You say “tomato”, I say “tumatu”. The influence of prior expectations on perception in social interaction

Our ability to successfully interact with other people depends on recognizing and understanding other persons in different contexts. Especially, when sensory signals are degraded, informative priors can improve perception but may also lead to deception. Therefore, unravelling how the human brain combines sensory input from face and voice with prior knowledge is important. In my talk, I will present data from several studies investigating how prior expectations influence perception in social interaction. Firstly, I will contrast two functionally distinct computational mechanisms by which prior expectations can influence sensory representations of speech. Expected features of the input can be enhanced or sharpened. Alternatively, in Prediction Error accounts, expected features are suppressed and unexpected signals are processed further. We aimed at distinguishing between these two accounts by combining behavioural, univariate, and multivariate fMRI measures with computational models. Secondly, I will address the question why we are better in understanding familiar speakers with data from behavioural online studies, in which listeners could use voice context to normalize vowel perception. Finally, I will discuss how the human brain could represent the strength of prior expectations during face-identity recognition.