Experimental Psychology Seminar - How representations of prediction error explain speech perception and deception

Speaker: Helen Blank, Universitätsklinikum Hamburg-Eppendorf 

Perception depends on combining sensory input with prior knowledge. When sensory signals are degraded, informative priors can improve perception but may also lead to deception. In my talk, I will contrast two functionally-distinct computational mechanisms by which prior expectations can influence sensory representation of degraded speech. 

Expected features of the speech input can be enhanced or sharpened (Sharpened Signals). Alternatively, in Predictive Coding accounts, expected features are suppressed and unexpected signals (Prediction Errors) are processed further. I will present two fMRI experiments, which aimed at distinguishing between these two accounts. By combining behavioural, univariate and multivariate fMRI measures of how prior expectations lead to speech perception or speech deception, we provide evidence uniquely consistent with Prediction Error computations.