Close binding of identity and location in visual feature perception.

Abstract

The binding of identity and location information in disjunctive feature search was studied. Ss searched a heterogeneous display for a color or a form target, and reported both target identity and location. To avoid better than chance guessing of target identity (by choosing the target less likely to have been seen), the difficulty of the two targets was equalized adaptively; a mathematical model was used to quantify residual effects. A spatial layout was used that minimized postperceptual errors in reporting location. Results showed strong binding of identity and location perception. After correction for guessing, no perception of identity without location was found. A weak trend was found for accurate perception of target location without identity. We propose that activated features generate attention-calling "interrupt" signals, specifying only location; attention then retrieves the properties at that location. Many important tasks require people to determine object identities and their locations, what Sagi and Julesz (1985) have called the "what" and "where" of visual perception. What we do with information about the identity of an object depends upon where it is located. Not only do oven responses to objects need to be directed to the appropriate location, but also further perceptual analysis of objects typically requires controlling the direction of eye movements or the locus of spatial attention. Achieving proper binding of identity perception