Colloquium: Mary A. Peterson

    Date: 
    Thursday, October 25, 2012 - 3:30pm - 5:00pm
    Location: 
    Meinel 307
    Description: 

    Mary A. Peterson from the University of Arizona will present "Memory Influences on Figure-Ground Perception: Evidence for Reentrant Processing."

    Abstract(s): 

    The Gestaltists and many followers held that figure-ground segregation occurs early in the course of processing before memories of object structure or category membership are accessed and that later, such memories are accessed for figures but not for grounds. Thus, figure-ground perception was explained within a serial hierarchical architecture in which information flows in a feedforward manner only and figural status gates what type of processing occurs for display regions. Many modern theorists continue to hold the position that perception can be accomplished via a feedforward processes alone, although they rarely discuss figure-ground perception. Yet figure-ground perception can inform debates regarding whether feedforward mechanisms alone can account for visual perception. Using brain imaging techniques (ERPs) and behavioral tests, my colleagues and I have conducted experiments showing that figure-ground perception takes place in a system that includes reentrant (feedback) connections. In this dynamical system properties of objects that might be perceived on opposite sides of borders are assessed in a fast pass of processing that reaches high levels. Object properties on opposite sides of borders compete for representation; the winner is perceived as the shaped figure and the response to the loser is suppressed. In attempting to characterize the entire dynamical system involved in figure-ground perception, we recently found that suppression of the alternative that loses the competition for figural status is relayed to lower but not higher processing levels.

    Speaker Bio(s): 

    Mary A. Peterson is a professor in the University of Arizona Department of Psychology, where she also serves as professor and director of the Cognitive Science Program. She also serves as chair of the Cognitive Science Graduate Interdisciplinary Program.