PSY 368 Lecture Notes - Lecture 11: Mach Bands, Edge Enhancement, Psy
9 Oct 2017
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Caused by differential lateral inhibition from cells on either sides of the band. Stim consists of dark-light/light-dark bars forming equal-sized and perfectly flat luminance steps. Mach bands ay serve to enhance perceptual edges: edge enhancement is a term referring to low-level accentuation of an edge to make an edge more easily used by a perceptual syst. More lateral inhibition means less firing cell b codes a dark mach band. Less lateral inhibition means more firing cell d codes light mach band. Surrounding a pattern with a lighter or darker region changes the perceived brightness of the surrounded pattern. Perhaps simultaneous lightness contrast is caused by lateral inhibition of the center pattern from the background: why does the entire square appear lighter or darker.
