Task-dependent effects of social attention on saccadic reaction times.
Previous research has shown that saccadic reaction times (SRTs) are shorter when a stimulus is flashed on the same side as the observed gaze direction of another individual. The gaze imitation hypothesis contends that observed gaze evokes the preparation of a saccade toward the same direction. Previous studies of this phenomenon have employed pro-saccade tasks in which the instructed saccade is directed toward the stimulus. In agreement with previous findings, we found that SRTs on pro-saccade trials were shorter when the stimulus appeared in the same direction as observed gaze. Here we also included anti-saccade trials in which subjects were required to look-away from a stimulus and toward its mirror position in the opposite visual field. The gaze imitation hypothesis predicts that subjects will have shorter SRTs on anti-saccade trials in which the stimulus appears opposite the observed gaze direction because they will have prepared already a saccade in that direction. However, contrary to the prediction of the gaze imitation hypothesis, we found that subjects had shorter SRTs on anti-saccade trials when the stimulus appeared in the same direction as observed gaze. Moreover, subjects also made more pro-saccade errors on anti-saccade trials in which the stimulus was presented opposite the observed gaze direction. The results of our study indicate that subjects prepared a saccade in the same direction as observed gaze on pro-saccade trials but opposite the observed gaze direction on anti-saccade trials. These findings suggest that the effect of social gaze cues on SRTs is task dependent.
Koval
Michael J
MJ
Graduate Program in Neuroscience, University of Western Ontario, London, ON, N6G 2V4, Canada.
Thomas
Benson S
BS
Everling
Stefan
S
D000328:Adult; D001288:Attention / Q000502:physiology*; D003627:Data Interpretation, Statistical; D004585:Electrooculography; D004594:Electrophysiology; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*; D012018:Reflex / Q000502:physiology; D012438:Saccades / Q000502:physiology*; D012931:Social Environment