Citation

Kingstone A, Klein RM. J. Exp. Psychol. Hum. Percept. Perform. 1993; 19(6): 1251-1265.

Affiliation

Center for Neuroscience, University of California, Davis 95616-8768.

Copyright

(Copyright © 1993, American Psychological Association)

DOI

unavailable

PMID

8294890

Abstract

Saccadic reaction time (RT) is reduced when a fixation stimulus is extinguished 200 ms before a target appears. An attentional predisengagement theory (APT) may explain this gap effect: When covert attention is engaged (e.g., on fixation), the saccadic system is inhibited and RT is delayed; when the attended stimulus is extinguished, attention is disengaged, the inhibition is removed, and RT is facilitated. In 3 experiments covert attention was endogenously or exogenously cued to an object on the vertical meridian. Onset of a saccadic target on the horizontal meridian could be preceded by the offset of an attended or unattended object. Contrary to APT, RTs were identical after attended and unattended offsets. Results suggest that the gap effect has 2 components, and covert visual attention plays no role. One component is motor system preparation; the other is a fixation offset effect specific to the oculomotor system.

Language: en