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Main Topic
• Listeners as active participants in comprehension process
• Model system: word recognition
Outline
1. Speed & Robustness of Lexical Access
2. Active Search
3. Evidence for Stages of Lexical Access
4. Autonomy & Interaction
Outline
1. Speed & Robustness of Lexical Access
2. Active Search
3. Evidence for Stages of Lexical Access
4. Autonomy & Interaction
The mental lexicon
sport figure
sing door carry
turf turtle gold turk turkey
turn
water turbo turquoise
turnip turmoil
How do we recognize words?
• The Simplest Theory
– Take a string of letters/phonemes/syllables, match to word in the mental lexicon
– (That’s roughly how word processors work)
• …is it plausible?
Word Recognition is Fast
• Intuitively immediate - words are recognized before end of word is reached
• Eye-tracking studies indicate effects of access within 200-300ms
• Speech shadowing at very brief time-lags, ~250ms (Marslen-Wilson 1973, 1975)
Marslen-Wilson 1975
Speech shadowing involves on-line repetition of a speaker…Speech shadowing involves on-line repetition of a speaker…
Shadowing latency
250-1000ms
The new peace terms have been announced…
They call for the unconditional surrender of …universe of …already of …
normalsemanticsyntactic
“If the interaction between higher and lower levels of of analysis takes place only after the initial phonetic and lexical identification of the word, then restoration of disrupted words should be equally frequent in all Context conditions. The shadower would have no basis, in his initial repetition, for rejecting contextually anomalous restorations. However, if immediate identification does interact on-line with the semantic and syntactic context, then it becomes possible for context variables to determine word restoration frequency.” (Marslen-Wilson, 1975, p. 226)
“The high incidence of WR errors in Normal2 illustrates the speed and the precision with which structural information can be utilized. If the first syllable indicates a word that matches the context, then the close shadower can immediately start to restore that word in his repetition. This implies, first, that the constraints derived from the preceding items of the string are available to guide the analysis of even the first syllable of the target word. Second, these constraints can specify the permissible form-class and meaning of the target word with sufficient precision to enable the shadower to assess the appropriateness of just its first syllable.” (Marslen-Wilson 1975, p. 227).
Lexical Access is Robust
• Succeeds in connected speech
• Succeeds in fast speech
• Survives masking effects of morphological affixation and phonological processes
• Deleted or substituted segments
• Speech embedded in noise
But…
• Speed and robustness depends on words in context
sentence --> word context effects
• In isolation, word recognition is slower and a good deal more fragile, susceptible to error
• …but still does not require perfect matching
Questions
• How does lexical access proceed out of context?
• Why is lexical access fast and robust in context?
• When does context affect lexical access?
– does it affect early generation (lookup) processes?
– does it affect later selection processes?
Looking for Words
• List 1sicklecathartictorridgregariousoxymoronatrophy
• List 2parabolaperiodontistpreternaturalpariahpersimmonporous
Looking for Words
• List 1sicklecathartictorridgregariousoxymoronatrophy
• List 2parabolaperiodontistpreternaturalpariahpersimmonporous
Speed of look-up reflects organization of dictionary
Looking for Words
• Semantically Related Word Pairsdoctor nursehand fingerspeak talksound volumebook volume
Looking for Words
• In a lexical decision task, responses are faster when a word is preceded by a semantically related word
• DOCTOR primes NURSE
• Implies semantic organization of dictionary
Outline
1. Speed & Robustness of Lexical Access
2. Active Search
3. Evidence for Stages of Lexical Access
4. Autonomy & Interaction
Active Recognition
• System actively seeks matches to input - does not wait for complete match
This allows for speed, but …
Cost of Active Search…
• Many inappropriate words activated
• Inappropriate choices must be rejected
• Two Stages of Lexical Accessactivation vs. competitionrecognition vs. selectionproposal vs. disposal
The mental lexicon
sport figure
sing door carry
turf turtle gold turk turkey
turn
water turbo turquoise
turnip turmoil
The mental lexicon
sport figure
sing door carry
turf turtle gold turk turkey
turn
water turbo turquoise
turnip turmoil TURN
Automatic activation
TURN
sport figure
sing door carry
turf turtle gold
turk turkey
water turn
turbo turquoiseturnip turmoil
Lateral inhibition
TURN
sport figure
sing door carry
turf turtle gold
turk turkey
water turn turbo turquoise
turnip turmoil
What is lexical access?
time
leve
l of
activ
atio
n
resting level
TURN
Stimulus: TURN
TURNIP
TURFTURTLE
Activation Competition Selection/Recognition
(e.g. Luce et al. 1990, Norris 1994)
Evidence for Cohort Activation
KAPITEIN KAPITAAL
KAPIT…
BOOT
GELD
KAPITEIN
BOOT
GELD
(Marslen-Wilson, Zwitserlood)
Evidence for Cohort Activation
CAPTAIN CAPTIVE
CAPT…
SHIP
GUARD
CAPTAIN
SHIP
GUARD
(Marslen-Wilson, Zwitserlood)
Cohort Model
• Partial words display priming properties of multiple completions: motivates multiple, continuous access
• Marslen-Wilson’s claims
– Activation of candidates is autonomous, based on cohort only
– Selection is non-autonomous, can use contextual info.
• How, then, to capture facilitatory effect of context?
Gating Measures
• Presentation of successive parts of words
– S
– SP
– SPI
– SPIN
– SPINA…
• Average recognition times
– Out of context: 300-350ms
– In context: 200ms(Grosjean 1980, etc.)
Word Monitoring
• Listening to sentences - monitoring for specific words
– Mean RT ~240ms
– Identification estimate ~200ms
• Listening to same words in isolation
– Identification estimate ~300ms
(Brown, Marslen-Wilson, & Tyler)
Cross-Modal Priming
The guests drank vodka, sherry and port at the reception
(Swinney 1979, Seidenberg et al. 1979)
Cross-Modal Priming
The guests drank vodka, sherry and port at the reception
WINE
SHIP
(Swinney 1979, Seidenberg et al. 1979)
Cross-Modal Priming
The guests drank vodka, sherry and port at the reception
WINE
SHIP
(Swinney 1979, Seidenberg et al. 1979)
Cross-Modal Priming
The guests drank vodka, sherry and port at the reception
WINE
SHIP
(Swinney 1979, Seidenberg et al. 1979)
Cross-Modal Priming
The guests drank vodka, sherry and port at the reception
WINE
SHIP
(Swinney 1979, Seidenberg et al. 1979)
Generation and Selection
• Investigating the dependence on ‘bottom-up’ information in language understanding
• ‘Active’ comprehension has benefits and costs
– Speed
– Errors
– Overgeneration entails selection
• Sources of information for generating candidates
– Bottom-up information (e.g., lexical cohorts)
– ‘Top-down’ information (e.g., sentential context)
– Questions about whether context aids generation or selection
CMLP - Qualifications
• Multiple access observed– when both meanings have roughly even frequency
– when context favors the lower frequency meaning
• Selective access observed– when strongly dominant meaning is favored by context
(see Simspon 1994 for review)
• Context vs. frequency
– The guests drank wine, sherry, and port at the reception.
– The violent hurricane did not damage the ships which were in the port, one of the best equipped along the coast.
Frequency in Reading
• Rayner & Frazier (1989): Eye-tracking in reading
– measuring fixation durations in fluent reading
– ambiguous words read more slowly than unambiguous, when frequencies are balanced, and context is unbiased
– unbalanced words: reading profile like unambiguous words
– when prior context biases one meaning• dominant-biased: no slowdown due to ambiguity
• subordinate-biased: slowdown due to ambiguity
• contextual bias can offset the effect of frequency bias
– how can context boost the accessibility of a subordinate meaning?
Speed of Integration
• If context can only be used to choose among candidates generated by cohort…
– context can choose among candidates prior to uniqueness point
– but selection must be really quick, in order to confer an advantage over bottom-up information
– [… or recognition following uniqueness point must be slow in the absence of context.]
Why multiple/selective access?
• How could context prevent a non-supported meaning from being accessed at all?
(Note: this is different from the question of how the unsupported meaning is suppressed once activated)
• Possible answer: selective access can only occur in situations where context is so strong that it pre-activates the target word/meaning
Cross-Modal Lexical Access
• Seidenberg, Tanenhaus, Leiman, & Bienkowski (1982)
– Cross-modal naming
– They all rose vs. They bought a rose Probes: FLOWER, STOOD
– Immediate presentation: equal priming; 200ms delay: selective priming
• Prather & Swinney (1977): similar w/ cross-modal lexical decision
• Tanenhaus & Donnenworth-Nolan (1984): similar, w/ extra delay in presenting target word
Summary so far
• Accounting for single vs. multiple access findings in context
• How to relate context to lexical retrieval processes
• (Non-)effects of syntactic category constraints
Electrophysiology of Sentence Comprehension
• Semantic anomaly
N400
I drink my coffee with cream and sugarI drink my coffee with cream and socks
Kutas & Hillyard (1980)
N400
(Kutas & Federmaier 2000)
‘baseball’ is not at all plausible here, yet it elicits a smaller N400 - why?
Ultra-fast Syntactic Analysis
(Friederici et al., 2000)
• Puzzle…
– As fast or faster than word recognition
– Leaves almost zero time for syntactic analysis!
– Elicited by a subclass of errors
– Localizes to Ant. Tpl. Regions and Broca’s Area
Early negativity
(Hahne et al., 2002)
1500ms
• Ultra-Fast Analysis
Electrophys. studies show responses to some syntactic errors within 150-250ms after word onset - Early Left Anterior Negativity, ELAN
– John criticized Max’s proof of the theory.– John criticized Max’s of proof the theory.
(Neville et al., 1991)
Ultra-fast Syntactic Analysis
• Suggestion: fastest analysis occurs when structure is built before word is seen in input
• Fastest responses reflect mismatch, when incoming word mismatches predicted category
NP
Max’s N
criticized
of
FT7
1000ms
With prediction
Without prediction
(Lau, Stroud, Plesch, & Phillips, 2006)
• Test case: same error, varying prediction
Although John criticized Bill’s data, he didn’t criticize Max’s.
a. Although John criticized Bill’s data…
…he didn’t criticize Max’s of proof the theory.
b. Although John criticized Bill…
…he didn’t criticize Max’s of proof the theory.
Frequency in Object Recognition
X
bench
bed
bell
lobster
“Pick up the be..” (Dahan, Magnuson, & Tanenhaus, 2001)
Frequency in Object Recognition
• Timing estimates
– Saccadic eye-movements take 150-180ms to program
– Word recognition times estimated as eye-movement times minus ~200ms
Cohort Model
• Partial words display priming properties of multiple completions: motivates multiple, continuous access
• Marslen-Wilson’s claims
– Activation of candidates is autonomous, based on cohort only
– Selection is non-autonomous, can use contextual info.
• How, then, to capture facilitatory effect of context…
Evidence for Cohort Activation
CAPTAIN CAPTIVE
CAPT…
SHIP
GUARD
CAPTAIN
SHIP
GUARD
(Marslen-Wilson, Zwitserlood)
Matches to other parts of words
• Word-ending matches don’t prime
– honing [honey] bij [bee]woning [apartment]foning [--]
Disagreements
– Continuous activation, not limited to cohort, as in TRACE model (McClelland & Elman, 1986)
– Predicts activation of non-cohort members, e.g. shigarette, bleasant
Non-Cohort Competitors
(Allopenna, Magnuson, & Tanenhaus, 1998)
“Pick up the…”
beaker
beetle (onset)speaker (non-onset)carriage (distractor)
Non-Cohort Competitors
(Allopenna, Magnuson, & Tanenhaus, 1998)
“Pick up the…”
beaker
beetle (onset)speaker (non-onset)carriage (distractor)
Non-Cohort Competitors
(Allopenna, Magnuson, & Tanenhaus, 1998)
“Pick up the…”
beaker
beetle (onset)speaker (non-onset)carriage (distractor)
I wanted to point out a minor difference in your interpretation of Allopenna, Magnuson, & Tanenhaus (1998) and mine. Allopenna et al. is cited on p. 75 as one of the "estimates in the literature [that] the earliest processes involved in lexical access often fall in the 200 ms range". But eye tracking data of the sort we presented actually gives a strikingly different estimate. What we find again and again in studies using the visual world paradigm is that there is an approximately 200-250 ms lag between events in the speech signal and changes in fixation proportions. However, this should not suggest that it takes 200 ms for processes of lexical access to kick in. Rather, given that it takes at least about 150 ms to plan and launch an eye movement to a point of light in a darkened room, this means we can roughly subtract 150 msecs of the lag and attribute it to saccade planning. This leaves us with only about 50 msecs to attribute to the very earliest processes of access that are indexed by the eye movements. (This seems too short by 1-2 dozen msecs, but note that only a very small proportion of trials include such early eye movements, and statistically reliable differences between related and unrelated items emerge another ~25-50 msecs later.)
[Email message, 6/26/07]
Jim Magnuson, UConn
Outline
1. Speed & Robustness of Lexical Access
2. Active Search
3. Evidence for Stages of Lexical Access
4. Autonomy & Interaction
Lexical access involves
1. Activation of lexical representations• including activation of representations
matching the input, and• lateral inhibition between activated
representations
2. Followed by selection or decision• involving competition among activated
representations that are similar in form
MEG response components elicited by visually presented words in the lexical decision task
RMS analysis of component field patterns.
Neighbors & Competitors
• Phonotactic probability– sound combinations that are likely in English– e.g. ride vs. gush
• Neighborhood density– number of words with similar sounds– ride, bide, sighed, rile, raid, guide, died, tried,
hide, bride, rise, read, road, rhyme, etc.– gush, lush, rush, gut, gull …
RT
Behavioral evidence for dual effects
• Same/different task (“low-level”) RTs to nonwords with a high phonotactic probability are speeded up.
• Lexical decision task (“high-level”)RTs to nonwords with a high phonotactic probability are slowed down!
High probability: MIDE
YUSH RT
RT MIDE
YUSH RT
Low probability:
High probability:
Low probability:
Sublexicalfrequency effect
(Vitevich and Luce 1997,1999)
Competition effect
Stimuli
High probability Low probability
Word BELL, LINE PAGE, DISH
Nonword MIDE, PAKE JIZE, YUSH
• Materials of Vitevich and Luce 1999 converted into orthographic stimuli.
• Four categories of 70 stimuli:
• High and low density words frequency matched.
(Pylkkänen, Stringfellow, Marantz, Brain and Language, 2003)
Effect of probability/density (words)
100
200
300
400
500
600
700
M170 M250 M350 RT
HighProbWord LowProbWord
n.s.
n.s.
**
*
(Pylkkänen, Stringfellow, Marantz, Brain and Language, 2003)
Effect of probability/density (nonwords)
0
100
200
300
400
500
600
700
800
M170 M250 M350 RT
HighProbNonword LowProbNonword
n.s.n.s.
*
**
(Pylkkänen, Stringfellow, Marantz, Brain and Language, 2003)
M350 = 1st component sensitive to lexical factors but not affected by competition
time
leve
l of
activ
atio
n
resting level
TURN
TURNIP
TURFTURTLE
Activation Competition Selection/RecognitionM350
Stimulus: TURN
NURSEDOCTOR
DINRUP
COUCH
NURSE
NURSE
Semantic association facilitation [consistent]No association inhibition [sometimes]
Controlled/strategic effectsLong SOA (Stimulus Onset Asynchrony), e.g. > 500msExplicit pairing of wordsHigh proportion of associated pairs
High ambig: The shell was fired towards the tank.Low ambig: Her secrets were written in her diary.
Rodd, Davis, & Johnsrude, 2005, Cereb. Cortex