Interrelationships of Background Area, Target Area, and Target Luminance in Their Effect on the Critical Flicker Frequency of the Human Fovea*

Abstract

An investigation was carried out to determine the effects of background area (AB), target area (AT) and target luminance (BT) on the critical flicker frequency of the human fovea, and the interrelationships between these variables. CFF increases linearly with logAB, logAT and logBT. Background area affects CFF much less than target area or target luminance. There are no interactions between the three variables. An index of spatial summation 0.57 was derived from the data and is compared with other indexes of spatial summation given for the human fovea.