Feature integration is unaffected by saccade landing point, even when saccades land outside of the range of regular oculomotor variance

Abstract

The experience of our visual surroundings appears continuous, contradicting the erratic nature of visual processing due to saccades. A possible way the visual system can construct a continuous experience is by integrating presaccadic and postsaccadic visual input. However, saccades rarely land exactly at the intended location. Feature integration would therefore need to be robust against variations in saccade execution to facilitate visual continuity. In the current study, observers reported a feature (color) of the saccade target, which occasionally changed slightly during the saccade. In transsaccadic change-trials, observers reported a mixture of the pre- and postsaccadic color, indicating transsaccadic feature integration. Saccade landing distance was not a significant predictor of the reported color. Next, to investigate the influence of more extreme deviations of saccade landing point on color reports, we used a global effect paradigm in a second experiment. In global effect trials, a distractor appeared together with the saccade target, causing most saccades to land in between the saccade target and the distractor. Strikingly, even when saccades land further away (up to 4°) from the saccade target than one would expect under single target conditions, there was no effect of saccade landing point on the reported color. We reason that saccade landing point does not affect feature integration, due to dissociation between the intended saccade target and the actual saccade landing point. Transsaccadic feature integration seems to be a mechanism that is dependent on visual spatial attention, and, as a result, is robust against variance in saccade landing point.

Transsaccadic perception is affected by saccade landing point deviations after saccadic adaptation

“…As a second measure of integration, we therefore investigated whether the standard deviation was lower in the Color Constant condition than in the Post Only condition. Much like in a prior study using the same stimulus set-up ( Schut et al, 2018 ), we find inconclusive evidence for integration in terms of standard deviation reduction for both the adapted and unadapted] trials, BF 10 = 1.22 and BF10 = 1.59.…”

“…The experiment was conducted with the same apparatus/stimuli as Schut and colleagues (2018) . Observers supported their head with a chinrest at 70 cm distance from an Asus ROG Swift PG278Q monitor (60.1 × 34.0 cm, 2560 × 1440 pixels, 100 Hz; AsusTek Computer Inc., Taipei, Taiwan).…”

“…The fixation point was positioned 8° to the left or right from the vertical meridian of the screen approximately at eye-height. The target stimuli (colored circles) were 2° in diameter (a larger stimulus than our prior study, Schut et al, 2018 ), presented at an eccentricity of 16° from fixation. The larger target size was chosen to make the color more visible in the periphery.…”

“…In a recent study, we observed that the landing point of a saccade relative to a visual target does not influence the weights of the presaccadic and postsaccadic visual input, even in situations in which the saccade endpoint lands in between the target and a closely aligned distractor ( Schut, Van der Stoep, Fabius, & Van der Stigchel, 2018 ). Although there was extensive variance in the endpoint of the saccade across the two reported experiments, this variance did not influence transsaccadic feature integration.…”

Detection of object displacement during a saccade is prioritized by the oculomotor system

“…Because the visual system is retinotopically organized, the eye-movement system should be equipped with an updating mechanism that can adjust for retinal displacements produced by eye movements. The nature of such an updating mechanism is a matter of a longstanding debate with some researchers arguing for updating occurring slowly after each saccade (Golomb, Chun, & Mazer, 2008;Golomb & Kanwisher, 2012;Lescroart, Kanwisher, & Golomb, 2016;Mathôt & Theeuwes, 2010;Zimmermann, Morrone, Fink, & Burr, 2013) and others proposing that updating occurs rapidly, starting already before the start of a saccade (Arkesteijn, Belopolsky, Smeets, & Donk, 2019;He, Mo, & Fang, 2017;Melcher, 2007;Neupane, Guitton, & Pack, 2016;Rolfs, Jonikaitis, Deubel, & Cavanagh, 2011;Schut, Van der Stoep, Fabius, & Van der Stigchel, 2018, but see Arkesteijn et al, 2019).…”