The role of spatial articulation in Agostini & Galmonte reversed lightness induction Necker cube.

gostini and Galmonte (2002 Psychological Science 13 88 - 92) offered a display in which a gray surrounded by black is perceived as darker than an identical gray surrounded by white because of global induction effects elicited by grouping factors, showing that, at least under certain conditions, higher-level factors prevail on lower-level factors, ie the lightness induction produced by the global organization principle of perceptual belongingness prevails on retinal lateral inhibition. The present study was aimed to test whether the lightness induction produced by perceptual grouping does depend on the configuration spatial articulation. In order to test this hypothesis we systematically manipulated the spatial articulation, starting from the original Agostini and Galmonte configuration and then gradually decreasing its complexity. Observers had to perform a global judgment, matching the lightness of the induced elements on a Munsell scale. We found that the lightness induction produced by belongingness is modulated by the spatial articulation level. Results are interpreted in the light of previous studies on the relationship between lightness induction and spatial articulation