Visual Adaptation: Increased Efficiency Resulting from Spectrally Distributed Mixtures of Stimuli

Visual adapting stimuli having different spectral distributions are used alone and then mixed together. It is found that the mixture is more effective, as an adapting field, than either component when used alone. This experiment, along with others, supports the following: although the most efficient stimulus for eliciting a visual sensation is "compact" in space, time, and wavelength, the most efficient adapting stimulus tends to be dispersed in each of these dimensions.