Selective influence of menstrual cycle on perception of stimuli with reproductive significance

Sixteen healthy women (20-32 years) not taking oral contraceptives were tested at three phases of their menstrual cycles (menses, preovulatory phase, and midluteal phase). Another 16 women taking oral contraceptives served as age-matched controls, and were tested during menses and during phases corresponding to the preovulatory and midluteal phase. On each test occasion, perception was assessed of visual stimuli belonging to three categories: sex (nude men), babies, and stimuli related to body care. Also, meaningless syllables were given. Stimuli were presented by a tachistoscope. Presentation of each stimulus was repeated until the subject signaled recognition. Trials to recognition and correctness of the recognition response were recorded. In spontaneously cycling women effects of the phase of the menstrual cycle depended on the stimulus meaning: During the preovulatory phase, there was an increase in the number of correctly recognized sex stimuli (p < 0.05) and of stimuli falsely recognized as sex stimuli (p < 0.05). The number of stimuli falsely recognized as body care was reduced during this phase (p < 0.05). Moreover, during the luteal phase, the number of trials to recognition of baby stimuli was diminished (p < 0.01). In women taking contraceptives, no stimulus specific changes occurred, but correct recognition was generally improved during the luteal phase. Rather than supporting a general influence of the normal menstrual cycle on perceptual functions, the present results demonstrate that the effects of the menstrual cycle depend on the meaning of the stimulus with the perception of sexual stimuli, but not of stimuli related to maternal nurture, being improved during the preovulatory phase.