Menstrual cycle, arousal-induction, and intelligence test performance

Regularly menstruating students (aged 19 to 25 yr.) were tested in the morning under high and low arousal-induction conditions (with time-pressure instructions vs without time-pressure instructions) during either midcycle (n = 16 or menstruation phase (n = 16) to study the interactive effects of menstrual phases and time-pressure stress-induced arousal on intelligence test scores on Raven's Standard Progressive Matrices and Hundal's General Mental Ability Test. A crossover interactive effect of menstrual phase and stress-induced arousal was found on performance of the Hundal test, suggesting that performance of subjects who were tested during the midcycle phase (putatively High Basal Arousal) was impaired under the time-pressure instructions condition (High-induced Arousal) as compared to performance under the without time-pressure instructions condition (Low-induced Arousal), with the reverse pattern of effects being true for subjects who were tested during the menstruation phase. Scores on Hundal's test conform to the Yerkes-Dodson (1908) law which relates arousal to task performance and suggests that the menstrual cycle and performance on the intelligence test was arousal-based. No effects, however, were observed for Raven's Matrices, raising the possibility that task characteristics may mediate the relationship between arousal and performance.