Adaptation Effects on the Apparent ‘Squareness’ of Square-Wave Gratings

Abstract

Adaptation to a 9 cycles deg⁻¹ sine wave makes the apparent brightness profile of a 3 cycles deg⁻¹ square wave look less ‘square’ even when it does not look like that of a sine wave. Adaptation to a 3 cycles deg⁻¹ sine wave has no noticeable effect. Hypotheses based on ‘excitation patterns’ across spatial-frequency-selective channels can account for these results; it is not clear whether variations in local light adaptation can also account for them.