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9/8/10 Psyc / Ling / Comm 525 Fall 10
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???
9/8/10 Psyc / Ling / Comm 525 Fall 10
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 was on the orange.– It was found that the *eel was on the axle.– It was found that the *eel was on the shoe.– It was found that the *eel 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
9/8/10 Psyc / Ling / Comm 525 Fall 10
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?
9/8/10 Psyc / Ling / Comm 525 Fall 10
Possible Timecourse of Context Effects
From Zwitserlood (1989)
9/8/10 Psyc / Ling / Comm 525 Fall 10
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
9/8/10 Psyc / Ling / Comm 525 Fall 10
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
9/8/10 Psyc / Ling / Comm 525 Fall 10
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
9/8/10 Psyc / Ling / Comm 525 Fall 10
Here’s where enough of word heard to startchoosing target overcompetitor
Results
From Zwitserlood (1989)
Probe positions 1 & 2-Probes related to both Critical Word & Competitor primed by hearing some of Critical word, compared to Control condition
Probe position 3- Hear enough word that target more active than competitor in Carrier Phrase (= selection) - Only then does Biasing Context have an effect
-So, context does not influence word recognition until enough bottom-up information to start selecting word from cohort
133 199 278 410
schipgeld
Here’s also where biasing context first starts to have effect
9/8/10 Psyc / Ling / Comm 525 Fall 10
Conclusions
• The results of this study led to the revision of the Cohort Model such that context effects can only come in relatively late
9/8/10 Psyc / Ling / Comm 525 Fall 10
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
9/8/10 Psyc / Ling / Comm 525 Fall 10
Results of running simulations for these items in TRACE Model
From Allopenna et al., 1998
Rhyme competitor“speaker” becomesalmost as active ascohort competitor“beetle”, thoughlater of course
9/8/10 Psyc / Ling / Comm 525 Fall 10
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?
9/8/10 Psyc / Ling / Comm 525 Fall 10
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
9/8/10 Psyc / Ling / Comm 525 Fall 10
Gating StudyTRACE 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?
9/8/10 Psyc / Ling / Comm 525 Fall 10
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