Evoked Potentials and Correlated Judgments of Brightness as Functions of Interflash Intervals

Abstract

Computer-averaged evoked potentials were recorded from subjects presented with pairs of flashes having equal light energy but differing in duration of the brief interval separating the flashes. For the experimental conditions studied, the pair was always subjectively fused. Although the brightness did not change noticeably as the interval was varied, the use of the forced-choice psychophysical technique showed that apparent brightness declined with increase in the interval. Analysis of the evoked potentials revealed a correlated change in amplitude and wave form previously demonstrated for changes in flash flux alone.