Object identity determines trans-saccadic integration

Abstract

Humans make two to four rapid eye movements (saccades) per second, which, surprisingly, does not lead to abrupt changes in vision. To the contrary, we perceive a stable world. Hence, an important question is how information is integrated across saccades. To investigate this question, we used the sequential metacontrast paradigm (SQM), where two expanding streams of lines are presented. When one line is spatially offset, the other lines are perceived as being offset, too. When more lines are offset, all offsets integrate mandatorily; that is, observers cannot report the individual offsets but perceive one integrated offset. Here, we asked observers to make a saccade during the SQM. Even though the saccades caused a highly disrupted motion trajectory on the retina, offsets presented before and after the saccade integrated mandatorily. When observers made no saccade and the streams were displaced on the screen so that a similarly disrupted retinal image occurred as in the previous condition, no integration occurred. We suggest that trans-saccadic integration and perception are determined by object identity in spatiotopic coordinates and not by the retinal image.

Perceptual History Acts in World-Centred Coordinates

“…Another is that our paradigm specifically puts the two effects in conflict: When in conflict, allocentric effects may dominate. This would agree with recent results looking at allocentric motion perception ( Drissi-Daoudi et al., 2020 ).…”

Perceptual history acts in world-centred coordinates

“…One of the reasons for the difference may be that here we put retinotopic and allocentric signals in conflict, so the stronger one dominates. There may exist retinotopic effects, but these would seem to be overridden by more robust spatiotopic effects when one is pitted against the other, agreeing with a recent study on allocentric motion perception (Drissi-Daoudi et al, 2020).…”

Effects of Transient Loss of Vision on Head and Eye Movements during Visual Search in a Virtual Environment

“…Furthermore, it is worth noting that the addition of eye and head movements placed most saccade landing positions just outside of the mask (at the time of saccade planning). If replicated, this would stand in contradiction with theories of trans-saccadic memory requiring an object to target in the periphery [86,87]. On another hand, it seems that deviating from saccadic landing points does not necessarily impact trans-saccadic integration, because attention is not necessarily located at the saccadic landing point [88][89][90].…”