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Causal inference in cue combination. Konrad Kording www.koerding.com. Modeling: Where do cues come from?. Generate. Traditional Bayesian model. Infer. Alais & Burr 04, Battaglia et al 03, Knill & Pouget 04, Ernst & Banks 02, Gahramani 95, van Beers et al, etc.
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Causal inference in cue combination Konrad Kording www.koerding.com
Modeling: Where do cues come from? Generate
Traditional Bayesian model Infer Alais & Burr 04, Battaglia et al 03, Knill & Pouget 04, Ernst & Banks 02, Gahramani 95, van Beers et al, etc
Visual Auditory combination (Ventriloquist effect) Both cues
Do we believe this kind of model? Assumes there is one and only one cause!
Alternative model or Kording, Beierholm, Ma, Quartz, Tenenbaum, Shams, 2007
Calculate probability of model • Using Bayes rule:
Independent causes: where is the auditory stimulus Audio Visual Best estimate
Common cause: where is the auditory stimulus Audio Visual Combined Best estimate
Mean squared error estimate Audio Visual Combine Best estimate Remark: Knill uses virtually identical math
Experimental test Button: common cause or two Wallace et al 2005 Hairston et al 2004
Measured gain Data Kording et al Sato et al, in press Wallace et al 2005 Hairston et al 2004
Predicting the variance Worse prediction if we assume model selection
Take home message • Uncertainty about causal structure • Bayesian framework is modular • Easy to extend • Causality problems occur in many domains
Acknowledgements • Ulrik Beierholm • Wei Ji Ma • Steven Quartz • Joshua Tenenbaum • Ladan Shams • Kunlin Wei