Abstract

A number of researchers have reported that patterns have lower apparent contrast when surrounded by high-physical-contrast patterns with similar spatial frequency properties than when surrounded by lower-contrast patterns. This contrast contrast has been interpreted as revealing lateral interactions among neural gain signals. We report several cases where the phenomena seem to be closely connected to figural properties not captured by the neural interaction account. The test pattern’s apparent contrast can also be described in terms of the maximum and minimum brightnesses of it elements. We find that uniform bright patches are brighter and dim patches are dimmer on low contrast surrounds that on high contrasts; this is hard to reconcile with patternspecific neural interactions.

© 1991 Optical Society of America