Proceedings of the Annual Meeting of the Cognitive Science Society

Individuals implicitly learn the statistics of environmental stimuli. We used ”contraction bias”, the tendency toperceive stimuli closer to the estimated mean of similar previous stimuli, to characterize the dynamics of these implicit inferenceprocesses. Using a simple auditory discrimination task we found that listeners build a rich representation of the distribution ofpast stimuli, and yet over represent very recent events. This combined pattern allows both learning of the stable environment,and flexibility to fast changes.We further characterized populations who have difficulties in acquiring specific expertise, i.e. specific developmental dis-orders, focusing on reading (dyslexia) and non-verbal communication (high functioning ASD, autism spectrum, individuals)disability, respectively. We found that the pattern of their perceptual inference differs from controls’. Both underweight pre-vious events. However, dyslexics’ implicit memory decays fast and they underweight earlier events, whereas ASD individualsunderweight recent events. This pattern parallels, and perhaps underlies, their strengths and weaknesses.