Discussion on Theory of Human Behaviour and Interactive Systems Design

8/2/2019 Discussion on Theory of Human Behaviour and Interactive Systems Design

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U W A I S A F Z A L B M A N 3 0 7 6 0 - A D V A N C E D H C I

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Discuss the relationship between theory of human behaviour and design of

interactive systems. Use examples from three areas: Mental Models; Errors in

skilled performance; Collaborative work.

I N T R O D U C T I O N

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DEFINITIONS

Firstly, let us begin by unpacking the terms that form the backbone of this essay.

WHAT IS THEORY OF HUMAN-BEHAVIOUR?

The Theory of Human Behaviour is an umbrella term encompassing a set of theories

concerned with explaining human behaviour.

In the context of HCI, the sub-set of human-behaviour theories belonging to a branch of

Psychology known as Cognitive Psychology are especially relevant as well as those belonging

to other behavioural sciences, because they offer an insight into the man who interacts with

the machine. According to Foley (2003) Cognitive Psychology is the scientific study of

Cognition. The word Cognition is a Latin word which means of knowledgeand can be traced

back to the Ancient works of Plato and Aristotle.

Broadly speaking, Cognitive Psychology is concerned with understanding conscious and

unconscious mental activities including: sensation and perception1, learning and memory,

thinking and reasoning, attention and consciousness, imagining and dreaming, decision

making, problem solving, creativity, and intelligence (Foley, 2004). Each of these is like a

worker in the factory of information and knowledge production.

WHAT IS INTERACTIVE SYSTEMS DESIGN?

According to Sharp et al. (2007), there are many terms for Interactive Systems Design - all

represent a similar meaning, however interaction design [ID] is increasingly being accepted

as the umbrella term (p.9). Hence, what is Interaction Design?

Designing interactive products to support the way people communicate and interact

in their everyday and working lives. (Sharp et al., 2007, p.8)

1How the mind interprets information gained via. the senses, in order to make sense of the world.


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Winograd (1997) describes ID as Designing spaces for human communication and

interaction ( p.160), whilst according to Thackara (2001) it is the why as well as the how of

our daily interactions using computers (p.50).

Examples of interactive systems include Personal Computers2 (inc. software e.g.

visualisations), the web, MP3 players, Video Games Consoles, ATM to the latest in: wearable

e.g., Nike+ iPod talking shoes; sharable e.g., Microsoft Touch; Augmented and mixed reality

systems e.g., augmented maps3 (Reitmayr et al., 2005).

Now that we have clarified the terms, what is the relationship between them? The bridge

between these two terms is Human Computer Interaction (HCI) (Carroll, 2003, p.1). HCI is

about improving the relationship between man and machine. Hence, the definitions

synthesise as follows: HCI professionals employ theories of human behaviour to design better

interactive systems. HCI interests in theories of Human Behaviour can be seen as the

application of Hansons (1971) classic Admonition Know thy User.

D I S C U S S I O N O N

R E L A T I O N S H I P B E T W E E N

H U M A N B E H A V I O U R T H E O RY

& D E S I G N O F I N T E R A C T I V ES Y S T E M S

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Already the past two, almost three decades have witnessed the maturity of HCI as a scientific

discipline. Yet, there is still a long way to go4. Students and practitioners migrated from

multiple disciplines including cognitive psychology, social psychology, sociology,

anthropology, communication studies, and human-factors engineering lending their

expertise. The grounds for the development of HCIs scientific foundations were lain with the

representational theory of mind as its underlying rubric. Since the 1980s, a multi-disciplinary

body of theoretical literature has been emerging (Carroll, 2003). For example, Card, Moran,

and Newell (1983) developed the Goals, Operations, Methods, and Selection rules (GOMS)

model for analysing routine human-computer interactions. Focussing on theories of human-

2Including Laptops, Tablet PCs, and increasingly Ultra Mobile PCs.

3Paper-based maps are augmented with digital pictures and video footage to enable emergency workers to assess the

effects of flooding and traffic.4In the form of challenges, which we shall discuss later.


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behaviour - How many such theories can lead to design? We use examples from three areas to

provide an answer.

M E N T A L M O D E L S

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Mental Models can be defined as the users knowledge of how to interact with the system, and

to a lesser extent how that system works (Sharp et al., 2007, p.116). The term has entered HCI

from the door of Cognitive Psychology (Craik, 1943) which illustrates the after-emigrational

impact practitioners from other disciplines have made, as mentioned earlier. When a user

uses a system e.g., an Internet Browser, he begins to form ideas about how the system works,

how to get the system to do what he wants, and what to do when something unexpected

happens, and to achieve this he may transfer his experience of using (perceived) similar

interfaces across; all this is assumed to be the mental model (Sharp et al., 2007). The more

the user learns about the internet browser and how it functions, the more developed his

mental-model of it. According to Sharp et al. (2004), using incorrect mental models to guide

behaviour is common, for instance, some elevator users will press the call button multiple

times. When asked why? One reason given is that it ensures the elevator will arrive. On the

other hand, this could sometimes be out of impatience. Norman (1983a) identified that most

peoples understanding of interactive systems e.g., search engines is poor. Their mental-

models are often incomplete, based on incorrect analogies, and are superstitious.

Consequently, they struggle to articulate what is happening, and how to solve problems

effectively.

Ideally users should be able to develop mental models that match an interactive systems

conceptual model5. However, HCI researchers have noted that most users are resistant to

spending a long time learning (Sharp et al., 2007). Alternatively, by understanding/theorizing

the way users develop mental models, transparentsystems that support and are in-sync with

users way of thinking may be designed. An experiment conducted by Cockburn and Jones

(1996) illustrates this potential. They investigated mental models of the back and forward

facility provided by web-browsers6 and found most users had an incorrect understanding. The

facility works by maintaining a history of all the pages visited. The back and forward buttons

allow users to navigate pages stored in the history list. Alternatively pages can be selected

from the history dialogue box. All is well when the back and forward buttons are used to cycle

5 The way a system is intended to be used by its designers. Conceptual models are devised as tools for the

understanding or teaching of physical systems. Mental models are what people really have in their heads and what

guides their use of things (Norman, 1983, p.12).6This also applies to Microsoft Windows Explorer.


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through pages in the history list, however something contrary to most users understanding

takes place when a page (X) is selected from a history list, followed by visiting a new URL. The

pages above page X are popped from the history list and the new page is added to the top of

the history list (in their place). So that when the back or forward button is pressed, the pagethe user expected to appear doesnt appear. This can be explained by the fact that browser

historys function as - what are known as - arrays/stacks in programming. They follow a Last

in First Out (LIFO) data structure, which is often likened to a stack of plates. The undo-redo

facility in word-processors works along the same lines.

A study into users models of the copy buffer in word-processors conducted by Payne et al.

(1990), further exemplifies design implications of mental-models research. Participants were

given copy and paste tasks e.g., copying a string of text into two separate locations. Payne et

al. observed many novice users copying the same string twice, when there was only need to

copy the string once, and then pasting it twice into two separate locations. This was because

the copy command didnt intuitively or transparently transfer its ability into the novice users

mental model. To demonstrate this, Payne et al. found that by re-naming copy as store,

more novice users were inclined to construct the intended understanding.

Payne (1991) conducted study into user mental models of ATMs (p.140). He discovered his

student-participants wrongfully assumed the ATM encoded the bank-balance onto the card;

others thought the only information on the card was the PIN; models of the ATM were not

comprehensive, they were fragmentary, consisting of collections of beliefs about parts of the

system. Students would employ analogies to explain parts of the system which bore no

relation to the whole. Almost all of his participants believed it was impossible to type ahead

during machine pauses. Consequently, some transactions went on for longer than was needed.

Hence, some mental-models caused inefficient behaviour.

Whilst the aforementioned studies demonstrate clear design implications of mental model

research, there are other studies for which it is difficult to see a relationship between mental-

models theory and design. E.g., mental models as Homomorphisms - reflecting the structure

of the world they represent, just as a photograph reflects the structure of that which it is a

photo of (Payne, 2003).

So why doesnt theory always lead to design? This a question not exclusive to HCI, but one

that has faced modern science since the beginning. Perhaps, the answer that science has

provided, is the same answer. Science has can be divided into basic science - scientists

pursuing research mainly to satisfy their intellectual thirst and applied science - application

of research for practical or profitable gain. Sometimes an obvious relationship doesnt exist

between the two however as time go by, a relationship emerges for example superconductivitywas nothing more than a laboratory curiosity for Dutch physicist Onnes when he discovered it


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in 1911. Yet, nowadays superconductive magnets are used in applications ranging from

diagnostic medical equipment to particle accelerators (Burnie, 2003).

It can be argued that a designers creativity suffices, and that painstaking research isunnecessary. In contrast, it can be argued that even when theories dont seamlessly lead to

design, theorizing should continue as part of the quest for knowledge. However Dix et al.

(2004) argue for a middle path to be drawn one that combines that strength ofArt and of

Science. The truth is that HCI is required to be both craft and a science to be successful

(p.6). Hence, a marriage between the creative flare of art and the rational explanations of why

some things are successful whilst others arent of science is suggested.

E R R O R S I N S K I L L E D P E R F O R M A N C E

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Thus far, we have presented examples mentioning novice users carrying incorrect mental-

models. Hanson, Kraut and Farber (1984)conducted studies with intermediate-expert users

performing document processing and e-mail tasks in UNIX and found even experts make

errors. They logged over 10,000 UNIX commands revealing an overall error rate of 10%.

Not only can errors lead to serious mishap but they also carry social repercussions like

causing frustration to novice users (Norman, 1983). Errors have been attributed to slips

(unintentional mistakes, where the user intends and knows what to do, but does the wrong

thing for some reason (Norman, 1981)) misconceptions (mistakes due to the user

possessing incorrect or incomplete knowledge) (Reason, 1990) and post-completion

errors (Byrne and Bovair, 1997) which are described as errors which occur during tasks that

require an extra action to be performed after the main goalhas been satisfied e.g., leaving the

original document in a photo-copier after retrieving the copied documents; leaving change in

a vending machine after retrieving the chocolate; leaving a card in an ATM after retrieving

cash; or leaving car headlights on. Such errors have been observed to occur amongst tasks

with a similar task structure. They are said to be persistent, in that they do not diminish with

experience (Blandford, 2000). What differentiates post-completion errors from slips and

misconceptions is that they are performed by people who have the knowledge and the

experience to carry out the task

According to (Blandford, 2000) post-completion errors have received little attention in the

psychology or design literature. According to Byrne and Bovair (1997), post-completion errors

are best explained by the users working memory load. The error will be made when workingmemory load is high, but not when it is low. Lab experiments have empirically demonstrated


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that such errors are indeed due to constraints on working memory-load (Byrne and Bovair,

1997).

Such theorizing and experimentation on errors has seamlessly lead to reflection over theirdesign implications. Norman (1983b) analyzed a set of slip errors, breaking them into

classifications. In trademark fashion, he then went onto develop principles of system design

intended to minimize slip errors and their effects. For instance Normans principles included

consistency7 of the system in structure and design to minimize memory problems in

retrieving operations. Actions should be reversible where possible, where they cant be they

should be difficult to do thereby preventing unintentional action. An example of this is the

undo facility and the confirm dialog box. However, Norman recognized that applying theory

can be difficult, hence he suggested that designers make trade-offs.

Blandford (2000) present Youngs (1994) scenario in which a user has two windows open. In

one he is composing a message, a short while later, he summons another window in which he

views a time-table. Without activating the message window, he continues typing. Obviously,

his typing is of no avail. Blandford (2000) classifies this as a post-completion error. One

solution is to fizzle/fade out the borders of inactive windows (Barnard et al., 1994). This will

cause users to learn to easily identify inactive windows. Nowadays a similar sort of application

is found in Windows Vista.

Byrne & Davis (2006) conducted some lab experiments which demonstrated a significant

reduction of error rate caused by a simple design change; alteration of when feedback about

goal completion occurred, in other words restructuring the task so that the main-goal is the

last goal to be achieved. This is the solution that Blandford (2000) propose for post-

completion errors on vending machines. Similarly, in their discussion of design implications,

Byrne and Bovair (1997) suggested designers of interactive systems should avoid building

post-completion structure into the interaction, even where demands on working-memory load

are light, since peoples memory can easily become filled with task-irrelevant information like

day-dreaming. Nowadays ATMs eject the card before cash. Similar advice is offered in the

cognitive walk-through approach (Polsen et al, 1992).

7Others are Feedback and Similarity of response sequences (p.257).


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C O L L A B O R A T I V E W O R K

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Although collaborative work occurs in many different contexts e.g., school, online-gaming or

even during a conversation (Sharp et al., 2007). For purposes of clarity, we shall limit

ourselves to the work-place. Nowadays, the modern work-place relies heavily on people

belonging to inter-dependant teams spread locally and globally. For instance, (Cummings,

2001) example of a large telecommunications software system being built by a teams spread

across North America, Europe and Asia. In, HCI, CSCW is concerned with building tools to

help collocated and distributed groups accomplish their work more effectively. Collaborative

work although fruitful poses subtle challenges e.g., Karau & Williams (1993) found people

work less hard in teams than individually. According to Kraut (2003) theories of Social

Psychology can be recruited to explain what makes groups effective, what undermines them,

what makes distributed teams perform poorer than collated ones, and what is needed to

support them (Cramton, 2001). The empirical descriptions of group behaviour and the

identification of causal mechanisms that influence it provided by social scientists can

potentially inform design.

Let us take, the theory of social loafing, first observed by Ringelmann (cited in Kravitz &

Martin, 1986). The phenomena is: individuals typically work less hard when they are part of a

group than when they are on their own. It occurs when individuals believe the outcomes of

their efforts are being pooled in with efforts of group members (Kraut, 2003, p.341).

Although social loafing varies between tasks and groups, it is claimed social loafing lessens if

the individual:

is working in an attractive group* thinks his or her contribution is unique* thinks other members will perform poorly* output is visible to the group is a woman is a child raised in an Asian culture

According to Karau and Williams (1993) who developed an integrated theory of social loafing,

individuals will work harder when they think their effort leads to a valued outcome. Karau

and Williamss model predicted the asterisk-factors above as motivating individuals to work

harder. The implication of this theory for design can be demonstrated if we take group-

brainstorming tools as an example; if social-loafing is responsible for production loss, then

enforcing anonymity would be counter-productive since according to the theory, the visibility

of the individuals output is a positive factor. Another design implication exists for onlinediscussion groups: Karau and Williams (1993) tabulated a number of design ideas informed


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by their research e.g., mix novice and experts within a single group, making expertise more

essential, hence an individual will be prompted to contribute due to expecting other members

to perform poorly.

C H A L L E N G E S

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For this potential of theory informing design to be fully realised, some challenges exist.

According to Carroll (2003). They include fragmentation: too many theories and domains

exist within HCI. It isnt possible to maintain breadth and depth (Kraut, 2003);

HCI researchers are insulating themselves hence slowing multi-disciplinary progress; The

practice of HCI research and application is constrained by real world software development

which is constrained by schedule, budget, interoperability and compatibility. According to

Carroll, this has exerted pressure to streamline methods & techniques so that they can be

taught quickly. Naturally, this shrinkage leads to discarding HCI Researchs full potential i.e.,

some potential is left behind the curtain.

Hence solutions to the challenge are: one, giving HCI researchers freedom to articulate their

research so it is used in the manner they intend. Of course there will be room for feedback and

iteration. Two, synthesising a comprehensive and coherent methodological framework.

Three, giving new-generation students an appreciation of the scientific foundation

underlying HCI, so they can contribute to multi-disciplinary progress

C O N C L U S I O N

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We conducted our discussion of the relationship between theory and design by way of

providing examples drawn from the areas of mental models, errors in skilled performance,

and collaborative work. These we supplemented with examples drawn from other areas. We

demonstrated where theory has led to design, and where it isnt. This led us to a juncture

wherein we initiated a discussion on the reasons behind why theory doesnt always seamlessly

lead to design. We presented a bi-lateral argument, and Dix et al. (2003) reconciling view of

taking the middle ground: that HCI is required to be both an Art and a Science to be fruitful.

In addition, Carroll (2003) holds, the demographics of there being more practitioners than

researchers is a reflection of the success HCI is experiencing. Nevertheless, there are

challenges or obstacles rather which are hindering the potential for theories to inform design-

these HCI must overcome, namely scientific fragmentation, researchers working in isolation,

and pressure from the engineering industry.


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Discussion on Theory of Human Behaviour and Interactive Systems Design