Chromatic masking revealed by the standing wave of invisibility illusion

We have used the standing wave of invisibility illusion (Macknik and Livingstone, 1998 Nature Neuroscience 1 144-149) to examine the masking effects produced by a range of stimuli of varying chromatic and luminance contrast content. The pattern of masking was highly selective. Maximum effects were always obtained when the target and mask were identical in terms of their chromatic and/or luminance contrast composition, but were reduced as the angular separation in colour space between them was increased. Masking was of a monopolar nature, indicating the operation of rectified mechanisms selective for different combinations of colour and luminance contrast.