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Abstract

Sensorimotor theories of perception argue that action plays a constitutive role in all perception, even in cases such as colour vision, where action is not usually considered to be required. According to these approaches, colour could be defined by the specific transformations induced in cone excitation by eye movements. Replicating an old, controversial experiment of Kohler, we used left-field blue/right-field yellow spectacles to introduce an artificial regularity between eye movements and colour changes. Focusing on short-term effects and dynamic aspects of the exposure and test stages, we obtained measurable adaptation in colour judgment in 40 min. This perceptual learning resulted in the dependence of colour judgment on the direction of eye movements, in a way that compensated for the sensorimotor regularity introduced by the spectacles. A second computer-controlled experiment confirmed these results for luminance judgment after 20 min of exposure. Our experiments established clearly the necessity of eye movement for perceptual learning and argue for a role of action in colour vision.