p165fig04.41 The Kanizsa-Minguzzi ring.  See the text for details.<BR>|| p165c1h0.6 "... (left panel), the annulus is divided by two line segments into annular sectors of unequal area. Careful viewing shows that the smaller sector looks a little brighter than the larger one. (Kanizsa, Minguzzi 1986) noted that "this unexpected effect is not easily explained. In fact, it cannot be accounted for by any simple psychological mechanism such as lateral inhibition or freuency filtering. Furthermore, it does not seem obvious to invoke oganizational factors, like figural belongingness or figure-ground articulation."". p165c2h0.35 "... (Grossberg, Todorovic 1988). Our main claim is that the two radial lines play two roles, one in the formation of boundaries with which to contain the filling-in process, and the other as a source of feature contour signals that are filled-in within the annular regions to create a surface brightness percept. ..."