Psycholphysical 'measurement' of cortical colour mechanisms: reply of Meyer

In a paper recently published in this journal, Meyer criticised our study on relationships between channels for colour and spatial frequence for not being able to demonstrate a size aftereffect not specific to colour, a McCollough effect not specific to size, or the functions of cortical colour mechanisms. In fact, our study attempted none of these demonstrations in the sense suggested by Meyer because the first would have been impossible for empirical reasons, the second for conceptual reasons, and the third for methodological reasons. Instead, our study yielded evidence that at least three different types of perceptual channel underlie our capacity to perceive the size and colour of objects.