while studying at colombia, leta stetter hollingworth became interested in the misconceptions about women that seemed to be a part of the zeitgeist. thorndike agreed to supervise her dissertation on functional periodicity, which focused on the idea that women are psychologically impaired during menstruation. thorndike greatly influenced the work of leta hollingworth as he was a supporter of the variability hypothesis. the variability hypothesis postulated that, because men exhibit a greater variation in both psychological and physical traits than women, women were destined for mediocrity while men both occupied the highest and lowest ends of the range on any given trait (shields 1982). hollingworth set out to prove that the variability hypothesis was incorrect and that the extremes were not based on a male genetic superiority, instead extremes were culturally-based. she believed that rather than innate differences, societal roles accounted for the sex differences in the numbers of institutionalized males and females at the clearing house for mental defectives. although the research of hollingworth conflicted with the direct interests of thorndike, she completed her doctorate dissertation beneath his supervision. her dissertation addressed the previously supported concept of women's mental incapacity during their monthly menstruations. for the study, she recorded the results of both women's and men's performances on a variety of cognitive, perceptual, and motor tasks daily for three months. no empirical evidence of a decreased performance with a phase of the menstrual cycle was found. upon receiving her ph.d. in 1916, leta stetter hollingworth accepted thorndike's offer of a position at the columbia teachers college.