By Catherine A. Sanderson, Amherst College
Just like eating, another behavior that is clearly motivated by both biological and social factors, is sex. Within the field of psychology, the earliest work examining sexual behaviors was conducted by Alfred Kinsey and his colleagues. In the late 1940s, they gathered data on sexual activities and preferences from more than 18,000 people across gender.

What Motivates Us to Have Sex?
In the 1960s, a research, which involved both observing sexual behavior and monitoring physiological changes during sexual arousal, was conducted by William Masters and Virginia Johnson. It was considered to be one of the most well-known research on sexual behavior. It marked the first scientific effort to help diagnose and treat sexual disorders and dysfunction. Their work was described in their best-selling book, Human Sexual Response.
The motivation to have sex is, of course, nature’s clever and pleasurable way of making people procreate. Nonetheless, sex also leads to other benefits. It fulfils a need for connection, intimacy, release of sexual tension, and so on.
In fact, a 2016 study found that engaging in more frequent sex—at least up to once a week—is associated with greater overall well-being. More than once a week doesn’t lessen satisfaction, it just doesn’t lead to even more satisfaction, once couples have reached the once a week break-even point.
This article comes directly from content in the video series Introduction to Psychology. Watch it now, on Wondrium.
Gender and Sex hormones
Sex hormones activate our interest in engaging in sexual behavior, but this works differently in men and women. Male sex hormone levels for testosterone tend to remain at a consistent level. For women on the other hand, sex hormone levels for estrogen shift over time, but constantly peak each month during ovulation, when fertility is at its highest. This finding makes sense at a biological and evolutionary level.
Understandably, men can father a child at any point during a month, so it makes sense that their sexual interest remains consistently high. Whereas for women, who are able to conceive can only do so during a few days each month, it’s important that they are actually motivated to have sex during that time; hence the increase in hormones that produce sexual desire during ovulation.
Conversely, women after menopause, while not losing interest in sex, no longer experience sexual desire as fluctuating on a regular monthly cycle.
Casual Sex
Men and women also show pretty consistent differences in their attitudes about casual sex. In one classic demonstration of this difference, published in 1989, but based on data collected in 1978 and 1982, researchers at Florida State asked students to walk around campus and randomly approach other students of the opposite sex—assuming most students are heterosexual—and ask them if they’d be interested in a one-night stand with them that evening.
So, who agreed? Interestingly, first, none of the women were interested—literally zero percent. But, out of the men who were approached by a woman, 75 % acquiesced. And most of the remaining 25% didn’t exactly refuse either. Many basically asked for a ‘raincheck’, saying that that night just really wasn’t good on their end.

Some psychologists believe that men’s greater interest in casual sex and having multiple partners is fundamentally based on evolutionary theory, as well as the different strategies men and women are presumed to have needed to use, to pass on their genes. As women spend considerable time pregnant and nursing, they clearly are, as they should be, motivated to form a stable relationship with a single person, who will help ensure the survival of their children by providing food, shelter, protection, and so on.
A Sexual Double Standard
Men, on the other hand, based on evolutionary theory, should be motivated to have sex with as many different people as possible, because each act of sex increases the odds that their genes will be passed on.
However, other researchers believe that these gender differences are largely a result of social norms, not biology. A sexual double standard, in which male sexual behavior tends to be encouraged more than female sexual behavior, continues to exist, even if it has weakened somewhat. Both men and women consider casual sex more acceptable for men than for women, and a 2019 study found this to be true even when the person being evaluated is a friend or acquaintance.
Hence, clearly, it’s not surprising that women report less interest in casual sex and are more wary of opportunities for one-night stands, as corroborated by the Florida State study, given the potential for such behavior to be seen in a negative light.
Common Questions about Factors that Influence Sexual Behavior
Research, which involved both observing sexual behavior and monitoring physiological changes during sexual arousal, was conducted by William Masters and Virginia Johnson in the 1960s.
Some psychologists believe that men’s greater interest in casual sex and having multiple partners is fundamentally based on evolutionary theory, as well as the different strategies men and women are presumed to have needed to use, to pass on their genes.
A sexual double standard, in which male sexual behavior tends to be encouraged more than female sexual behavior, continues to exist, even if it has weakened somewhat.