The challenge of measuring long-term positive aftereffects

Abstract

Summary Adaptation is one of the longest-studied phenomena in perception and neuroscience. Adaptation generally results in negative perceptual aftereffects: after prolonged exposure to a specific feature, perception of a neutral stimulus is biased in the opposite direction [1,2]. A recent paper in Current Biology [3] challenged this view by proposing that, additionally, adaptation biases perception in the same direction as features observed over a relatively long time from the past. This finding challenges dominant theories of visual adaptation; however, here we argue that long-term positive correlations are not due to neural or perceptual processes but arise due to short-term negative aftereffects. Thus, existing models of adaptation remain unchallenged, and critical evaluations of how adaptation could predictively aid perception are still needed.