Oxyopia Abstract

April 2, 2009
Friday, 4:00 PM
489 Minor Hall

Wilson S. Geisler, PhD
David Wechsler Regents Professor of Psychology, Center for Perceptual Systems and Department of Psychology, University of Texas at Austin
Host: TBA

  Russell De Valois Memorial Lecture [info]

Title

Natural Systems Analysis of Visual Search

Abstract

The environments in which an organism lives and the tasks it performs within those environments shape its perceptual and motor systems through evolution and experience. This is an obvious statement, but it implies several fundamental components of research that are needed to gain a deep understanding of perceptual and motor systems. The first is to identify the natural tasks performed by the organism under natural conditions. The second is to measure and analyze those environmental properties (natural scene statistics) and biological properties (fundamental sensory and motor constraints) relevant for performing the tasks. The third is a mathematical analysis to determine how a rational (ideal) perceptual system would exploit the measured environmental and biological properties to perform the tasks. This component is critical because it provides insight into the information contained in the natural stimuli and it can suggest principled hypotheses for the neural mechanisms the organism might use to exploit that information. The fourth component is to formulate specific hypotheses for neural mechanisms, based on the first three components, and test them in physiological and behavioral studies that capture the essence of the natural task. This general approach is illustrated with studies of visual search that combine measures of natural scene statistics, measures of relevant properties of retinal encoding, derivation of ideal Bayesian observers that exploit those statistical and retinal properties, and behavior experiments that compare human and ideal speed, accuracy and eye movements during visual search. These studies and other recent studies demonstrate the great potential of "natural systems analysis" for producing advances in behavioral science and systems neuroscience.

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