Localisation of colour constancy; Investigation of the contribution of retinal and cortical processes in obtaining colour constancy

Abstract

There is still debate whether colour constancy is merely a result of retinal or cortical processes. In the current study, the contribution of both processes was investigated by comparing the performance of a group of colour-blind participants and controls on a colour constancy task in which object-colour associations from memory were taken along. Results show that cortical processes are most likely to be involved in obtaining colour constancy. The performance on colour constancy is comparable for both groups for natural physically coloured objects. When the colour of an object is removed, colour-blind participants, in contrast with normal observers, appear to make use of their memory (i.e. object-colour knowledge) to obtain colour constancy. Retinal input seems to be important for colour constancy to occur when there are no other visual cues available to make use of object-colour knowledge in the cortex. Furthermore, both groups showed more colour constancy for white objects with a diagnostic colour compared to non-diagnostic white objects. Apparently, those diagnostic objects are associated with a typical colour stored in memory which makes it easier to obtain colour constancy.