Interaction between horizontal and vertical fusional responses

Abstract

Human fusional responses to combinations of horizontal and vertical disparity presentations were studied in order to determine how the horizontal and vertical fusional components are utilized during the response. Vertical fusional amplitudes decreased in the presence of large horizontal disparities. The reaction time to a vertical-step disparity increased when a horizontalstep disparity was simultaneously presented. Neither horizontal fusional amplitudes nor horizontal vergence responses to step or ramp disparity presentations were affected by the presence of vertical disparities. Thus, the results indicate a unilateral interaction between horizontal and vertical fusional components, one in which the fusibility of a compound disparity is affected by the order in which the disparity components are introduced. © 1983 Psychonomic Society, Inc.