Auditory Word Recognition
• Clearly, we use top-down processing
• The acoustic signal alone is often just not enough
– Record people saying:
• Predictable:
A stitch in time saves nine.
• Unpredictable: The next number will be nine.
– The nine spliced out of the predictable context is often
unintelligible in isolation
• So, people use context
– How and when???
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Phoneme Restoration
• Replace one phoneme in an utterance with noise
– If the phoneme is predictable from context, people
“hear” the missing sound (e.g., legi*lature)
– If tell them a sound has been replaced, they’re not
accurate at identifying which sound it is
– Warren & Warren (1970)
• Stimuli (acoustically identical except for last word)
–
–
–
–
It was found that the *eel
It was found that the *eel
It was found that the *eel
It was found that the *eel
was on the orange.
was on the axle.
was on the shoe.
was on the table.
• People believed they had heard the phoneme that
made sense given the final word
– Final word can’t have influenced what they heard at *eel
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Zwitserlood (1989)
(Tests predictions of Cohort Model - Zwitserlood was
Marslen-Wilson’s student & this was her dissertation)
• Cohort Model framework
– How much information is retrieved about all the
activated cohort members (=competitors)
before selection?
– How early in word recognition does context
influence processing?
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Possible Timecourse of Context Effects
From Zwitserlood (1989)
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Methods
• People heard sentences that ended with a critical word
(e.g., kapitein)
– Critical words had clear competitors before their uniqueness
point (e.g., kapit^aal)
• At one of several timepoints during the critical word, a
visual word that was semantically related to either the
critical word or its competitor (e.g., schip or geld)
appeared on screen
– Task = lexical decision
– Cross-modal priming paradigm
• Use response to target to tap into processing of prime
– Early test points intended to determine how early context can
rule out inconsistent competitors
– Test points determined separately for each critical word by
results of gating study
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Stimuli
• Gating study
– People heard successively longer fragments of critical words
– In 3 kinds context
• Carrier phrase: The next word is kapitein.
• Neutral context: They mourned the loss of their kapitein.
• Biasing context: With dampened spirits the men stood around the grave. They
mourned the loss of their kapitein.
• Control context: The player got the ball and scored the winning goal.
– Guessed what the word was
– Recognition point = Point in word where everyone identifies it as
the critical word
• Often earlier than uniqueness point
• How much earlier typically depends on degree of contextual constraint
– Get to see what competitors are produced before recognition point
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Visual Probe Positions
(for each critical word)
Isolation point = Timepoint in word when the critical word first given as a
response by a participant & after which it’s the only
response for that participant (mean across participants)
1.
Isolation point in Biasing Context (Mean = 133 msec; lexical access)
2.
Isolation point in Neutral Context (Mean = 199 msec; lexical access)
3.
Isolation point in Carrier Phrase (Mean = 278 msec; selection)
4.
Recognition point in Carrier Phrase (Mean = 410 msec; integration)
Probes = schip or geld
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Results
Probe positions 1 & 2
-Probes related to both
Critical Word & Competitor
primed by hearing some of
Critical word, compared to
Control condition
Here’s where enough
of word heard to start
choosing target over
competitor
Probe position 3
- Hear enough word that target
more active than competitor in
Carrier Phrase (= selection)
- Only then does Biasing
Context have an effect
Here’s also where
biasing context first
starts to have effect
-So, context does not influence
word recognition until enough
bottom-up information to start
selecting word from cohort
schip
geld
133
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199
278
From Zwitserlood (1989)
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410
Conclusions
• The results of this study led to the revision of
the Cohort Model such that context effects can
only come in relatively late
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Allopenna, Magnuson, & Tanenhaus (1998)
Tests predictions of TRACE Model
• An important difference between Cohort & TRACE models
– Difference in degree of constraint provided by word onsets
compared to rest of word is bigger in Cohort Model
– Previous work had not found any clear effects of competitors
that didn’t share onsets
• Allopenna et al. tested this by including competitors that
shared onsets vs rhymes
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Stimulus Words
From Allopenna et al., 1998
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Results of running simulations for
these items in TRACE Model
Rhyme competitor
“speaker” becomes
almost as active as
cohort competitor
“beetle”, though
later of course
From Allopenna et al., 1998
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Methods
- Instructions: “Point to the …”
-Display contains:
- Target beaker
- And at least one of:
- Cohort competitor beetle
- Rhyme competitor speaker
- Unrelated word carriage
-Participants wore head-mounted
eyetracker
- People tend to look at objects
that are mentioned
- especially before reaching for them
- How quickly do they look at the
objects related to the target word?
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Predicted fixation probabilities
based on TRACE simulations
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Fixation Probability Results
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Comparison of data to model predictions
Target & Cohort Competitor
Target & Rhyme Competitor
Model slightly overpredicts fixations to Target & slightly underpredicts fixations to
both Cohort & Rhyme competitors
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Gating Study
TRACE Model Predictions
Object choice (pointing) data
- Maybe results of first experiment specifically due to having competitor objects visually present?
- What would happen in a task using same display but that emphasizes auditory word onsets?
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Gating Study – Fixation & Pointing Results
Model vs Fixation data
Model vs Pointing data
- So, it’s not the presence of the visual object with competitor names that led to the
results in Experiment 1
- Experiment 1 provided the first clear evidence of activation of Rhyme competitors
- which lends support to the TRACE Model over the Cohort Model
- & which led to further revision of the Cohort Model
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