Colored aftereffects contingent on patterns generated by Lie transformation groups

Abstract

Two experiments are described which make a preliminary test of the power of the Lie transformation group model of neuropsychology (LTG/NP) in predicting pattern-specificity of visual aftereffects of color. In Experiment 1, each of three groups of eight subjects reported contingent aftereffects (CAEs) of color following induction with one of the three pairs of static representations of first-order Lie orbits, these patterns having been presented alternately (one in red light and one in green) every 9.5 sec during a 10-min adaptation period. This result demonstrates that CAEs can be subserved by each of the three pairs of elementary patterns generated by the LTG/NP. In Experiment 2, induction occurred to all three pairs of elementary Lie patterns in sequence. Eleven of the 12 subjects reported color aftereffects, five subjects on patterns from all three pairs, indicating that several pattern-specific aftereffects of color can coexist in an individual observer. Together, these results suggest that the LTG/NP is of value in describing the mechanism of CAEs, which are taken here to be subserved not by visual "molecules," such as edges or dipoles, but rather by global vectorfield properties of patterns. © 1985 Psychonomic Society, Inc.