Verified by 
This article is a transcript of my TEDx talk. You may watch my talk here.
We are all going to die. Paradoxically, sex, which is the source of life, keeps reminding us of our mortality. When I started my graduate studies, I wondered which topic would fascinate me in the upcoming years. Because I was young and at the height of discovering the joy of life, the answer was easy: Sex. Of course, I discussed sexual issues with friends and people around me and was surprised to discover that sex could be not only a source of joy and pleasure but also a source of pain, embarrassment, or even boredom. I remember that one of my friends told me, "I don't understand all the fuss around sex!" I asked her if she didn't enjoy her sex life and she replied that she did, but that for her, it wasn't a big deal. Then, I decided to explore the meaning of sex in people's lives and how it affects their relationships.
Now, let's find out why sex may pose a problem for humans and how humans cope with it.
As we all know, we are equipped with a sexual system that enables us to reproduce and transfer our genes to the next generations. The sexual system arouses our sexual urges and thereby motivates us to find a partner with whom we can mate. Without having fun while engaging in sex or, at least, without being motivated to engage in sex, our species wouldn't have survived.
If so, why do so many people have mixed emotions about sexuality? Sex is a creaturely act that reminds us of our animalistic nature. I once visited the San Diego zoo with friends and we watched the chimpanzees. Many of the chimpanzees were copulating with each other, and our presence did not interfere with their "show." One of my friends noted: "Oh! I look like a monkey when I'm having sex." And we all laughed because she was right. We do look like animals when we have sex.
This resemblance reminds us of our animalistic nature and that, like all animals, we are doomed to perish. Animalistic sex reminds us of our own mortality. Just to illustrate the association of sex with death, think about the expression "la petite mort," little death, which may relate to reaching an orgasm.
We may have sex like animals and die like animals do. However, unlike animals, we are aware of the fragility of life and the certainty of death. And this awareness is terrifying and unbearable. To maintain our peace of mind, we use psychological defense mechanisms that help us distinguish ourselves from animals and thereby remove the awareness of death from consciousness.
One such coping mechanism is infusing sex with meanings that transform an animalistic urge to something larger than everyday lives. In one of my studies, I asked people to describe the meanings of sex in their lives. People describe a variety of meanings that make sex much more than a creaturely act. For example, some people may say that for them, sex is a way to express uniqueness and creativity. Others may view sex as a place where they can lose inhibitions and escape reality.1
Think about your reasons for engaging in sex. Why do you have sex? Your impulsive reaction might be: "I want to have sex because I'm horny." However, when asked such a question,2 people mention many other reasons for engaging in sex, such as, "I have sex to relieve stress" or, "I have sex to feel good about myself." When we analyze the meanings of sex and the reasons for having sex, we find that among the most common meanings are those that reflect the belief that sexual activity promotes intimacy between partners and enhances their emotional bond.
Both men and women tend to romanticize sex, and it works for them. It helps them hide the threatening association of sex with mortality, as I'll illustrate with an old study: Participants were exposed to either the physical or romantic aspects of sex. For example, they had to think either about the taste of sweat or about feeling close to their partner. Following this exposure, the participants were asked to complete word fragments, such as coff __, which could be either "coffee" or "coffin"; or ki__ed, which could be either "kicked" or "killed." People were more likely to complete words with deadly connotations following exposure to the physical than the romantic aspects of sex.3 These findings tell us that love protects us from the deadly connotations of sex.
Out of all possible meanings of sex that may hide its deadly connotation, as I mentioned before, why do we tend to romanticize sex and associate it with emotional connection? The answer may lie in the exceptionally long period in which children depend on our caring. At what age can they survive without our caring and protection? Throughout our history, kids' survival chances increased tremendously if both parents raised them together. Hence we had to develop mechanisms that motivated us to stay with a sexual partner, at least long enough until our kids could survive without our caring.
If we take a look at the constellation of characteristics that distinguish human sexuality from that of other mammals, we'll find indirect evidence that the sexual system is one such mechanism4. Sexual interactions may help build the emotional connection between partners. Humans, for example, prefer the "missionary" sexual position. This sexual position enables partners to maintain face-to-face, belly-to-belly contact and look into each other eyes during sexual intercourse. Humans also tend to have sex in private and to sleep together afterwards. Such behavioral tendencies instill a sense of closeness between sexual partners.
In addition, the neuropeptide oxytocin, which facilitates emotional bonding, is secreted in humans during foreplay, sexual intercourse, and the moments preceding orgasm. We as humans experience an extended exposure to oxytocin, as we do not limit our sexual interactions to the days that precede ovulation, but engage in sex throughout the menstrual cycle.
We don't have to look at indirect evidence for the role of sex as a relationship-promoter. As I mentioned before, people often indicate directly that they use sex to intensify their relationships. And they act accordingly. For example, people are more inclined to behave in a way that allows them to get closer to potential partners.
In a series of studies,5 we exposed participants to either sexual or neutral stimuli without their awareness. Participants were sitting in front of a computer screen and we flashed pictures on the screen so quickly the participants weren’t aware of them. Half the participants were exposed to erotic photos. Half were shown neutral pictures. Following this exposure, participants met an opposite-sex stranger and were asked to tell this stranger a personal story. Participants who were exposed to sexual stimuli revealed more personal information to the stranger than participants who were exposed to neutral stimuli. This research demonstrates that sexual desire makes us chatty. Chattiness, in turn, helps us initiate a relationship with a potential partner.
In another series of studies,6 participants were exposed to sexual or neutral stimuli. Then, the participants were asked to solve a series of problems in the presence of another opposite-sex participant, who was actually a confederate (a research assistant who worked with us). When the confederate got to the third question, he or she turned to the participants and asked their help in solving that question, uttering, "I'm stuck with this question. Could you please help me solve it?"
The confederate hid a stopwatch in the pocket and assessed the actual time the participants spent helping solve the needed question. The findings showed that participants invested more time in helping the confederate in the sexual activation condition than in the control condition. So sex makes us not only more chatty but also more helpful.
The magical effects of sex work for both men and women, and not only in initial encounters, but also in existing relationships. In a recent study,7 we instructed participants to fantasize about an activity they experienced with their partner, which was either sexual or non-sexual. Then, participants were asked to indicate their desire to do something that would make their partner happy. Participants who fantasized about sex expressed greater desire to do something that would make their partner happy compared to participants who fantasized about non-sexual activity.
And, indeed, people were more likely to behave nicely to their partner after fantasizing about the partner. In a subsequent study, participants who recorded in a diary their daily sexual fantasies and daily relationship interactions for several weeks reported engaging in behaviors to improve their relationship, such as complimenting their partner, following sexually fantasizing about their partner.
What have we learned here? For most people, sex is much more than just sex. Sex becomes complex because we make it so, to distance it from its animalistic and deadly connotations. The association of sex with relationships adds to this complexity because relationships are complicated for so many people.
The next time you have sex, think about your reasons for doing so and the meaning of sex in your life. Asking yourself these questions may reveal the implications of this complexity for your life. The meanings you attach to sex will determine whether sex will be used to develop intimate bonds with sexual partners or just for feeling good about yourself in other ways, which are less beneficial to your romantic relationships. It took me many years to understand that I chose to study sexuality in close relationships to cope with my fear of death, in the hope that my studies will outlive me.
References
1. Birnbaum, G. E. (2003). The meaning of heterosexual intercourse among women with female orgasmic disorder. Archives of Sexual Behavior, 32(1), 61-71. Research Gate
2. Meston, C. M., & Buss, D. M. (2007). Why humans have sex. Archives of Sexual Behavior, 36, 477–507.
3. Goldenberg, J. L., Pyszczynski, T., McCoy, S. K., Greenberg, J., & Solomon, S. (1999). Death, sex, love, and neuroticism: Why is sex such a problem? Journal of Personality and Social Psychology, 77, 1173–1187.
4. Birnbaum, G. E., & Finkel, E. J. (2015). The magnetism that holds us together: Sexuality and relationship maintenance across relationship development. Current Opinion in Psychology, 1, 29-33. Research Gate
5. Birnbaum, G. E., Mizrahi, M., Kaplan, A., Kadosh, D., Kariv, D., Tabib, D., Ziv, D., Sadeh, L., & Burban, D. (2017). Sex unleashes your tongue: Sexual priming motivates self-disclosure to a new acquaintance and interest in future interactions. Personality and Social Psychology Bulletin, 43, 706-715. Research Gate
6. Birnbaum, G. E., Mizrahi, M., & Reis, H. T. (in press). Fueled by desire: Sexual activation facilitates the enactment of relationship-initiating behaviors. Journal of Social and Personal Relationships. Research Gate
7. Birnbaum, G. E., Kanat-Maymon, Y., Mizrahi, M., Recanati, M., & Orr, R. (in press). What fantasies can do to your relationship: The effects of sexual fantasies on couple interactions. Personality and Social Psychology Bulletin. Research Gate
