Figure 3.

Adaptation to Crowded Stimuli

(A) Observers either remained unadapted or adapted to either a single 45° Gabor at the target location, a noise patch crowded by 45° flankers, or the flankers in isolation (“crowded blank”). Following 5 s adaptation, a Gabor was presented at the target location for 200 ms at one of several possible orientations. Observers rotated a response Gabor (at fixation) to match their percept of the test.

(B) Changes in perceived orientation after adaptation, averaged across three observers. Negative values indicate clockwise rotations and positive values indicate counterclockwise rotations; error bars depict ±1 standard error of the mean. Adaptation to a single Gabor (green points) produced repulsion in perceived orientation that peaks at test orientations ±10°–15° from the adaptor. Adaptation to either crowded noise (red points) or crowded blanks (blue points) produces the same pattern at a lower magnitude, consistent with the presence of an oriented signal at the target location.