Citation

Bacon WF, Egeth HE. J. Exp. Psychol. Hum. Percept. Perform. 1991; 17(1): 77-90.

Affiliation

Department of Psychology, Johns Hopkins University, Baltimore, Maryland 21218.

Copyright

(Copyright © 1991, American Psychological Association)

DOI

unavailable

PMID

1826324

Abstract

Sagi and Julesz (1987) claimed that for a target to be detected preattentively, it must be within some small critical distance of a nontarget. The independent effects of separation and display size, which were confounded in the Sagi and Julesz experiments, were examined. Experiments 1 and 2 revealed that in tasks requiring search for a color-defined target, target-nontarget separation had no effect on reaction time (RT). Display size, however, was inversely related to RT. Experiment 3 ruled out the possibility that the decreasing function of RT with display size was due to arousal caused by higher display luminance. When nontarget grouping was inhibited, (Exp. 4) it was found that RT no longer decreased with increasing display size. This suggests that nontarget grouping may have been the cause of the improved performance at larger display sizes. Experiments 5 and 6 extended the results to line segments, the stimuli used by Sagi and Julesz.

Language: en