Inhomogeneous surrounds, conflicting frameworks, and the double-anchoring theory of lightness.
The empirical question of whether or not the lightness of a region is accounted for purely by the average luminance of its surround has a complex answer that depends on whether such a region is an increment, a decrement, or intermediate relative to the luminances of the contiguous surfaces. It is shown here that a new model of lightness, based on anchoring principles, predicts and clarifies such intricacies. In this model, the luminance of the target region determines its lightness in two ways: indirectly, by causing it to group with parts of its surround and thus defining the nested frameworks to which it belongs; and directly, by anchoring it to the highest luminance and to the average surround luminance in each of these frameworks. Inter- and intraindividual differences in lightness assessment are shown to emerge under grouping conditions that create unstable, conflicting frameworks.
Bressan
Paola
P
Dipartimento di Psicologia Generale, Università di Padova, Via Venezia 8, 35131 Padova, Italy. paola.bressan@unipd.it
D001288:Attention; D003220:Conflict, Psychological; D015350:Contrast Sensitivity; D005364:Field Dependence-Independence; D006801:Humans; D007206:Individuality; D049449:Luminescence; D011582:Psychological Theory; D011601:Psychophysics