Accession Number:

ADA273763

Title:

Search for Conjunctively Defined Target can be Selectively Limited to a Color-Defined Subset of Elements

Descriptive Note:

Final rept.,

Corporate Author:

INSTITUTE FOR PERCEPTION RVO-TNO SOESTERBERG (NETHERLANDS)

Report Date:

1993-08-30

Pagination or Media Count:

42.0

Abstract:

When searching for a conjunctively defined target, response latencies usually increase with the number of distractor elements, suggesting serial, self-terminating search through all display elements. However, Egeth, Virzi and Garbart 1984 showed that subjects do not necessarily search all display elements, but can limit their search to a color-defined subset of the elements. The present experiments tested Egeth et al.s conclusions using an improved paradigm. Subjects searched for a target defined as a conjunction of a color and an orientation. RTs for target present trials increased with the number of elements in that color and were independent of the number of elements in the other color, a finding which replicates Egeth et al.s results. Experiment 1 showed also that selective search of a color-defined subset did not depend on the saliency of the subset. Experiment 2 showed that selective search can be purely color-based and does not depend on luminance or brightness of the subset. Experiment 3 showed that subjects can flexibly change the subset they are searching for trial by trial. Implications of the present findings for current theories of visual search are discussed.

Subject Categories:

  • Nuclear Instrumentation
  • Fire Control and Bombing Systems
  • Optics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE