THE CRAIK-O'BRIEN-CORNSWEET EFFECT AND BRIGHTNESS INDUCTION BOTH PROCEED BY THE SPREADING OF BRIGHTNESS INFORMATION

T. Maddess, M. V. Srinivasan, M. P. Davey and A. C. James

Background: The Craik-O'Brien Cornsweet effect (COCE) is a visual illusion where the luminance of image boundaries sets the apparent brightness of enclosed regions. The COCE may be produced by the cortex constructing the observed brightness through a lateral 'filling-in' process: propagating brightness information from the edges of the enclosed regions towards their centres. Any such filling-in process would imply a speed of propagation.

Methods: Data on the propagation speed of brightness information in two different brightness induction effects are compared using a multivariate regression analysis.

Results/Conclusion: We demonstrate similar non-zero speeds for the COCE and for a brightness contrast effect.