CHAPTER 5
To Masturbate or Not to Masturbate
In this chapter, I ask and perhaps answer a series of seemingly dumb questions about masturbation. I do so to try to understand masturbation as a sexual phenomenon, but also to understand some of the variability in asexuality.
My first dumb question is this: What is the purpose of masturbation? This first question about the rather delicate subject of masturbation is, at least on the surface, “dumb,” because there is, of course, in many people’s minds no real purpose to masturbation, aside from simple pleasure; it just feels good, and that’s why people do it. But from an evolutionary standpoint, it is a good question, because the existence of any form of sexual variability without clear reproductive benefits (e.g., homosexuality, asexuality, and masturbation) puzzles scientists. After all, how could a sexual variation without potential procreative sustainability compete with one—heterosexual intercourse—that has obvious and built-in procreative sustainability (the replication of genes in the form of children) over millions of years of human evolutionary history? So, masturbation seemingly serves no obvious reproductive purpose, yet it exists. Thus, masturbation misses the (evolutionary) point. (And sometimes, in the case of men, messes the point.)
So the answer, “because it feels good,” begs another question: Why does it feel good? Or, at least, why does it feel good enough to make people do it, even sometimes when there is an available partner? Before we answer this question, let’s give a little background on the incidence and frequency of masturbation. In the classic survey conducted in the United States by the pioneer sex researcher Alfred Kinsey, nearly all the men and about 60 percent of the women indicated that they had masturbated at least once (Kinsey, Pomeroy, & Martin, 1948; Kinsey, Pomeroy, Martin, & Gebhard, 1953). Indeed, one of the great cultural shocks of the 1950s, summarized in Kinsey’s book Sexual Behavior in the Human Female, was that a majority of women had masturbated. Today, people are less likely to see this fact as a revelation and more, perhaps, as a titillating curiosity. A well-conducted national survey of the United States in the 1990s, the National Health and Social Life Survey, sometimes considered the modern follow-up to Kinsey’s work, indicated that 75 percent of women had masturbated (Laumann, Gagnon, Michael, & Michaels, 1994). So, there is support for the notion that masturbation is a common recreation, rivaling—dare I say?—baseball (or hockey if you’re from Canada) as a national pastime.
Returning to our original question, what is the purpose of masturbation? It is true that masturbation does, for most people, feel good and thus serves “the purpose” of pleasure enhancement. It is also true that other factors, including the availability of a partner, can influence masturbation frequency. So, some people do it, partly as a substitute for an unavailable partner.[20]
Beyond these perhaps rather obvious reasons, the ubiquity of the act suggests that masturbation may be evolutionarily adaptive or serve a reproductive “function,” or at least not be detrimental to one’s reproductive success. Indeed, there is likely a purpose to masturbation beyond mere pleasure enhancement or replacement for a lack of sexual partner. In adolescence or young adulthood (particularly if accompanied by fantasy), it may serve as a form of sexual “rehearsal,” or a kind of mental acting out of sexual scenes (First I’ll kiss her like this, then I’ll stroke her like that…). Thus, it may create or at least reinforce important sexual scripts, potentially to be played out with partners later on in life (see also chapter 2). In other words, as an actor learns his role—what he needs to say and do—from a TV script, we learn potentially adaptive sequences of behavior, along with how to deal with behavioral contingencies (If this happens, do this; if that happens, do that…), partially through fantasies.[21]
Sometimes the fantasies are mere snippets of what, in real life, would comprise a longer sequence of behavior. So, for a heterosexual male adolescent, it may be as simple as imagining kissing a woman, stroking her inner thighs, and rubbing her vulva. These imaginings may ingrain into his psyche a short sexual script, the elements and order of which would be adaptive to act out if he were to encounter an opportunity to engage in sexual behavior with a member of the other sex.
Sometimes the imaginings are more elaborate. So, a young heterosexual man may have elaborate “harem-like” fantasies of having a bevy of beautiful young women as playthings at his sexual beck and call. If a heterosexual man ever had a chance to encounter and then enter this situation (i.e., to be a harem master), it would be, at least from an evolutionary perspective, a good idea for him to act out this script, as it would be a procreative gold mine: men’s genes would be replicated at a high frequency by mating with many young women. Men have a relatively low reproductive/parental investment (e.g., lots of sperm that are easily replaced), so, from the perspective of procreation, it is in a man’s interest to sow his seed among as many reproductively viable women as possible (Buss & Schmitt, 1993; Symons, 1979; Trivers, 1972). Conversely, women have a relatively high reproductive/parental investment (e.g., must gestate a fetus for nine months inside her own body), so it is usually in their best interest to be picky sexually, potentially securing a man’s resources to help with raising their offspring and only mating with men of high-quality genes. Thus, it would be in an average heterosexual woman’s advantage to form a sexual/romantic bond with, say, Brad Pitt if she had the opportunity in real life, given the high quality of his genes (My gosh, is he cute!) and his excellent resources (My gosh, is he rich!). So, a young woman’s fantasies about Brad Pitt or similar men, even if they might irk her husband (if he knew), would be adaptive, as they help in rehearsing reproductively beneficial actions/scenes in case she ever encountered them.
In sum, it is not surprising that men and women create or are drawn to fantasies of this kind: they help to create or reinforce sexual scripts that, if they unfolded in real life, could be a huge boon, reproductively speaking.[22]
Masturbation may also have physical health benefits. Men’s prostate health later in life may be related to frequency of masturbation early in life (Walsh, 2004). Thus, frequent “flushing out” of the prostate gland (an important internal reproductive organ providing some of the content of semen) in early adolescence and young adulthood may serve a man well, although there is some conflicting evidence of this benefit (Dimitropoulou et al., 2009). Masters and Johnson (1966) argued that, for women, masturbation can be a good remedy for pelvic congestion, which contributes to menstrual cramps and tension. Similarly, men may also derive some relief through masturbation from muscular tension and pelvic congestion caused by sexual arousal. This explanation for masturbation—relief from tension and congestion—partly blurs the distinction between health and pleasure, as tension reduction is potentially healthy, but it also can be pleasurable. Finally, there is some evidence that sexual activity, including masturbation, is associated with heart health (Davey, Frankel, & Yarnell, 1997).
20
However, note that a lack of a partner is not a good proxy for high frequency of masturbation, as sexual behaviors tend to correlate with one another, so those who have frequent sex with a partner also, on average, masturbate more. But the main point here is that masturbation can, at least for some, serve as a substitute for an unavailable partner.
21
Masturbation, then, is like all “play” activity in that it is more frequent in younger versus older people, but the seeming insignificance of the act belies the fact that it partially prepares one for later, adult-oriented challenges. Thus, it is not surprising that our fantasies often match or closely resemble what might be best for us from an evolutionary perspective, even if this fantasy world never exists in real life.
22
Even though our fantasies often resemble what might be “best” for us, at least from an evolutionary perspective, modern society also has the capacity to make our fantasies maladaptive. The modern media, with their high-tech sophistication and super-realistic images, may make our fantasies more real and powerful than our brains could ever conjure. Thus, along with ingraining sexual scripts, modern media probably raise our expectations and, at times, make us too unrealistic about what to expect in real-life sexual encounters. Thus, these fantasies may be somewhat maladaptive in modern society, even if they would have been adaptive in in our evolutionary past. After all, realistically, we can’t all mate with Brad Pitt!