Stationary Objects Flashed Periodically Appear to Move During Smooth Pursuit Eye Movement

Abstract

We discovered that a white disc flashed twice at the same location appears to move during smooth pursuit eye tracking in the direction opposite to that of the eye movement. We called this novel phenomenon movement-induced apparent motion (MIAM). Using the method of constant stimuli, we measured the required displacement of the second appearance of the disc in the pursuit direction to null the effect during the closed-loop stage of smooth pursuit eye tracking. We observed a strong linear relationship between the points of subjective stationarity and the inter-stimuli intervals for four smooth pursuit eye movement speeds. The slopes and y-intercepts of these linear fits were well predicted by the hypothesis according to which subjects saw illusory motion from the first to the second retinal projections of the flashed disc during smooth pursuit eye movement, with no extra-retinal signal compensation.

A review of experimental task design in psychophysical eye tracking research

“…A dot flashed twice at the same position is perceived as moving in a direction opposite to the direction of a moving target during smooth pursuit eye movements, a process named movement-induction apparent motion (MIAM) ( Gosselin and Faghel-Soubeyrand, 2017 ). This process is similar to apparent motion (AM), in which two neighboring flashing lights are perceived as a unique light moving, during eye fixations.…”

“…This process is similar to apparent motion (AM), in which two neighboring flashing lights are perceived as a unique light moving, during eye fixations. Six adult participants participated in the task that demonstrated this effect ( Gosselin and Faghel-Soubeyrand, 2017 ). An EyeLink II system by SR Research sampling at 250 Hz was used for eye recordings, with participants at 66 cm using a chin rest to stabilize the head.…”