Menstrual, diurnal, and activation effects on the resolution of temporally paired flashes.

Abstract

ABSTRACTNormal female Ss were tested for the discrimination of paired flashes in the mornings and evenings of 3 days during the menstrual cycle, under both resting and activation conditions. The threshold for fusion was highest at the premenstrual point and in the evening. A signal detection analysis indicated that the threshold change was the result of a change in criterion placement and not a change in sensory sensitivity as required by a biological clock hypothesis. No interactions were apparent for the three arousal variables.