An empirical explanation of the Chubb illusion

The perceived difference in brightness between elements of a patterned targ et is diminished when the target is embedded in a similar surround of highe r luminance contrast (the Chubb illusion). Here we show that this puzzling effect can be explained by the degree to which imperfect transmittance is l ikely to have affected the light that reaches the eye. These observations i ndicate that this 'illusion' is yet another signature of the fundamentally empirical strategy of visual perception, in this case generated by the typi cal influence of transmittance on inherently ambiguous stimuli.