[An inducing mechanism of the Craik-O'Brien and the Cornsweet effects (author's transl)].

The effect of edges on apparent lightness of the uniform luminous field was investigated in the so-called Craik-O'Brien and Cornsweet patterns as compared with that in the edgeless uniform field. It was found that white edge in the Craik-O'Brien pattern of Type II as well as a black edge in that of Type I lowered or darkened apparent lightness of the field on both side of the edge. The so-called Craik-O'Brien effect was due to assymmetry of the edge-effect on the two sides. The darkening effect of the white edge was explained by the antagonistic lateral inhibition. The same effect of the black edge was explained by a newly introduced concept of non-antagonistic inhibition. The Cornsweet effect was a combination of two edges, white and black, but not simply a summation but a complicated interaction of them.