The Effect of Certain Physiological Determinants on the Flicker-Fusion Threshold

Abstract

Flicker-fusion thresholds (CFF) together with oral body temp. were obtained from 10 normal observers at hourly intervals during 10 working days. Basal metabolic rates were obtained on 9 of the 10 observers and pulse rates on 2 of these observers. Analysis of this material demonstrated that there is a fairly constant diurnal CFF rhythm, the pattern of which is specific for each individual. In 3 out of 10 instances this CFF rhythm was correlated positively with oral temp.; in 5 out of 10 instances it was negatively correlated; and in 2 instances no relationship was found. Various features of the metabolic rate were more highly correlated with the variability of the CFF measures than with the mean of such measures. The relationship between pulse rate and CFF was not clear.