Adaptation in the long-wavelength pathways.

We describe and test predictions of a model of long-wavelength test sensitivity upon large, uniform backgrounds. The model explains changes in sensitivity in the red-green detection pathways strictly based upon losses of sensitivity in the receptors. We derive the prediction that field mixture data for field-mixtures of mu1 (fixed) and an addend, mu 2, must follow the same shape on different intensities of the fixed background, mu 1. This prediction is not in good agreement with the measurements.