Philosophy, Psychology and Neuroscience

Colour perception without awareness

The visual system might exploit variations in the wavelength of light for a number of purposes. We most often think of wavelength as something that allows us to attribute particular colours to objects. Boundaries between regions of a scene with different wavelength composition might also contribute to the process of segmenting objects from their backgrounds independently from the perception of object colour. I will question whether either of these aspects of wavelength processing are necessarily associated with having an experience of colour. I will review work on the neurological condition of cerebral achromatopsia with respect to border processing and the perception of form from colour (e.g. Kentridge et al., 2004, Neuropsychologia 42 821–30) and more recent work on colour constancy and masking with respect to the perception of surface colour (Norman et al., 2014, Current Biology 24 2822–6).