Measured onset and offset RT to a long and a short wave band in both the fovea and periphery in 3 male graduate Ss. The wave bands were selected with the intention of isolating foveal and peripheral systems. RT to onset stimulation on the periphery is significantly faster than to offset. The difference between onset and offset RT in the fovea was not significant. On-off differences are independent of wavelength. Because a common function for intensity, independent of wavelength, existed in the periphery and in the fovea only when correction was made in the peripheral data for the peripheral luminosity function, it appears that those data, with their on-off differences, reflect the activity of the peripheral (rod) system. (PsycINFO Database Record (c) 2006 APA, all rights reserved). © 1968 American Psychological Association.
