Dale Purves

Work in the Purves laboratory is concerned with visual perception and its neurobiological underpinnings. Ongoing investigations include understanding the perception of brightness, color, orientation, motion, and stereoscopic depth. The unifying theme of these several objects is the hypothesis that visual precepts are generated according to a wholly empirical strategy that represents to the observer the empirical significance of the stimulus rather than its properties as such. The neural basis of this strategy is taken to be the weighting of synaptic connections in a neural network, driven by feedback from the success or failure of visually guided behavior. In this conception, experience in both ontogeny and phylogeny promotes the formation of activity-dependent associative neural circuitry that instantiates the probability distribution of the possible causes of a given stimulus. What we see is therefore a reflex result of the neuronal set triggered by the stimulus. The validity of this theory of vision is also being explored by examining the properties of virtual organisms that evolve in defined visual environments.