Seminar: Christopher Summerfield
Date: December 04, 2015. 10:00
Location: Seminar Room
Title: Adaptive gain control during perceptual decision-making in monkeys and humans.
Affiliation: University of Oxford, UK.
Optimal models suggest that perceptual choices occur following linear summation of noisy inputs to a threshold level. However, how prior knowledge (expectations) influence perceptual decisions remains controversial. I will describe a series of studies in which humans integrate visual feature information from multiple discrete sources. These experiments suggest that expected information is processed with higher gain, leading to suboptimal biases, including a tendency to confirm favoured hypotheses, and a bias to discount or downweight outlying information. I will present a computational model that explains these findings, and suggests that overweighting expected information is a result of an adaptive gain control process that allows efficient allocation of limited resources in decision space. Finally, I will describe single-cell data recorded from area IT whilst macaques made perceptual decisions about noisy visual percepts that were expected or unexpected.