The phantom array: A perisaccadic illusion of visual direction

Abstract

Naive observers (N = 75) were asked to saccade in the dark across a point light source blinking on and off at 200 Hz and to describe the resultant phantom array (Hershberger, 1987). The vast majority represented this per saccadic illusion of visual direction essentially as Hershberger described it Replicable features of the phantom array imply that the perisaccadic shift of retinal local signs (i.e., spatiotopic coordinates) is discontinuous, comprising two separate parts, a discrete partial shift that occurs before the eyes start to move, and a continuous partial shift that is completed at about the same time as the eye movement. Although these implications are consistent with recent experimental findings, they are inconsistent with the received view that retinal local signs shift sluggishly. The phantom array implies that the faster, presaccadic, partial shift has a time constant of 5 ms or less.