The Evolution of Plasticity in Female-Female Desire

Abstract Previous psychological and anthropological research suggests that female-female desires show greater variability and plasticity than do male-male desires. I argue that plasticity in female-female desire has its origins in the evolved independence between female proceptivity (i.e., motivation to initiate sexual activity) and female arousability (i.e., capacity to become aroused to sexual stimuli), which evolved in concert with the loss of a circumscribed and observable period of estrus in higher primates. Proceptivity is an intrinsically cyclical system, peaking during ovulationwhen estrogen levels are highest, whereas arousability is continuous and hormone-independent. Because female proceptivity peaks only a few days per month, a relatively greater proportion of women's day-to-day desires is governed by arousability. The opposite is true for males, who experience continuously high proceptivity mediated by their continuously high androgen levels. Moreover, because arousability is a responsive rather than an initiatory system, there would have been little evolutionary benefit to “orienting” this system exclusively toward other-sex partners. Therefore, arousability likely permits sexual desires for both sexes. Women will consequently have more opportunities than men to experience situationally-triggered same-sex desires, regardless of their underlying sexual orientation. The implications of this perspective for understanding different manifestations of same-sex sexuality are discussed. doi:10.1300/J056v18n04_01