title: Effects of attention on motion repulsion.
abstract: Motion repulsion involves interaction between two directions of motion. Since attention is known to bias interactions among different stimuli, we investigated the effect of attentional tasks on motion repulsion. We used two overlapping sets of random dots moving in different directions. When subjects had to detect a small speed-change or luminance change for dots along one direction, the repulsive influence from the other direction was significantly reduced compared with the control case without attentional tasks. However, when the speed-change could occur to either direction such that subjects had to attend both directions to detect the change, motion repulsion was not different from the control. A further experiment showed that decreasing the difficulty of the attentional task resulted in the disappearance of the attentional effect in the case of attention to one direction. Finally, over a wide range of contrasts for the unattended direction, attention reduced repulsion measured with the attended direction. These results are consistent with the physiological finding that strong attention to one direction of motion reduces inhibitory effects from the other direction.
authors.affiliation: Center for Neurobiology and Behavior, Department of Physiology and Cellular Biophysics, P.I. Annex Rm 519, Columbia University, 1051 Riverside Drive, New York, NY 10032, USA.
authors.forename: Yuzhi
authors.initials: Y
authors.lastname: Chen
authors.forename: Xin
authors.initials: X
authors.lastname: Meng
authors.forename: Nestor
authors.initials: N
authors.lastname: Matthews
authors.forename: Ning
authors.initials: N
authors.lastname: Qian
mesh_terms: D001288:Attention; D015350:Contrast Sensitivity; D003463:Cues; D006801:Humans; D008029:Lighting; D009039:Motion Perception; D010775:Photic Stimulation / Q000379:methods; D011601:Psychophysics