Corner effect in induced hue: evidence for chromatic band-pass filters

An experiment is described which investigates the spatial determinants of the apparent difference in hue between the central grey patches of chromatic 'H' pattern pairs, an effect similar to that first demonstrated by Wright (1969, The Measurement of Colour, Hilger, London) in coloured gratings. The hue difference is shown to be analogous to the brightness difference in achromatic 'H' patterns demonstrated by Moulden and Kingdom (1989, Vision Res. 29, 1245-1259). The origin of both effects is argued to be the presence of the corner intersections in the 'H' patterns, which are powerful stimuli for cells with circularly-symmetric, centre-surround organization. It is suggested that the results of the experiment with the chromatic 'H' patterns implicates the operation of cells with a spectrally double-opponent, rather than single-opponent receptive field organization.