sequences of whistles and only a few sequences of warbling. Our actual data indicated that a correlation existed between the number of neighbors and the tendency to whistle instead of warbling. Starlings favor songs that correspond to turn taking when confronted with neighbors in a colony. In social isolation, they instead favor a ‘self-centered continuous song.’” (130)

The learning process in young songbirds consists of a “succession of stages from subsong (a continuous unstructured song), to plastic song (an intermediate stage where the first adult elements can be detected), and to the final stage of adult song” (131). The ‘subsong’ phase can be compared to the ‘babbling’ phase in human babies, and the pattern of alternating vocalizations is learned through interaction with adults, who play the major role in song learning, as is the case with human infants and their acquisition of human language. The authors also add that both songbirds and parrots show evidence of ‘rehearsal’ and ‘solitary play’, to practice and improve their vocalizations. In the case of starlings, it is also learned how song types are embedded in context: warbling predominates in social isolation, while clear, distinct, and interspersed whistles predominate when neighbours are present in the colony (132-133). Another aspect that has to be learned is that of ‘overlap’. As expected, chicks who have not yet learned the rules of turn taking and who are still in their ‘solitary play’ phase do constantly overlap with others’ songs, but this disappears gradually after 7 to 9 months (131). The authors go much deeper into overlapping, since it seems almost unavoidable in large flocks of birds, but I will not elaborate on that here. Comins and Gentner (2014) researched the notion of ‘auditory temporal pattern learning’ and also refer to experiments they did with starlings. They found that abstract motif patterning rules could be acquired from trial-unique stimuli and that training could lead to better pattern

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generalisation (2014: 1029). It must be noted, though, that the rate of influence of humans in these types of experiments is very high, and that there is a possibility that humans interfere as a ‘universal interlocutor’. This is not necessarily bad, but it says something about the early evolutionary links between birds and humans regarding neurobiological implementation of pattern recognition rather than that it proves anything about the natural behaviour of songbirds.

3.2.1.2. Chaffinches This species of songbirds was thoroughly researched in the 1950s by ethologist Peter Marler. He found that chaffinches are monogamous and that only males (especially unmated males) perform their song (Marler 1961: 258). Each male, consequently, has a vocal repertoire of song types, often with some peculiar characteristic that makes easy identification possible, and each song “lasts about two or three seconds, to be repeated after a pause, at an average rate of 6.6 songs per minute” (Marler 1956: 83-84). The most appropriate sexual partner for an unmated female chaffinch is “an unmated male chaffinch in reproductive condition, in possession of a territory (within which nesting will take place), who is close to a location occupied by the female at the same time as she is there (“Emphasis author”)”, and she will eventually respond and approach the male chaffinch to establish a pair bond (1961: 258).

The song of the male chaffinch has two major functions, as most songbird songs do: attracting females as mates and repelling other males in terms of territorial defense (Marler 1956: 88; Lachlan 2008: 307). This is motivated by the fact that “there is a reciprocal relationship between song and sexual activity”, and that “it occurs spontaneously within the territory”, controlled by internal factors, such as sex hormones (Marler 1956: 88). Besides ‘normal’ song there are three other types of song that Marler mentions:

“‘Incomplete’ song is an abbreviated form in which the end-phrase and terminal parts of the trill are omitted. It is more or less confined to a short period in the spring. ‘Plastic’ song is characteristic of males early in their first spring. It is highly variable but following the same basic pattern. ‘Congested’ song is least like normal song in form. Given when the male is strongly stimulated sexually, it consists of songs repeated rapidly and softly with no interval between and with end-phrases often repeated two or three times, and portions of the trill sometimes omitted. Whole songs are often compressed into half their normal duration. It is usually associated with frequent subsong [...]” (86)

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Duetting, or as Marler calls it ‘countersinging’, is more common in other species, but also occurs in chaffinches to some degree. In such a case the replying bird tends to sing a song that resembles the first bird’s song the closest, but often they get gradually out of sync, because they sing in a slightly different rhythm (84-85). Marler (1961) points out that there are different types of information within one utterance, in this case the chaffinch’s song. Firstly, it contains species-specific information, since it is produced and understood by chaffinches. There are some signals that lack species-specific information, such as the specific alarm call consisting of a high squeak, which is used to indicate a hawk flying overhead, for example. This alarm call has been used by other, smaller woodland birds in order to be exposed to a minimum of danger, but chaffinches also react to these ‘false’ alarm calls, which proves that they do not contain any species-specific information. Secondly, it contains sexual information, since signals emitted by males try to evoke a pair bonding with a female in the appropriate physical condition. Thirdly, there is individual information apparent in the song, since every male has some particular characteristics that make his song unique and link it to him as an individual. Fourthly, the male’s foremost motivation is to communicate to other individuals that he is in a reproductive state, which is an example of motivational information. And lastly, the chaffinch’s song also contains environmental information on the fact that he is either within his territory or intruding in another male’s territory, or even information on the presence of food or which season it is (1961: 259-267). This all tells us that the influence of context, again, is very high, and that the content of the message is highly context-specific.

In his chapter on flexibility in bird song, which mostly deals with song diversity and accuracy and versatility of learning, Lachlan (2008) also mentions the chaffinch multiple times. With regard to song diversity, Lachlan prefers a ‘microgeographic’ approach, which focuses on the “variation between neighboring individuals rather than between neighboring populations” (2008: 308). This pattern of variation is affected by a number of parameters, namely: rate of cultural mutation, dispersal, repertoire size, song preferences, and demography (309). Chaffinches do not show the tendency to share song types with neighbours more than males that are slightly further away, and even statistical analyses show that chaffinches avoid learning from neighbours (309-310). The author states that the “simplest hypothesis is that many chaffinches learn their songs before they disperse from their father’s territory” (310).

Lachlan also touches upon the question of why birds like chaffinches learn their songs with such an accurate precision, since it is quite a time-consuming process. He discusses two general hypotheses, which I will here summarise very concisely. The first hypothesis is that birds benefit from learning a song accurately, but that it does not matter which song in the population specifically they pick. The simple explanation for this is that accuracy improves the chances of developing a species-typical song that is easily recognized by conspecifics. The second

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hypothesis, on the other hand, is that research and experimentation show that “there is some communicative function served by singing one particular song type compared to another” (311-312). This leads the author then to elaborate on the notion of what he calls “conformity-enforcing behavior” (313), but I will not go into that much detail here.

With regard to the concept of ‘versatility’, Lachlan remarks that bird song in general displays a large variability across several dimensions, both within a species and between different species (315). Concerning chaffinches in particular the author mentions the following:

“Chaffinches, among other species, seem to be able to produce an incredibly large number of different songs. Even though chaffinch song is one of the easiest songs to recognize and apparently obeys very strict organizational rules, there seem to be hundreds of different types of elements within a population, arranged into an effectively infinite variety of song types (note that despite this potential, each individual chaffinch male only sings a repertoire of typically two or three song types, with typically fewer than fifty elements).” (316)

Variation in vocal signals might be linked to the development of the organs involved in vocal production, which often differs among species, or the individuality of the calls might have communicative relevance in several species (320). There is also the hypothesis of a ‘hybrid zone’, where “a larger degree of variation between individuals might arise temporarily in certain situations” (321).

If songs are so variable, how does this variation not lead to the potential confusion between species? And how did the versatility of songs evolve? Some studies have found that females prefer larger repertoire sizes (which indirectly reflects a deeper sensory bias for variability). No experimental evidence has been found, however, “for female preferences for songs unlike those found in their locale, while there are several studies demonstrating female preferences for local song types” (316-317).

With regard to the evolutionary processes behind birdsong Lachlan points out that vocal learning only evolved three times in a period of 100 million years, and once it evolved, it tended to be maintained (320). It is also intriguing to consider that “versatility may have evolved simply as a by-product of the interaction of genes and culture and not because of communicative functions with which versatility may be associated” (ibid.). The author concludes that songbirds, in all their diversity, are a real “cornucopia of different types and levels of signal structure, organization, versatility, and complexity” (322).

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3.2.1.3. Zebra Finches The vocal repertoire of songbirds consists mostly of songs and calls that are supposed to initiate pair bonding through duetting. When a pair is established the vocalizations are not only used to “signal commitment and reinforce the pair bond”, but also for “nest building, territory defense, reproduction, chick-rearing and the formation of a long-term partnership” (Elie and Theunissen 2016: 285). Furthermore, it is also used for communication of distress, predator avoidance, establishment of social ranks, mate guarding, and territorial defense (ibid.). Elie and Theunissen (2016) also researched the vocal repertoire of the domestic zebra finch, and I will shortly summarize their findings. The first type of calls is found only in baby birds, and is called juvenile calls. Only a few days after birth chicks start to emit ‘begging calls’, which sound like “soft cheeping sounds”, and are often performed while “displaying the typical head twisted open beak posture of zebra finches” (2016: 297). Another type of juvenile calls is the ‘long tonal call’, which is a “contact call produced by chicks who are about to fledge”, especially “when they lose visual contact with members of their family” (299). There are a number of affiliative calls. The first one is a ‘contact call’, which is split up in what the authors call ‘tet call’, which is a shorter and softer call for short-range communication, and a ‘distance call’, which is louder and longer and used for long-range communication. The ‘distance call’ is only produced when the zebra finches are out of immediate visual contact with the colony, their mate or the fledglings they care for (300-301). ‘Nest calls’ and ‘whine calls’ are produced by paired birds in the environment of the nest only, for example “when they are searching for a new nest, when they are building their nest and almost each time they relieve each other at the nest during the brooding period” (301). There are also non-affiliative calls, such as the ‘wsst call’, which is an “aggressive call often produced right before an attack” (302). ‘Distress calls’, on the other hand, are emitted “when they are attacked by other conspecifics, usually while they are escaping or being brutalized by their aggressor” (ibid.). These types of calls have been observed to be the noisiest type of vocalizations. Finally, there are two types of alarm calls: the ‘thuk call’, which is produced by parents only and directed at their chicks specifically, and the ‘tuck call’, which is a more generic alarm call. These types of calls have been observed to be the shortest type of vocalization (ibid.). Aside from calls, zebra finches also produce song. These more complex vocalizations, which are “composed of introductory notes followed by multiple motifs each made of a stereotyped sequence of song elements or syllables”, are mostly emitted during “courtship, pair bonding and mating behavior” (303). Elie and Theunissen summarize as follows:

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“[...] the zebra finch has a complex vocal repertoire of call types and song elements that are used in very specific behavioral contexts. On the one hand, all the vocalizations were broadband and showed a relatively restricted range of fundamental frequencies (at least relative to the human pitch scale) and, because of this, exhibited a characteristic zebra finch sound quality. On the other hand, the vocalization types were clearly distinct from each other both to trained ears and in our quantitative analyses.” (304)

A completely different aspect of zebra finch vocalizations that emerges from the research is that of ‘pauses’ and how it enhances grouping of song elements. In their study of pause, co-occurrence and song memorizations, Spierings et al. (2015) found that “pauses between chunks of song elements might function not only as an aid to song learning in juvenile birds, but also to song discrimination in adult birds of both sexes” (2015: 873). In another study, Spierings et al. (2017) tested the iambic-trochaic law, which is the typically human tendency to group successive tones in iambs and trochees (respectively, a stress pattern of ‘short-long’ and ‘long-short’), in zebra finches. Their results suggest that this tendency is not only limited to humans, but that the “perceptual bias to group pitch variations into trochees” might be a “universal perceptual primitive” (2017: 673). Finally, I want to point out, again, that many of the experiments conducted show a very high rate of human intervention. Another example of such a study is one by Chen et al. (2016), researching the concepts of morphology and sequential memorization, and more specifically the concept of ‘affixation’, through experimentation. These types of studies show how typically language-like features also occur in animal communication, but that does not necessarily mean that zebra finches use these affixation-like patterns in the wild. Another example of such a study is by Van Heijningen et al. (2013), researching the rule learning strategies of zebra finches through an artificial grammar learning task. Because we are dealing with an artificial grammar and because of the fact that the rate of human intervention is so high, I think that such studies do not add much value to the research of the natural behaviour and communication system of zebra finches.

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3.2.2. SFG Approach In this section I will focus mainly on the communication system of the songbirds discussed in the previous section, and look at how their vocalizations, which are acquired through vocal learning, can fit into a stratification model and how it relates to the metafunctions.

Generally, the first thing one notices in the literature on birdsong is the importance of context. At first glance, the context in which these birds live and communicate is either ‘natural’ (in their natural environment), ‘domestic’ (in captivity; e.g. as a pet), or ‘experimental’ (in captivity, but used for scientific research). Besides this threefold division of situational contexts, there are, however, many more contextual circumstances, such as environmental, hormonal, and social contexts. Examples of such circumstances are the involvement of humans, the possible presence of aggressors, the seasonal hormonal fluctuations in males that lead them to pair bonding behaviour, etc. Consequently, vocalizations and their corresponding meanings are highly context-dependent, which is also reflected in the structure of the stratification model. The outer circle, which represents the ‘Context’, encapsulates the two other circles that represent respectively the ‘Level of Content’ (the meaning) and the ‘Level of Expression’ (the means of expression). See Figure 7 for a visual representation of the stratification model applied to the general communicative system of songbirds.

Figure 7: Stratification applied to the general communicative system of songbirds

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Although this general overview might be helpful to understand the basic workings of the communicative system of the songbirds in general, it is, in my opinion, more interesting to look at the specific species discussed earlier in more detail and one by one.

Male starlings only have two types of vocalizations: warbles and whistles. Each type of vocalization has a particular function within a specific context. Instead of visualizing the stratification concept by means of co-tangential circles, this time I chose a schematic representation because it is more orderly. See Figure 8 for a schematic representation of the starling’s vocalizations. Context Meaning Vocalizations

- Male individual

- Pairing or foraging

situation?

- Number of other birds

present? Females or

males?

- …

- Attracting females Warbles

- Seeking to engage in a

duet with females

- Male-spacing

Whistles

Figure 8: Schematic representation of the relationship between ‘meaning’ and ‘vocalizations’ in starlings Here we see that the relationship between warbles and whistles is not very clear-cut. The meaning is context-dependent: are the vocalizations uttered in a pairing or a foraging situation? Are there any other birds in the proximity of the performer, and if so, how many and what is their sex? If there are any males in the vicinity, a male individual might use a specific type of whistle to repel the other males, while if there was only a female around, another type of whistle might be used to catch the attention of a female willing to engage in a duet. With regard to chaffinches, the scheme looks relatively similar, except for the fact that the ‘warbles’ and ‘whistles’ are to be replaced with ‘song’, ‘incomplete song’ and a specific ‘alarm call’. Songs often have the function of attracting females and repelling males, but in the case of the chaffinch there are multiple layers of extra meaning that give information on the environment, and the sexual intentions of the individual. An example of a situation where an alarm call is appropriate is when an individual spots a suspicious movement above him (since this could be a hunting hawk). See Figure 9 for a schematic representation of the chaffinch’s vocalizations.

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Context Meaning Vocalizations

- Male individual

- Pair bonding situation?

- Inside or outside the

territory?

- Human intervention?

- …

- Attracting females

- Repelling other males

- Additional layers of

species-specific

environmental, sexual,

individual and

motivational information

Song

- Chicks learning other

vocalizations

Incomplete song

- Signalling danger Alarm call (high squeak)

Figure 9: Schematic representation of the relationship between ‘meaning’ and ‘vocalizations’ in chaffinches With regard to zebra finches, the scheme is even more complex, since the vocal repertoire of chaffinches is so large. Again, ‘song’ is one of the types of vocalizations that is commonly used to seek contact with a female that is willing to engage in pair bonding. In addition to ‘song’, however, zebra finches also display a whole range of ‘calls’, ranging from specific calls emitted by chicks to non-aggressive contact calls and specific alarm calls. See Figure 10 for a schematic representation of the zebra finch’s vocalizations.

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Context Meaning Vocalizations

- Natural or domestic/

experimental

environment?

- Before or after pair

bonding situation?

- Human intervention?

- …

Chicks seeking attention in the

environment of the nest

Juvenile calls

- ‘Begging calls’

- ‘Long tonal calls’

Seeking contact in a non-

aggressive manner

Affiliative calls

- ‘Tet calls’

- ‘Distance calls’

- ‘Nest & whine calls’

Expressing distress or fear

caused by an aggressor

Non-affiliative calls

- ‘Wsst calls’

- ‘Distress calls’

- ‘Alarm calls’ (thuk/tuck)

Seeking contact in pair

bonding and mating situations

Song

Figure 10: Schematic representation of the relationship between ‘meaning’ and ‘vocalizations’ in zebra finches When looking at the metafunctions in bird song and in the process of vocal learning, we can notice that there is a structure of interconnected meanings that underlies the vocalizations. With regard to the ideational metafunction, which consists of an experiential aspect and a logical aspect, songbirds do have the cognitive abilities that allow for a communicative system, which is more complex than imitative behaviour or simple instinctive calls. They are able to express and organise concrete thoughts (but also more abstract ideas related to interspecific relationships, predator behaviour, and general spacing within a territory) through vocalizations, and the fact that the relationship between an utterance (whether that is a song, a call or a whistle) and that the meaning is not always a one-to-one relationship can be explained on the basis of the context specificity.

These vocalizations are not only highly species-specific, but also singer-specific. This leads us to the interpersonal (or ‘interindividual’) metafunction, since songbirds often use peculiar characteristics in motifs to make the identification of individuals easier. The interaction between individuals, for example in duets (or ‘countersinging’), does not only tell us something about the communicative behaviour of songbirds, but also about some completely different

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aspects of songbird vocalizations, such as regional (or ‘dialectal’) variation, accuracy, and versatility. We have seen that there is a high rate of versatility both within and among species, and the fact that birds do not often confuse between vocalizations of different species, and even interact with different species, shows that the interpersonal metafunction is well developed.

Finally, when we apply the textual metafunction to bird song, the first thing one notices is that this type of communication uses only one modality, and that is the auditory modality. Vocalizations cannot be written down, with the exception of a spectrogram, which is a visual representation of a spectrum of sound frequencies. In the case of the zebra finch, several researchers used these spectrograms to study the vocal repertoire and the use of pauses, for example in the papers by Elie and Theunissen (2016) and Chen et al. (2016). To conclude this section, it is important to emphasize that many of the vocalizations found in songbirds are more complex than they seem at first sight, and that they display language-like features (such as recursion, affixation, sequential ordering) and, above all, a relationship between the levels of content and expression that is highly context-dependent.

3.3. PRIMATE VOCALIZATIONS AND GESTURES 3.3.1. General Introduction From an evolutionary viewpoint, primates are the closest species that share a common ancestor with humans. For this reason many scholars have pointed out that studying the communication systems of primates might be our best chance to gain insight in how human language emerged and developed over time; or as Byrne et al. (2017) phrase it: “the communication of the great apes [...] holds out the promise of understanding the evolutionary origin of human language [...], often cited as our greatest cognitive distinction from other animal species” (2017: 755). The authors refer to ‘great apes’, because the entire species of primates can be split up in several groups. A common distinction is that of ‘monkeys’, such as vervet monkeys, Diana monkeys, squirrel monkeys, macaques, marmosets, etc. on the one hand, and ‘apes’, such as chimpanzees, bonobos, orangutans, gorillas, etc. on the other hand. This distinction is partly based on what the main modality of their communication system is. In general, monkey communication relies on vocalizations (such as alarm calls), while great apes use more gestural communication. There is also a difference in cognitive abilities, for example in the fact that some great apes use tools, especially chimpanzees (Plotnik and Clayton 2015: 34). Above all, gestural communication is intentional and flexible, while vocalizations have a more fixed meaning and are used more instinctively.

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There is, however, also a great deal of commonalities between monkey and ape communication. Plotnik and Clayton (2015) point out that all primates “overwhelmingly solve problems in their environment by processing visual information, although primate vocal communication certainly affects social decision making” (2015: 43). Leavens et al. (2010) point out that in all primates “facial expressions, body postures, and vocalizations all have important functional roles in both intraspecific and interspecies communication” (2010: 34). Interestingly, research on the basis of computer models shows that the role of cognitive patterns in the social behaviour of primates is overestimated, and that simple reactions (i.e. micro-rules) generally lead to complex social behaviour (i.e. macro-patterns) (Hemelrijk 2012: 223).

Carpenter (1969) discusses the characteristics and functions of naturalistic communicative behaviour in primates, which I will summarise here in short. The author points out that the communicative system of primates consists of many components and elements, and that the context, events, processes and interactions all include patterns that carry information (1969: 59-60). A first example of such a component of information is the classification into the geophysical (i.e. landforms, climate, etc.), the biotic (i.e. the fauna and flora), and the social (i.e. the number of individuals and interactions) (60). A signalling act leads to a ‘stimulus pattern’, which can consist of odour, contact stimulation, visible movements, or audible sounds, or a combination thereof. The characteristics of the stimulus pattern must be “of such quality and strength as to be sensed and perceived by the responding animal or animals”, and more importantly, must be “attended to and perceived in order to become communicative in function” (ibid.). Consequently, there is not only “retroactive cycling or ‘feed-back’ stimulation” apparent in the course of their communicative events, but it is also true that the interactions are reciprocal (61). These communicative processes do not only convey information about the environment, they also function as ‘regulators of behaviour’. A specific communicative act can stimulate or arouse a specific kind of behaviour, such as ‘defence’, ‘caution’ or ‘play’. Another important aspect that plays a large role in the regulation of behaviour is that of the status of the signaller and the receiver, and how the ‘signal value’ determines the strength of the communicative act (Carpenter 1969: 61-62). Another component of the primate communicative system is the ‘field of signalling’, which is concerned with the variations in numbers of patterns and individuals participating in the communicative act. Carpenter (1969) gives an overview of the range of patterns: “(1) one-to-one, (2) one-to-many, (3) many-to-one, and (4) many-to-many” (1969: 62). Added to that, there is also an ‘effective distance continuum’, which is described as the distinction between ‘intra-group interactions’ on the one hand, and interactions with the function of “probing and exploring beyond the range of vision” (64) on the other hand. A final characteristic of primate signalling behaviour is that of ‘stereotypicality’ of vocal and gestural patterns. By this is meant that “signal

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information is species or, more accurately, genera specific”, and that the calls of some primates become ‘ritualized’. The author defines this ‘ritualized behaviour’ as having “sociobiotic utility and functionality” (65-66). With regard to the functions of signalling systems, Carpenter (1969) describes the first function as “excitatory, inhibitory, and guiding”, which includes: initiating group movements, regulating spacing of individuals, and other signals related to territory. Another function is that of ‘individual identification’ (sex, social status, age class). A particular set of functions can be found in ‘female and her infant behaviour’, but also in the playing activities between young juvenile primates (1969: 66-67). The author concludes that signalling “serves as an instrumental act and substitutes for corresponding raw, and energy consuming behavior” (68), and points out the influence of stress:

“A final function of signaling behavior in primates should be indicated: signaling behavior is most prominently displayed during periods and conditions of stress, for instance when two or more groups meet, or when there is conflict within the group. Signaling is prominent in crises and when ‘enemies’ or animals perceived as ‘enemies’, including man, disturb groups.” (ibid.)

Contextual flexibility also plays a major role in primate communication. Snowdon (2008) states that contextual flexibility occurs when (1) “there appear to be multiple mappings between the situations in which a signal is produced and the responses of recipients”, and (2) “when the usage and understanding of a traditional signal is applied in novel circumstances” (2008: 77). The author then discusses flexibility during the development of primates, since developmental processes “affect the structure, usage, and comprehension of signals”, but he also elaborates on the use of flexibility in adult usage and on the influence of social status. He eventually concludes that:

“There is extensive evidence of contextual flexibility among nonhuman primates within adult communication and in changes in context signal relationships during development. Furthermore, at least in some species social status serves as an important context that affects signal production. From the perspective of nonhuman primates, the notions of fixed-action patterns and signed stimuli may still be present in a more sophisticated form in the predator-specific alarm calls of some species, but contextual flexibility in communication may be more the rule than the exception.” (87-88)

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It is also interesting to note that there is a heated debate on the notion of ‘meaning’ in primate communication. Scott-Philips (2016), on the one hand, argues that ‘meaning’ in the Gricean sense (as mentioned before) does not apply to great ape communication, since they have a different degree of overt intentionality. Moore (2016), on the other hand, argues, based on evidence of ostensive communication, that there are “no strong grounds to deny that chimpanzee gestures have meanings” (2016: 229). Scott-Philips rebukes the arguments proposed by Moore, and concludes that “the best provisional view for non-human primate communication is that it is most likely not meaningful in the same way that human words are” (Scott-Philips 2016: 237).

Some researchers have pointed out that there is too much of a distinction being made between vocal and gestural communication in primates, and that the focus should be on the multimodality of communication, i.e. the interplay between different modalities. Fröhlich (2017), for example, emphasizes the importance of multimodality and critiques the lack of a holistic approach. She points out that apes do not vocalize or gesture in isolation, and that it has been demonstrated that primate communication is inherently multimodal at both the behavioural and neuronal level, referring to studies in both macaques and chimpanzees (2017: 202). Yet, when discussing ‘turn-taking’ in primate vocal communication she refers to “lemurs, marmosets, titi monkeys, squirrel monkeys and siamangs” (which are all monkeys except for ‘siamangs’), and when she discusses primate gestural communication she points out herself that “in great apes, gesture seems to be a prevalent mode of communication, with extensive gestural repertoires produced across a wide range of social contexts” (204).

Although it is true that monkeys and apes are quite the same in some aspects, with regard to their communicative abilities, they clearly differ mostly in the modality of their communication system, viz. the focus lies either on the auditory or on the visual modality. Thus, I will discuss the two modalities separately: first the use of vocal communication in some monkeys, followed by a discussion of gestural communication in great apes.

3.3.1.1. Vocal Communication As mentioned before, vocalizations such as territory calls or alarm calls are used by a whole variety of monkey species. In this section, though, I will only discuss two different monkeys: vervet monkeys (Chlorocebus pygerythrus) and Diana monkeys (Cercopithecus diana), because they belong to the same family of catarrhines, namely the Cercopithecidae, or ‘Old World monkeys’. With regard to this family of monkey species, Griffin and Speck (2004) point out that according to new evidence vervet monkeys, Diana monkeys, Campbell monkeys and African green monkeys (all belonging to the Cercopithecidae family) use different alarm calls for

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different predators, and even react to each other’s calls. Callitrichidae, or ‘New World monkeys’, such as tamarins and marmosets, who are further away from great apes and humans in phylogenetic terms, do not only show remarkable cognitive and communicative abilities, they also display complex call structures, diversity in babbling, and regional dialects (Snowdon 2001: 247). Nevertheless, because of the scope of this paper, I will limit this section to the discussion of vervet monkeys and Diana monkeys only.

Vervet monkeys are mostly known for their alarm calls. Lestel (2002), who summarised some of the human language-like features in animal communication, mentions vervets monkeys multiple times. For example: the alarm calls and the following responses show traditional and dialectal features, which means that they have “local, acquired characteristics of the modes of communication which are passed on from one generation to the next” (2002: 382). Another example of such a language-like feature is meta-communication. Adult vervet monkeys correct juvenile monkeys if they express themselves wrongly or in an inappropriate context (ibid.). Wheeler et al. (2012) point out that there is evidence of ‘functional reference’ found in the calls of vervet monkeys (2012: 199), and that “infant vervet monkeys show semantic-like, predator-specific alarm call production well before any understanding of the significance of those calls is evident on the receiver side” (194). Fischer (2012), however, points out that acoustic signals can vary both in call type and in sender identity. She states:

“[...] listeners process who is calling, and they may vary their responses in relation to signaler reliability. The amount of information extracted in terms of identifying the caller remains the same. At the same time, the same signal may elicit quite distinct responses, depending on the context in which it occurs. Although it has not been demonstrated experimentally, it is conceivable that receivers are able to classify a call as belonging to a certain category (“alarm call”) while varying their response in relation to context (“no predator in sight” vs. “a lion right in front of me”).” (2012: 158)

Snowdon (2008) mentions a specific case where it was reported that one type of alarm call was not used for one specific predator, but for a range of predators, depending on the context. He describes that one alarm call was given to “martial eagles, crowned hawk-eagles, as well as to lions, leopards, and other cats”, while the call “given to snakes was also very similar to a call given toward an observer and toward other vervet groups” (2008: 75). This indicates not only that there is not a real one-to-one correspondence between the utterance and the meaning, but it also suggests that the importance of other contextual factors is much larger than expected (ibid.).

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Snowdon (2008) also mentions Diana monkeys, and points out that they have specific calls for leopards and eagles, since these predators have very different hunting strategies. The author uses the leopards as an example. When Diana monkeys spot a leopard, they will perform their specific ‘leopard call’, and since leopards depend on the act of surprising their prey, the predator will be forced to move on and find another prey. This is contrasted with how Diana monkeys react to the presence of chimpanzees, whose natural behaviour is to approach and even hunt down Diana monkeys. When a Diana monkey hears a group of chimpanzees approaching, their initial reaction is not to perform a specific alarm call, but rather to freeze and remain silent, which leads us to the conclusion that Diana monkeys are able to differentiate between predators and “use different strategies with each predator” (2008: 74).

Another study, conducted on female Diana monkeys by Candiotti et al. (2012), shows that there are four vocal structures (or combinations thereof) available in the repertoire, and that they are all heavily context-related calls. The four different call types are identified as ‘H’ (high-pitched trilled calls), ‘R’ (repeated-unit calls), ‘L’ (continuous low-pitched quavered structures), and ‘A’ (calls characterised by a tonal arched-shape frequency modulation of 3,047 ± 774 Hz) (2012: 332). With regard to the functions of the calls, ‘H’ calls were associated with “high mobility, high spatial cohesion, being outside of the territory, high luminosity and the presence of neighbours”, but also with “socio-positive or relaxed situations and were often uttered in isolation”. ‘L’ calls were associated with “high mobility, low spatial cohesion, being in the center of the territory, high luminosity and vocal chorusing”. ‘R’ calls were significantly associated with “being in the center of the territory, high spatial cohesion, low luminosity and socio-negative situations”, and uttered “mainly in isolation of other vocal behaviour”. Finally, ‘A’ calls were associated with “group resting, being in the core area of the territory, low spatial cohesion, low luminosity, neutral situations and vocal exchanges” (2012: 333).

Interestingly, call combinations were “optional and always in the form of a two-compound utterance” (2012: 337). Moreover, the second element of the combination was most often the contextually neutral ‘A’ call, which seems to function as a contextual refiner. Candiotti et al. (2012) explain: “call combination seemed to modulate the utterance of an ‘A’ call with a contextual value regarding the immediate situation faced by the emitter in terms of ‘positive or relaxed’, ‘negative or potentially dangerous’ or ‘neutral’ situation” (ibid.).

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3.3.1.2. Gestural Communication In this section I will discuss the gestural communication of the family of the great apes (Hominidae), but the main focus will be on two subspecies of the genus Pan: namely the chimpanzee (Pan troglodytes) and the bonobo (Pan paniscus).

There is some debate on whether gestural signals are intentional or behavioural. Some scholars, such as Byrne et al. (2017), Call (2008) and Cartmill and Byrne (2010) state that the gestures that apes make are indeed intentional. Byrne et al. (2017) points out that there is evidence that “a signaller has a specific result in mind, in terms of another individual’s behaviour, and will work flexibly to achieve that result”, while there is no evidence that “ape signallers intend to change the knowledge or beliefs of their audiences” (2017: 757). Call (2008) adds to that, with regard to chimpanzees in particular: “chimpanzees adjust their gestures to the attentional state of the recipient” and “not only do they use gestures whose sensory modality is appropriate to the state of the recipient but they also can alter the recipient’s attentional state by placing themselves in front of her” (2008: 242-243). Cartmill and Byrne (2010) conclude that, although “a movement that one individual uses as an intentionally communicative gesture may be used by another individual in a non-communicative way”, “evidence for intentional use of gestures has been found in several ape species” (2010: 794). Other scholars, on the other hand, such as Plotnik and Clayton (2015), suggest that changes in the behaviour of apes (although in this case only chimpanzees are mentioned) are due to the “ability to read partner behavior rather than an understanding of partner mental states” (2015: 37).

Besides the discussion of whether the use of gestural signals is instinctive behaviour or socially learned, another discussion arises concerned with the degree of iconicity: are the signals iconic, deictic, or even symbolic? Cartmill and Byrne (2010) state that studies focused on a single gesture type or on a single gesture in an individual have found both deictic gestures (in captive and wild chimpanzees) and iconic gestures (in a captive lowland gorilla) (2010: 795). Lestel (2002) mentions some examples of newly discovered forms of communication, such as chimpanzees drumming on trees and bonobos leaving signs on their path to find their way back, as examples of having the potential for symbolic communication (2002: 384). Also, some chimpanzees can communicate with humans through conventional symbols, which brings us back to the idea of ‘humans as universal interlocutors’. However, only one individual, a bonobo named Kanzi, has been found to have the real capability of communicating via an advanced symbolic system of ‘lexigrams’. At the end of this section, when discussing the gestural repertoire of bonobos, I will return to Kanzi and discuss this fascinating individual in more detail. Since true

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symbolic communication has only been found in a few individuals, Wheeler et al. (2012) conclude that the “use of iconic gestures by great apes remains controversial” (2012: 200).

With regard to imitation, Zentall (2006) mentions that gestural imitation, which he defines as “a form of imitative learning [where] the gestures of a model are copied”, occurs in chimpanzees and orangutans (2006: 344). Sequence imitations also occur, and in contact with humans, some apes can respond correctly to commands such as ‘do this!’ or ‘do-as-I-do!’, which is a form of generalized imitation (345-346).

As I have mentioned before, Byrne et al. (2017) state that the intentional usage of gestures has been found in bonobos, gorillas and orangutans, as well as chimpanzees (2017: 756). It is important to note that these gestures vary in modality, meaning that: “some involve contact with the recipient’s body, so [they] can be detected by tactile sensation even in an inattentive audience”, while “others do not, but [they] produce an audible sound which may attract the attention of the audience to notice the gesture, or may be interpretable even without looking” (ibid.). The repertoire of gestures is relatively large and extensively shared among the species Pan troglodytes, Pan paniscus, Gorilla, and Pongo. For a catalogue of the shared repertoire of these great apes (with desciptions and futher information), I refer to Byrne et al. (2017: 758-761). The authors acknowledge that the discussion of ‘meaning’ is a heated topic, yet they agree upon the claim that the meaning that is associated with a gesture is highly context-dependent, for example in play, or among individuals from a different social, age or sex class. Experiments show that some gestures convey the same meaning, and are consequently redundant, while at the same time other reactions (what the authors call ‘ASO’: “apparently satisfactory outcome”) were associated with a single gesture (764-765). They conclude by saying that there is no evidence for syntax, since the sequential order of the gestures does not change the meaning, and that, although great apes can learn new gestures, the only thing that prevents them from learning new gestures is the lack of imagination (766-767).

A key component in the evolution of communicative systems is ‘flexibility’, because it allows individuals to adapt and overcome communicative issues in problem-solving situations. Call (2008) deals with the notion of ‘flexibility’ of ape gesturing and remarks that many authors have argued that in the problem-solving situations “the use of gestures is analogous to the use of tools” (2008: 235). He also touches upon very similar concepts that I have mentioned previously. The author claims that “multiple gestures can be used for a particular context”, which he calls a “dissociation between means and ends”, and emphasizes the influence of context in a specific situation or activity, such as “play, sex, grooming, body contact, food transfer, or change of posture or location” (237). Interestingly, 20-30% of the gestures are combinations or sequences of two or more gestures. Most often, the sequences are just repetitions of a single gesture in rapid succession, but if the gestures differ, the two-gesture combinations are by far the most frequent

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ones (around 70% of the multi-gestural sequences that were observed). Call (2008) summarizes this as follows:

“[The] data suggest that there is not a one-to-one correspondence between gestures and contexts of use. Multiple gestures are used in one context, while at the same time one gesture is used in multiple contexts. Some gestures are also used for multiple functions. One could say that many of the ape gestures constitute a ‘toolbox’ that can be used flexibly to achieve particular goals.” (238)

Call (2008) also gives an insight in gestures that do not belong to the natural repertoire. He describes these gestures as ‘novel gestures’. The distinction that can be made within this category is twofold: on the one hand, there is ‘pointing’, and on the other hand, there is ‘sign language’. It seems odd to humans, who frequently use an extended index finger to point at something, that this gesture is not natural to the repertoire of great apes. Interestingly, chimpanzees use their body orientation to point towards something. Thus, pointing behaviour (either with a finger, hand, or arm) in apes only arises in contact with humans (2008: 244). The same goes for sign languages. Great apes can be taught to understand and produce some aspects of human sign languages. Most studies that were concerned with teaching a sign language to a great ape used ASL (American Sign Language), and, surprisingly, “the size of the sign repertoire that has been achieved with apes varies between 100 and 200 signs” (247). It is quite remarkable that, although some of these signs are iconic, many of them are truly symbolic. Unfortunately, it is unclear to what degree apes use these signs in the same way as humans do. Although they do use combinations of signs, “there is little evidence that these combinations follow syntactic rules” (ibid.).

Before I go deeper into the gestural repertoires of chimpanzees and bonobos, I want to mention one study, conducted by Cartmill and Byrne (2010) that was concerned with the gestures of orangutans, or more specifically, two species of captive orangutans: Bornean orangutans (Pongo pygmaeus) and Sumatran orangutans (Pongo abelii). The researchers found six different examples of intentional meanings, related to six social goals: “to initiate an affiliative interaction (contact, grooming, or play), request objects, share objects, instigate co- locomotion, cause the partner to move back, or stop an action” (2010: 793). They conclude that the gestures are made with the expectation of specific behavioural responses, and consequently, that they have intentional meanings as well as functional consequences (802-803).

It is no secret that chimpanzees are highly intelligent animals and that their cognitive abilities resemble those of humans in some aspects. Griffin and Speck (2004) point out that there is new evidence for some advanced forms of tool use. For example, chimpanzees in captivity have been observed to fold leaves for holding drinking water. Another study even shows the use

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of tokens, which the chimpanzees not only used as an exchange for desired food, but also saved the tokens for future use (2004: 12).

With regard to chimpanzee gestures, similar discoveries of remarkable cognitive abilities have been made. Byrne et al. (2017) point out that a chimpanzee would “typically wait briefly after gesturing (“response waiting”), continuing to monitor their audience to assess the behavioural outcome; if no result was forthcoming, they would persist in gesturing, and if their audience had apparently not seen them, they would move round in front of them before persisting in gesturing” (2017: 756). Interestingly, concerning conversational and turn-taking behaviour, Fröhlich (2017) points out in one of her case studies that, generally, chimpanzees engage in “prolonged communicative negotiations” (2017: 204). From a multimodal perspective, Leavens et al. (2010) remark that captive chimpanzees in interaction with humans change the modality of their signals based on the context. Experiments with chimpanzees concerned with the change in context-based modalities show that they display “a range of different visual signals when a human experimenter was facing them and a range of different auditory or tactile (attention-getting) signals when the human was facing away from them” (2010: 33).

As I have already pointed out in this section, gestures are flexible across contexts, which means that a single gesture can be used in multiple contexts and vice versa. The gestural repertoire of the chimpanzee is well documented, both in the wild and in captivity. Research shows that flexibility in communicative persistence is apparent in both wild and captive chimpanzees (Roberts et al. 2014: 318). Hobaiter and Byrne (2011) mention 66 distinct gestures in wild chimpanzees, with only small differences between individuals (mostly because of the age class). Roberts et al. (2014) take a slightly different approach and split the total amount of gestures they found in the repertoire of the wild chimpanzee into 65 manual gestures and 55 bodily gestures. The authors also point out that gestural communication may have played a role in the emergence of increased flexibility in social bonding (2014: 317). Since it is not very useful to give the entire repertoire of chimpanzees here, I would like to refer to Hobaiter and Byrne (2011: 753-759) and Roberts et al. (2014: 320-325) for a more complete overview of the entire gestural repertoire.

It might not seem remarkable that the gestural repertoire of chimpanzees overlaps with that of other great apes, but the numbers are quite impressive: 60% overlap with the repertoire of gorillas, 80% with that of pongos (Hobaiter and Byrne 2011: 765), and 88% with that of bonobos (Graham et al. 2017: 173-174). With regard to this remarkable overlap between genera, Hobaiter and Byrne (2011) state: “instead of merely a species-typical repertoire, it seems that the great apes share an extensive family-typical repertoire of gestures: indeed, the same 24 gesture types were found in all of Pan, Gorilla and Pongo” (2011: 765).

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Graham et al. (2017) discuss the gestural repertoire of the wild bonobo. They make a distinction between the expressed repertoire, i.e. “the set of gesture types that an individual deploys” and the understood repertoire, i.e. “the set of gesture types that an individual receives and subsequently understands” (2017: 172). The authors conclude that bonobo gestural communication is “an intentional, flexible, mutually understood communicative system” (176). Interestingly, with regard to the remarkable overlap of 88% with the chimpanzee gestural repertoire, they state:

“The bonobo and chimpanzee repertoire therefore seem, to a very considerable extent, to be Pan-typical. However, the question remains: Do bonobo and chimpanzee gestures mean the same thing? Despite the differences in social behaviour between bonobos and chimpanzees, differences in the gestural repertoire are minor and perhaps artefactual: but while the gesture form might be biologically fixed, the meaning may not be and remains a potential source of inter-species differences.” (177)

Graham et al. (2017) do acknowledge the biological basis in both species of Pan, but they also raise questions of whether the meaning of the gestures in the shared repertoire is truly the same, and whether further comparative studies between the two species are needed. Returning to the multimodal approach, Fröhlich (2017) mentions the ‘multiple message’ hypothesis, which, in short, states that “different information is conveyed in each channel, resulting in increased information content” (2017: 203). Indeed, a recent study shows that male bonobos use the same vocalization for play and aggression, but “add gestures to distinguish between the two contexts” (ibid). This study supports the ‘multiple message’ hypothesis, since “a message sent in one channel is disambiguated by adding a more specific component in another channel” (ibid.).

Finally, I want to discuss a specific individual: the bonobo Kanzi. Rather than using vocalizations or natural gestures, this individual was able to learn to use a lexigram keyboard in order to communicate with humans without being explicitly taught or trained. I include this in my overview, since the lexigram keyboard is operated through pointing, which is in fact an acquired form of gesturing. Interestingly, it was initially Kanzi’s mother who was trained to communicate through a lexigram keyboard, but she showed only little interest. Kanzi, however, who was an infant at the time of the experiment, easily picked up the use of the lexigrams (Benson and Thibault 2009: 105). Lestel (2002) explains that Kanzi is a special case indeed, since experiments have shown that his natural calls differ from those of other bonobos in that he vocalizes more and uses new sounds (2002: 394). Moreover, the results of a comparative study between Kanzi and a human child with regard to the ability to carry out novel requests showed that Kanzi had a “72%

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success rate vs. 66% for the child” (Benson and Thibault 2009: 105). The authors argue that “this indicates that he has broken through the indexical barrier to symbolism” and that “for Kanzi, like humans, the lexigrams remain indexical, but are related to each other symbolically, as they are for humans” (2009: 105). This remarkable individual, showing signs of incredible intelligence and communicative abilities compared to other conspecifics, has been at the centre of many studies and research papers, both from biological and linguistic perspectives. There are scholars who have written papers and articles about this case from a systemic functional linguistic approach, such as James D. Benson, and I will discuss some of these studies in more detail at the end of the next section.

3.3.2. SFG Approach It seems that there is one aspect in the communication of primates that appears in both vocal and gestural communication, and that is that of ‘contextual flexibility’. Call (2008) points out: “like gestures, vocalizations show an important degree of contextual flexibility when it comes to usage and comprehension” (2008: 247-249). Indeed, Cartmill and Byrne (2010) add, with regard to great ape gesturing, that:

“This contextual flexibility is characterized by the lack of a one-to-one correspondence between external events or social contexts and particular gestures, and in great apes it has been taken to imply social flexibility in achieving their aims: “disassociation of means and ends”.” (2010: 795).

The same lack of one-to-one correspondence between signal and meaning can be found in the vocalizations of vervet monkeys:

“Thus, even with vervet monkey alarm calls, there was not a consistent one-to-one mapping of signal to object, suggesting alarm calls are not simply sophisticated innate releasers but are subject to other contextual factors. Context matters and affects the meaning extracted by recipients, even if the predominant production and usage of calls is segregated by predator type.” (Snowdon 2008: 75)

The importance of contextual factors and the uneven relationship between the levels of ‘meaning’ and ‘expression’ are exactly what characterizes the stratification model. See Figure 11 for a schematic representation of the relationship between ‘meaning’ and ‘vocalizations’, and the

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influence of context in vervet monkeys, and see Figure 12 for a schematic representation of the relationship between ‘meaning’ and ‘vocalizations’, and the influence of context in Diana monkeys. Context Meaning Vocalizations

- Male or female?

- In the wild or in

captivity?

- Inside or outside

territory?

- On the ground or up in

the trees?

- …

- Signalling a predator

Which predator depends on:

• the type of call (!)

• the context (")

Alarm call

Figure 11: schematic representation of the relationship between ‘meaning’ and ‘vocalizations’, and the influence of context in vervet monkeys Context Meaning Vocalizations

- Male or female?

- High or low luminosity?

- Socio-positive or socio-

negative situation?

- …

- Signalling a predator

Which predator depends on:

• the type of call (!)

• the context (")

Alarm call

- ‘H’ call

- ‘R’ call

- ‘L’ call

- ‘A’ call

- Combination of the

abovementioned

Figure 12: schematic representation of the relationship between ‘meaning’ and ‘vocalizations’, and the influence of context in Diana monkeys In these two figures, we can notice that the contextual factors (which are represented by the outer circle in a stratification model) are indeed of major importance with regard to both the meaning of an alarm call and the way in which an alarm call is performed. Of course, one could distinguish between contextual factors that are species-specific and between factors that are related to the context of situation. For vervet monkeys, the contextual factors include whether the call is

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performed inside or outside the territory or whether it is performed high up in the trees or down on the ground (for example, depending on whether the predator is a bird that attacks from the air or a mammal that hunts on the ground). For Diana monkeys, the contextual factors include, among others, whether the call (or combination of calls) is performed inside or outside the territory, whether there is high or low luminosity, and whether the performer is part of a socio-positive or socio-negative situation. With regard to the gestural communication of chimpanzees and bonobos, I have decided to apply the stratification model to both species at once, since there is a large degree of overlap between them. According to Graham et al. (2017) the chimpanzee and bonobo repertoires seem to be pan-typical to a very considerable extent (2017: 177).

Figure 13: Stratification applied to the gestural communicative system of chimpanzees and bonobos Figure 13 represents a rather simplified overview of how the gestural communicative system of chimpanzees and bonobos looks like in general. Since chimpanzee and bonobo repertoires share a lot of commonalities, the level of expression is reduced to a ‘shared gestural repertoire’, which consists of around 60 individual gestures that are shared by both species. The meaning of each gesture is not only linked to a gesture, but it is also highly context-dependent, since a single gesture can be used in multiple contexts and multiple gestures can be used in a single context. It

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is also important to note that the species-specific context is not that different for chimpanzees and bonobos, but, of course, the context of situation has a much larger influence on the possible change in meaning in a specific gesture. For example, is the gesturing individual in a threatening situation? Is the individual in the wild or in captivity? Is there a human observing?

When we look at the metafunctions of general primate communication, it is opportune to distinguish again between the two different modalities. With regard to the ideational metafunction, the vocal communication of vervet monkeys and Diana monkeys contains mostly concrete behavioural reactions regarding possible predators, while the gestural communication of great apes displays a much larger range of meaning (both concrete and abstract ideas). This wider range of possibilities to express themselves also corresponds with their cognitive abilities. With regard to the interpersonal metafunction, we can see that interaction is the most important aspect in both modalities. In the case of vocal communication the focus lies on conveying a message to a group, rather than to one specific individual, because the auditory modality allows for a much wider spatial range. Gestural communication, however, is more focused on one-on-one interaction, because gestures have to be perceived visually, which requires that the sender and the receiver have to be close to each other. With regard to the textual metafunction, there is not much to say about concepts such as ‘coherence’ or ‘theme-rheme’, since there is no evidence for any syntactical structures in neither alarm calls, nor in gestural communication.

Finally, I have to discuss the special case of Kanzi, and how it has been studied from a linguistic perspective before. Benson and Fries et al. (2002) reinterpret the original findings of primatologist and researcher Sue Savage-Rumbaugh, who raised Kanzi and trained him to use a lexigram keyboard to communicate, from an SFL perspective. The authors propose that SFL “with its highly semanticized grammar and contextual orientation” (2002: 2) provides a theoretical foundation in order to study the way in which Kanzi uses the keyboard and to what degree evidence of symbolic language can be found. With regard to the concepts of ‘stratification’ and ‘metafunction’, they limit their study to the lexicogrammatical level and to the ideational metafunction. There is evidence that there are realisations between the different levels of stratification, and that there is a network of options on both the paradigmatic and syntagmatic axis (15-17), just as is the case with human language. For a detailed analysis of the data, I want to refer to Benson and Fries et al. (2002), but, in summary, they conclude that the data indeed suggest that Kanzi’s interpretations of communicative acts can be “based on symbolic relations between indices” and that “there is evidence that a bonobo brain can process human symbolic language […], and thus manifests some degree of human-like consciousness” (23).

Other SFL-oriented studies that were concerned with Kanzi’s communicative behaviour have been conducted, but here the emphasis rather lay on the interpersonal metafunction. In a study on “Confrontation and support in bonobo-human discourse”, also by Benson and Greaves et al.

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(2002), the conversational analysis, as well as the lexicogrammatical analysis, showed evidence that Kanzi’s language abilities had been underestimated. When Kanzi interacted with Sue Savage-Rumbaugh, he showed that he construes “a recognizable social world through discourse”, that he is “exchanging discourse roles with Sue”, and that he “negotiates the asymmetrical power relation between himself and Sue” (2002: 23-27). Also, Benson and Thibault (2009) delve deeper into the interpersonal metafunction in interaction between bonobos and humans. The authors state that “when humans and bonobos interact with each other and with their environment by means of the lexigram (among other things), the flow of their interaction is manifestly intentional and contentful” (2009: 107). Because bonobos are social and cultural beings (like humans), because they are so similar neuroanatomically and genetically, and because bonobos and humans are able to learn from each other’s actions and behaviours, Benson and Thibault (2009) suggest that “interpersonally coordinated interaction and associated conventions and norms play a key role in the explanation of enhanced cognitive and representational complexity in languaged bonobos” (2009: 111). However, in relation to the interpersonal metafunction the authors also mention what Halliday characterised as “the exchange of two ‘commodities’, viz. information and goods-&-services”. Instead of applying this idea of ‘exchange’, the authors analyse the interpersonal interaction between bonobos and humans as follows:

“[T]he embeddedness of human and bonobo behaviour in interpersonally coordinated interaction is founded on a normative cultural dynamics of self- and other-tracking and monitoring that makes use of local theories of the self as virtual narrative entities that we co-construct through our interactions along our intertwined temporal trajectories.” (Ibid.)

In conclusion, the communicative systems of primates, a species with which we share a relatively close common ancestor, are to some degree multimodal, yet a clear distinction can be made between the mainly vocal and gestural communication (in respectively monkeys and great apes). The vocal communication in vervet monkeys and Diana monkeys, for example, is rather limited in its range of meanings, since the vocalizations (such as alarm calls) are closely tied in with both the call type and the contextual factors. Gestural communication, which has a wider range of meanings (but is also very context-specific), has much more potential for abstract and even symbolic meanings, especially in the genus Pan.

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4. DISCUSSION The three case studies discussed above are all very different from each other in the biological sense, meaning that the first case study was concerned with a social insect, the second one with a variety of songbirds, and the third one with a variety of monkey and great ape species. Yet, they all share a unique system of communication, each in their own modality and each to their own cognitive abilities.

Firstly, it is important to point out some differences that can be found between the three case studies (and their systemic functional linguistic interpretation). A first difference is, of course, modality. The complex communicative dances of honeybees can by no means be compared to auditory or visual communication, such as vocalizations (food calls, alarm calls, whistles, songs, etc.) in songbirds or monkeys, or gestures in great apes. In addition to that, honeybee communication also contains a chemical component (i.e. transfer of a specific scent), which requires close contact. The whole system of dances is rather limited in the number of meanings it can produce, viz. the position of and the distance to a food source from the hive relative to the sun. Thus, honeybee communication has meaningful components that build up a message, which in its turn can be interpreted by another working bee. However, there is no conversation or dialogue possible. Gestures and especially vocalizations can be perceived over much longer distances, and the messages can contain a much larger variety of context-dependent meanings, which allow for dialogue (or ‘duetting’) in songbirds and conversations in great apes.

A second difference is to be found in the stratification model at the levels of ‘meaning’ and ‘expression’. The waggle dance of the honeybee shows a clear one-to-one correspondence between the specific components of the dance (i.e. number of waggles, number of turns, tempo of waggles, angle at which the dance is performed) and the specific meanings that are associated with each component (i.e. distance and direction towards the food source). In songbird and primate communication, however, there is no clear one-to-one correspondence between the means of expression and the associated meanings. There are two possible reasons why this is the case. On the one hand, there is an increase in cognitive abilities (from songbirds to great apes), which explains the increasing complexity in the meaning-expression relationship. On the other hand, there is the increasing importance of context and its influence on the content of an expression.

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Of course there are also some similarities that are worth mentioning. Interestingly, Marler (1961) points out a similarity between the frequency of repetition of the chaffinch’s song and the intensity and persistence of the honeybee’s dance:

“The frequency with which the chaffinch song is repeated probably conveys appraisive information to the female about the male’s relative suitability as a mate […]. Similarly the persistence of dancing in the honey bee, as expressed by the number of dances given before the sequence is broken, conveys appraisive information about the richness of the food source or the suitability of a new nest site to other members of the hive.” (1961: 267-268)

This might be interpreted as a mere coincidence or as a universal trait of all communicative systems that repetition and persistence (also in gestural communication of the great apes) are indeed meaningful in some sense. However, Miklósi (2002) warns for the overextended use of functional analogies. With regard to the communicative dances of honeybees, the author mentions:

“Nobody thinks that the bee dance informing companions about distance and direction of a food source is driven by the same behavioural/neural mechanisms used by humans when transmitting the same information using language. Nevertheless, in a sense bee dance and language can be regarded as functional analogies. The main question therefore is how far one should stretch such a comparison, given that one’s interest lies in the underlying mechanisms that govern the behaviour.” (2002: 17)

More generally, with regard to the stratification model and the applicability of the metafunctions, each communicative system is clearly unique and species-specific, yet it is remarkable that they all fit in the pattern of ‘context’, ‘semantics’, and ‘expression’ (see Figure 2 in section 2.2.3.), and all fit in the categories of the ‘ideational’, ‘interpersonal’, and ‘textual’ metafunction. Depending on the amount of cognitive skills, animals do have thoughts and mental representations of concepts (i.e. the ideational metafunction), and they are able to express them intentionally and inter-individually (i.e. the interpersonal metafunction), through whatever means of expression they have access to (i.e. the textual metafunction). Thus, it is clear that it is indeed possible to apply some aspects of SFG, a grammatical model designed for human language, to the communication systems of all the animals discussed in this paper.

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Another similarity across all the case studies is the emphasis on the importance of context. It is not only one of the key concepts in SFG, context also played a major role in the understanding of the different communicative systems in the majority of the studies related to animal communication, cognition, and behaviour that I have read and discussed.

Although SFG is a model designed for human communication, I have tried to avoid the anthropocentric and glottocentric approach as much as possible, and I have analysed the communicative acts from the bottom up, i.e. from the biological data regarding the different means of expression. Nevertheless, it is clear by now that many language-like features (Hockett’s ‘design features’ and other scholar’s attempts to classify some features as typically human) are not typically human after all; not even the capacity for symbolic thought, as the case of Kanzi the bonobo has proven. The only thing that seems to separate humans from the other species is that we have evolved to use all of the features at once and learned to express ourselves through the auditory-visual modality, which allowed for a very complex and arbitrary (yet very productive) communicative system.

Finally, I want to repeat that the selected case studies by no means represent all the complexities of the different kinds of animal communication systems. There is a whole range of species that display other interesting forms of communicative behaviour (such as pointing behaviour in dolphins, vocalizations in whales, and even lesser known forms of modalities like tactile, electric or bioluminescent communication) that are all left out of this paper because of its limited scope. Of course, everyone is free to elaborate and expand on the three different forms of animal communication systems that have been discussed in this paper, so that we can understand better how they function, analysed from the perspective of a typically human grammatical model such as SFG.

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5. CONCLUSION The study of animal communication, both from an anthropocentric and a non-anthropocentric approach, is important to gain insight in the evolutionary processes of how human language came into existence. It is also important for us to understand how non-human forms of language function, so that we can learn from it. The communicative dances of honeybees are build up from smaller components of meaning that each correspond to a particular meaning. These dances, which communicate information about the external world, are understood in the interaction taking place in the beehive. Unlike honeybees, songbirds and primates do not have a one-to-one correspondence between the levels of expression and meaning. This is the consequence of an increase in influence of species-specific and situational context, which allowed for the evolution of contextual versatility and flexibility. Primate vocalizations, such as alarm calls, show some similarities with the vocalizations of songbirds with regard to this ‘contextual flexibility’. Primate gesturing, however, is much more complex and also more intentional. In interaction with humans it even approximates human-like abstract and symbolic thought.

The three case studies show that each animal has a unique and species-specific communication system. Consequently, it is indeed possible to apply SFG concepts, such as ‘stratification’, ‘metafunctions’, and the importance of ‘context’, to different types of animal communication. The analysis shows that the degree to which these concepts can be applied to each type of communication, i.e. communicative dancing, vocalizing, and gesturing, is related to the cognitive abilities, the complexity of the communicative system, and the context (e.g. wild or captivity, human observers, stressful situations, and other circumstantial factors) in which the communicative act is performed.

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A Systemic Functional Linguistic (SFL) Approach to Animal … · 2018-08-29 · 3 ACKNOWLEDGEMENTS First and foremost, I want to thank my supervisor Prof. Dr. Miriam Taverniers for