ABSTRACT
In an influential article that appeared in Science in 1969, Schneider1 postulated an anatomical separation between the visual coding of the location of a stimulus and the identification of that stimulus. He attributed the coding of the location to the ancient retinotectal pathway, and the identification of the stimulus to the newer geniculostriate system; this distinction represented a significant departure from earlier monolithic descriptions of visual function, However, the notion of 'localization' failed to distinguish between the many different patterns of behaviour that vary with the spatial location of visual stimuli, only some of which turn out to relv on tectal mechanisms2--4• Nevertheless, even though Schneider's original proposal is no longer generally accepted, his distinction between object identification and spatial localization, between 'what' and 'where', has persisted in visual neuroscience.
