Expectations and visual aftereffects

Abstract

The tilt aftereffect (TAE) is traditionally regarded as a consequence of orientation-selective sensory adaptation, a low-level stimulus-driven process. Adaptation has been recently suggested to be the outcome of predictive coding. Here, we tested whether the TAE is modulated by predictability, and specifically, whether TAE depends on the congruency of adapted and expected orientations. Observers were presented with successive pairs of oriented Gabor patches. Pairs were arranged in blocks, forming two conditions with the orientation of the second pair member either predictable or not. For all pairs, the orientation of the first Gabor was tilted clockwise (CW) or counterclockwise (CCW) (±20° relative to vertical, randomized). In the "Expected" conditions, the orientation of the second Gabor was fixed relative to the first Gabor (the same or a mirror orientation, blocked). In the "no-expectation" condition, the orientation of the second Gabor was independent of the first Gabor (randomized ±20°). Intermixed test pairs were used to measure observers' perceived vertical, with the second pair member serving as a target, oriented around the vertical, permitting an estimate of the TAE produced by the presentation of the first Gabor. Results show an increase in TAE with the expected orientation matching the inducing orientation, but a decrease with the expected mirror orientation, consistent with additivity of the adaptation and the expectation effects. A second experiment, with the first oriented Gabor replaced by a colored circular blob, showed that expectation alone does not modulate the perceived orientation. These findings indicate a role for expectation in generating the perceptual TAE and are in line with predictive coding models of perception. We suggest that orientation dependent adaptation is affected by both the mean orientation (first order statistics) and by temporal contingencies (second order statistics).

Perceptual bias is reduced with longer reaction times during visual discrimination

“…6), with a large effect size (fixation: Cohen's d = 2.03, Hedges' g = 1.90, periphery: d = 1.85, g = 1.75, periphery non-retinotopic: d = 0.90, g = 0.85). The TAE fixation data from Pinchuk et al 16 replicated the effect ( Fig. 4d, statistics at Supplementary Table 1).…”

“…Sample size: Here, we use standard psychophysical methods employed in vision research. The effects studied (response bias, TAE and TI) are expected to be found with each observer tested in standard experimental conditions, as indicated by previous work (response bias 1 , TAE 6,16,48 , and the TI 49 ). The reader is invited to try (aftereffects 3,50 , TI 51,52 ).…”

“…In the laboratory experiments, N = 43 observers participated (32 females, 11 males, aged 26 ± 4, Mean ± SD, median of 25, in the range 18-40), including data from eleven observers obtained with permission from ref. 16 . One additional observer dropped out after the first session (for personal reasons), and her data were not analyzed.…”

“…Additional data. TAE fixation experiment from Pinchuk et al : We used, with permission, data from the "No expectation" and "Control" conditions reported in 16 , which used a nearly identical stimuli and procedure as the TAE fixation described above (N = 11 observers).…”

Interaction of contexts in context-dependent orientation estimation

“…Notably, there was no evidence for sub-additivity (as indicated by linearity for orientation repetition) and no evidence for selection (as indicated by linearity for orientation switch and side repetition). These findings are strengthened by a previous report on additivity of the TAE from adaptors and from learned expectations (Pinchuk-Yacobi, Dekel, et al, 2016). Further, Magnussen and Kurtenbach (1980) found additivity of 670 the TAE and the TI.…”