cue reliability and re-weighting in word...
TRANSCRIPT
Cue Reliability and Re-Weighting in Word Recognition
Goals of Study
General Approach
Conclusions
Listeners are influenced by the distributions of cues in the current input Listeners can dynamically re-weight cues in response Listeners selectively re-weight cues (i.e., don’t converge to 50/50 responses) Important for future cue integration experiments: most standard balanced designs create conflict
References & Acknowledgments
[1] Connine, Blasko & Hall (1991) JML; [2] Szostak & Pitt (2013) APP; [3] Bicknell et al (in revision) [4] Idemaru & Holt (2011) JEP:HPP This work was partially funded by NSF NRT #1449828 (W.B.) and NICHD R01 HD075797 (T.F.J.).
Manipulate acoustic cues (VOT) and semantic cues (biasing context) in a sentence (see [1,2,3]) Task: did you hear “tent” or “dent”? Mechanical Turk subjects (N = 106) VOTs: 10, 30, 35, 40, 50, 85ms 7 sentence frames repeated for each semantics, distance, & VOT combination = 168 total trials (no fillers)
1Department of Brain & Cognitive Sciences, University of Rochester 2Department of Computer Science, University of Rochester
Wednesday Bushong1 and T. Florian Jaeger1,2
dent-biasing/tent-biasing semantic context
/d/-like VOT /t/-like
Results
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20 40 60 80Voice Onset Time (ms)
Pro
port
ion
Res
pons
es /t
/ Semantic CueDent-biasingTent-biasing
Responses by Cue Conditions
Semantic & acoustic cues are integrated: categorization responses in both groups (collapsed in graph) are sensitive to both VOT and biasing context.
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10 30 35 40 50 85VOT (ms)
Sem
antic
Cue
Effe
ct (
log-
odds
)
GroupHigh-ConflictLow-Conflict
Semantic Cue Effect by Group
High-Conflict group down-weights effect of semantic cue on their responses over course of experiment while Low-Conflict stays constant
Changes in Cue Weights Over Time
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-1 0 1Trial (Scaled)
Pre
dict
ed s
eman
tic e
ffect
(log-odds)
GroupHigh-ConflictLow-Conflict
Semantic Cue(a)
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-1 0 1Trial (Scaled)
VO
T (m
s)
-1
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GroupDifference(log-odds)
Acoustic Cue(b)
Little change in weighting of VOT over time in either group
High-Conflict Group Low-Conflict Group
10 30 35 40 50 85 10 30 35 40 50 850
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<- More /d/-like More /t/ like -> <- More /d/-like More /t/-like ->
Voice Onset Time (ms)
Num
ber o
f Tria
ls
Semantic Cue Dent-biasing Tent-biasing
Distribution of Cues by Exposure Group
...the ?ent in the fender/forest...
High-Conflict group shows a smaller effect of semantic cue on responses
Beginning Middle End
20 40 60 80 20 40 60 80 20 40 60 80
-5.0
-2.5
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VOT
Est
ima
ted
/t/ r
esp
on
se
(log-odds)
GroupHigh-ConflictLow-Conflict
Listeners integrate top-down and bottom-up cues in speech perception But cues are distributed differently in different contexts (e.g., between speakers) Do listeners adaptively change cue weightings given new exposure distributions?
Why Do We See This Re-Weighting
Pattern? Listeners could reduce cue conflict by downweighting either VOT or semantics. Why do listeners downweight semantics? Use of multiple acoustic cues can show similar effects: when correlations between two acoustic cues are perturbed, listeners down-weight the less reliable cue [4] This could suggest that listeners might consider semantic information to be less reliable than acoustic features (at least in word recognition tasks)
Manipulation
High-Conflict Group: VOT & semantic cues perfectly uncorrelated (i.e., very /d/-like stimuli paired with tent-biasing semantics as much as dent-biasing semantics) Low-Conflict Group: VOT & semantic cues are correlated in the expected direction
How can we measure relative reliability of semantic & acoustic features to word recognition? Do listeners rationally re-weight cues given evidence over time?
Future Work
Smaller semantic effect strikingly consistent across subjects
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0.0 2.5 5.0Empirical semantic effect (log-odds)
# S
ubje
cts
GroupHigh-ConflictLow-Conflict