Under a recent sensorimotor theory of vision (O'Regan and Noë,
2001 Behavioral and Brain Sciences, in press),
no detailed internal representation of visual scenes need be stored in
the brain. All that need be stored is recipes that allow an observer to
check that attended objects are actually present. The phenomenon of change
blindness was predicted by this view.
Another prediction of the sensorimotor theory concerns the sensation of colour. Because of the drop-off in cone density with eccentricity, and because of differences in optical absorption, colours are sampled differently in peripheral than in central vision. As a result, when the eye moves, certain predictable eye-movement-contingent changes occur in sensory input. Under the sensorimotor theory, we have the sensation of colour when we know that these particular contingencies are currently applicable.
To test this idea we carried out an experiment where, using eye-movement monitoring, we systematically changed the normal contingencies that define colour. In a habituation phase, observers looked, for example, at a red patch on a computer display. Whenever they moved their eyes off the patch, it tinged with blue. We report the extent to which observers' matches of red in central and peripheral vision are modified by this manipulation.
© 2001 Pion Ltd