Tracking the timecourse of Tracking the timecourse of multiple context effects in multiple context effects in assimilated speech assimilated speech David Gow Massachusetts General Hospital Bob McMurray Dept. of Brain and Cognitive Sciences University of Rochester With thanks to Dana Subik, Joe Toscano & John Costali
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Tracking the timecourse of multiple context effects in assimilated speech
Tracking the timecourse of multiple context effects in assimilated speech. Bob McMurray Dept. of Brain and Cognitive Sciences University of Rochester. David Gow Massachusetts General Hospital. With thanks to Dana Subik, Joe Toscano & John Costalis . Laboratory Phonology. - PowerPoint PPT Presentation
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Tracking the timecourse of Tracking the timecourse of multiple context effects in multiple context effects in
assimilated speechassimilated speech David Gow
Massachusetts General HospitalBob McMurray
Dept. of Brain and Cognitive SciencesUniversity of Rochester
With thanks to Dana Subik, Joe Toscano & John Costalis
Overview
2) Coping with Coronal-Place Assimilation during online recognition.
Laboratory Phonology Spoken Word Recognition
1) Bridging fields yields:New solutions to old problems.New questions.
3) Implications for language processing & phonology.
Laboratory Phonology: How perceptual and articulatory constraints drive sound change and shape phonological systems
Bridging Fields: Laboratory Phonology
Rich information source in the signal: Constraints inferred through acoustic and articulatory measures.
Do phonological constraints inform word recognition?Can details of word recognition inform phonological constraints?
Perceptual models tend to come in two varieties:
Bridging Fields: Spoken Word Recognition
Spoken word recognition models that assume phonemic inputs as input to the lexicon and meaning.
Ignore systematic acoustic variation.
Phoneme perception models that relate acoustic properties to categorical perception
VOT0
100
PB
% /p/
ID (%/ pa/ ) 0
100Discrimination
Discrimination
VOT0
100
PB
% /p/
ID (%/ pa/ ) 0
100Discrimination
VOT0
100
PB
% /p/
ID (%/ pa/ ) 0
100
VOT0
100
PB
% /p/
ID (%/ pa/ ) 0
100
0
100Discrimination
Discrimination
Limits of categorical perception
Categorical perception (CP) is task-dependent, and doesnot appear to take place in tasks that involve spontaneous, naturalistic speech understanding.
McMurray, Aslin, Tanenhaus, Spivey & Subik (in prep)
Within category variation that should be lost in CP affectslexical processes
greem beans green (Gaskell & Marslen-Wilson, 1996; Gow, 2001)
cap box cat (Gaskell & Marslen-Wilson, 2001; Gow, 2002)cap
Assimilatory modification is acoustically continuous.
Assimilation as Continuous Detail
F2 Transitions in /æC/ Contexts
Pitch Period155016001650
1700175018001850
Freq
uenc
y (H
z)
F3 Transitions in /æC/ Contexts
Pitch Period2550
2600
2650
2700
2750
2800
Freq
uenc
y (H
z)
coronalassimilatedlabial
Assimilation blends cues to two places of articulation
An Alternative View
Assimilation redistributes and blends information
cat box [# ]
Labiality of assimilatingitem
Coronality of assimilateditem
In theory: assimilation creates correlated cues…
[ # ]
Assimilating context might disambiguate blend
Blend might facilitate recognition of context
How can we determine if listeners use this information during recognition?
These questions require a method that:
• Measures lexical activation.• Sensitive to continuous acoustic detail.• Sensitive to temporal uptake of information.• Measures consideration of multiple items in parallel.
Visual World Paradigm
Visual World Paradigm
•Subjects hear spoken language and manipulate objects in a visual world.
•Visual world includes set of objects whose names represent competing hypotheses for the input.
•Eye-movements to each object are monitored throughout the task.