Somnology Somnology Somnology is the scientific study of sleep. It includes clinical study and treatment of sleep disorders and irregularities. Sleep medicine is a subset of somnology. After the invention of the EEG, the stages of sleep were determined in 1936 by Harvey and Loomis, the first descriptions of delta and theta waves were made by Walter and Dovey, and REM sleep was discovered in 1953. Sleep apnea was identified in 1965. In 1970, the first clinical sleep laboratory was developed at Stanford. The first actigraphy device was made in 1978 by Krupke, and continuous positive airway pressure therapy and uvulopalatopharyngoplasty
Sexual selection in humans between hormone levels and partner selection among humans. In a study measuring female attraction to males with varying levels of masculinity, it was established that women had a general masculinity preferences for men's voices, and that the preference for masculinity was greater in the fertile phase of the menstrual cycle than in the non-fertile phase. There is further evidence from the same study that in fertile stages of the menstrual cycle, women also had a preference for other masculine traits such as body size, facial shape, and dominant behavior, which are indicators of both fertility and health. This study did