The influence of retinal image motion on the perceptual grouping of temporally asynchronous stimuli

Abstract

Briefly presented stimuli can reveal the lower limit of retinal-based perceptual stabilization mechanisms. This is demonstrated in perceptual grouping of temporally asynchronous stimuli, in which alternate row or column elements of a regular grid are presented over two successive display frames with an imperceptible temporal offset. The grouping phenomenon results from a subtle shift between alternate grid elements due to incomplete compensation of small, fixational eye movements occurring between the two presentation frames. This suggests that larger retinal shifts should amplify the introduced shifts between alternate grid elements and improve grouping performance. However, large shifts are necessarily absent in small eye movements. Furthermore, shifts follow a random walk, making the relationship between shift magnitude and performance difficult to explore systematically. Here, we established a systematic relationship between retinal image motion and perceptual grouping by presenting alternate grid elements (untracked) during smooth pursuit of known velocities. Our results show grouping performance to improve in direct proportion to pursuit velocity. Any potential compensation by extraretinal signals (e.g., efference copy) does not seem to occur.

Microsaccadic Eye Movements but not Pupillary Dilation Response Characterizes the Crossmodal Freezing Effect

“…2019 ). In our case, attention on auditory events could serve as a temporal trigger, shift the balance of oculomotor (spontaneous) maps, and favor or even consolidate the nonretinotopic channel, which binds the audiovisual events and produces the dominant percept of “group motion” ( Park et al. 2019 ).…”

“…Microsaccades, as 1 type of fixational eye movement, can preserve vision by preventing perceptual fading ( Zuber and Stark 1966 ; Beeler 1967 ; Engbert and Mergenthaler 2006 ; Martinez-Conde et al. 2006 , 2009 , 2013 ; Hafed and Krauzlis 2010 , 2012 ; Hafed and Ignashchenkova 2013 ; Park et al. 2019 ).…”