Menstrual cycle affects kinesthetic aftereffect, an index of personality and perceptual style.

Research suggests that kinesthetic aftereffect (KAE) scores reflect status on a postulated stimulus intensity modulation (SIM) mechanism that damps down subjective stimulus intensity for some (reducing) and increases it for others (augmenting). Such a mechanism would help account for empirically observed individual differences in such behaviors as pain tolerance, sensory deprivation reactivity, and stimulation seeking. It was hypothesized and confirmed in three adult female samples that KAE varies curvilinearly over the menstrual cycle: Greater KAE reduction occurs at the cycle's beginning and end. Neither tiredness, oral contraception, medication, attention, nor social expectations can explain this finding. Of the behaviors studied in the KAE literature, only five are also encompassed by the menstrual cycle literature. Four of these (antisocial behavior, acute schizophrenic episodes, accidents, and activity level) show similar curvilinearity over the cycle. We hypothesize that cyclical variation in the SIM mechanism mediates the curvilinear pattern observed for both these four behaviors and KAE.