28 Feb 2014
Dale Purves
Centre for Cognitive Neuroscience
Duke University
Biological visual systems cannot measure the properties that define the physical world. Nonetheless, visually guided behaviors of humans and other animals are routinely successful. The purpose of this talk will be to consider how this feat is accomplished. Most concepts of vision propose, explicitly or implicitly, that visual behavior depends on recovering the sources of stimulus features either directly or by a process of statistical inference. I will argue that, given the inability of the visual system to access the properties of the world, these conceptual frameworks cannot account for the behavioral success of biological vision. The alternative I present is that the visual system links the frequency of occurrence of biologically determined stimuli to useful perceptual and behavioral responses without ever recovering real world properties. The evidence for this interpretation of vision is that the frequency of occurrence of stimulus patterns predicts many aspects of what we actually see. This strategy provides a different way of conceiving the relationship between objective and subjective experience, and offers a way to understand the operating principles of visual circuitry without invoking feature detection, representation, or probabilistic inference.