Quickly fading afterimages: hierarchical adaptations in human perception

TL;DR

This study reveals that human afterimages can be rapidly erased within a second when viewing rich visual content, and this skill improves with practice, supporting a hierarchical adaptive mechanism in perception.

Contribution

It demonstrates rapid, learned erasure of afterimages linked to hierarchical adaptive processes in human visual perception.

Findings

Approximately 50% of afterimage intensity can be erased quickly.

Rich visual content facilitates faster afterimage removal.

Practice enhances the ability to erase afterimages.

Abstract

Afterimages result from a prolonged exposure to still visual stimuli. They are best detectable when viewed against uniform backgrounds and can persist for multiple seconds. Consequently, the dynamics of afterimages appears to be slow by their very nature. To the contrary, we report here that about 50% of an afterimage intensity can be erased rapidly--within less than a second. The prerequisite is that subjects view a rich visual content to erase the afterimage; fast erasure of afterimages does not occur if subjects view a blank screen. Moreover, we find evidence that fast removal of afterimages is a skill learned with practice as our subjects were always more effective in cleaning up afterimages in later parts of the experiment. These results can be explained by a tri-level hierarchy of adaptive mechanisms, as has been proposed by the theory of practopoiesis.