Culture and menstruation the ideal of synchronised tidal, lunar, menstrual and seasonal periodicities whose overall harmony (it is believed) confers spiritual power and fertility. To many, such cultural associations appear persuasive in view of the fact that in humans, the menstrual cycle quite closely approximates the moon's 29.5-day synodic cycle, unlike in chimpanzees (~36 days) or bonobos (~40 days). Statistical information from hunter gatherers is lacking, but where large-scale western studies focus on women's peak reproductive years—removing outlier values—the cycle length gravitates around 29.1–29.5 days, while the figure for women in their thirties shortens toward 28 days. In no extant human population has
Menstrual cycle it has been found that women in the follicular phase demonstrated better performance in tasks that contain empathetic traits. Fear response in women during two different points in the menstrual cycle has been examined. When estrogen is highest in the preovulatory stage, women are significantly better at identifying expressions of fear than women who were menstruating, which is when estrogen levels are lowest. The women were equally able to identify happy faces, demonstrating that the fear response was a more powerful response. To summarize, menstrual cycle phase and the estrogen levels correlates with women’s fear processing. However, the examination of