Ovulatory shifts in female sexual desire

Journal of Sex Research, Feb, 2004 by Elizabeth G. Pillsworth, Martie G. Haselton, David M. Buss

Given the profound reproductive importance of mate choice, female sexual psychology has likely been shaped by reproductive constraints and opportunities. The high energetic costs of pregnancy and an extended period of juvenile dependency in humans have limited the total lifetime reproductive output to only a few offspring (Daly & Wilson, 1983; Low, 2000). In modern hunter-gatherer communities, for example, lifetime reproductive output ranges from a low of about 4.5 children among the !Kung of Southern Africa to just over 8 children among the Ache of Paraguay (Hawkes, O'Connell, & Blurton-Jones, 1997; Hill & Hurtado, 1996; Howell, 1979). Moreover, opportunities for conception are restricted to a small window within a woman's monthly cycle (Wilcox, Weinberg, & Baird, 1995), and over the long course of human evolutionary history, such ovulatory events necessarily would have been rare in a woman's life. Most women of reproductive age spent many years pregnant or lactating, states that suppress ovulation (Symons, 1995). High infant mortality required more frequent pregnancies to reproduce successfully. Menarche occurred later in life, shortening ancestral women's reproductive years compared with those of modern women. Earlier age of death abbreviated the reproductive span. In women living today, ovulation is sometimes a monthly event that recurs for roughly 2 decades, resulting in perhaps 200 to 300 hundred ovulatory episodes. In ancestral women, older age of menarche, frequent episodes of pregnancy, many years of lactation, and shorter lifespans would have drastically reduced the number of these episodes to perhaps as few as a dozen, rendering each of vital importance. Given its significance, it would be surprising if selection had not fashioned specialized adaptations in women to guide mating decisions surrounding the time of ovulation. In this article, we propose that specific design features of female sexual desire have been shaped by selection and function to regulate shifts in the intensity and object of desire linked to the ovulation cycle.

Sexual desire should be clearly distinguished from sexual activity (Regan & Berscheid, 1999; Symons, 1979). Sexual behavior can occur or not occur for many reasons other than sexual desire: to accommodate a mate's wishes, to fulfill a perceived obligation, to express love, or as a consequence of coercion (Impett & Peplau, 2003). Sexual desire, in contrast, can be conceptualized as a motivational and regulatory adaptation. In both sexes, desire might have evolved design features that motivate selecting an appropriate mate (the object of one's desire) and judiciously timing the occurrence of sexual intercourse. In this research project, we explored several hypothesized functions of sexual desire for women and tested predictions based on these hypothesized functions.

THE TIMING OF WOMEN'S SEXUAL DESIRE

Although researchers have been examining the relationship between the menstrual cycle and fluctuations in female sexual desire for almost a century (see Hedricks, 1994; Regan & Berscheid, 1999; Schreiner-Engel, 1980, for reviews), this research has largely been carried out without being explicitly informed by evolutionary theories of human mating. The results are often inconsistent. Although most of the previous research on the topic has discovered distinguishable peaks of sexual desire within the menstrual cycle, there has been little consensus about the cycle phase in which this is most likely to occur. Some studies find peaks during nonconceptive phases of the cycle (e.g., Bancroft, Sanders, Davidson, & Warner, 1983; Englander-Golden, Chang, Whitmore, & Dienstbier, 1980; Shader, Dimascio, & Harmatz, 1968; Warner & Bancroft, 1988), and others find peaks at or around ovulation (e.g., Cavanagh, 1969; Dennerstein, Gotts, Brown, & Morse, 1994; Stanislaw & Rice, 1988; Van Goozen, Wiegant, Endert, & Helmond, 1997).

One difficulty in interpreting the results of previous research is the wide range of methods and measures that have been used. Researchers have examined widely varied phases of the cycle. Across different studies, the menstrual cycle has been divided into two (e.g., Hertz & Jensen, 1975), three (e.g., Englander-Golden et al., 1980), four (e.g., Graham & Sherwin, 1993), five (e.g., Hart, 1960), and six (e.g., Bancroft et al., 1983) phases. Furthermore, the chosen phases have been assessed using a variety of different methods. Many studies have left cycle phase determination up to the participants, who relied solely on broad categories provided by the researchers, such as "premenstrual," "post-menstrual," or simply "associated with your period" (e.g., Graham & Sherwin, 1993; Hart, 1960; Warner & Bancroft, 1988). Recent studies have used improved measures to determine cycle point, such as methods used to estimate specific cycle day (Penton-Voak & Perrett, 2000; Thornhill & Gangestad, 1999) and physiological methods including basal body temperature (BBT; e.g., Church, Hedricks, LeFevre, & McClintock, 1994; Stanislaw & Rice, 1988), blood assays (e.g., Slob, Ernste, & Van der Werff ten Bosch, 1991; Van Goozen et al., 1997), cervical mucus characteristics (e.g., Church et al., 1994), and urine tests (e.g., Dennerstein et al., 1994).