A quick association exercise. What comes up when you hear the following words:

Competitiveness. Aggressiveness. Violence.

If you think of the word "male", you’re most likely not alone. The above features are frequently attributed to maleness and masculinity. On closer inspection it also becomes clear that male competitiveness, and violence are often directed primarily at other males: on the battlefield, on the playing field, in the office, at the bar, or on the street. Charles Darwin long ago noticed the existence of intra-sexual between males; he also understood that the basic aim of all this male mayhem was to gain the and reproductive favor of females.

Influenced by Darwin (and by the fact that until recently most researchers were men), most of the research into intra-sexual competition has focused on the struggle between men to gain sexual access to women. Only in the 80s did science begin to investigate in earnest the same phenomenon on the other side of the divide: female competition for a suitable male. A host of studies in recent years have shown convincingly that the traditional view of women as passive and uncompetitive is wrong. Women, it turns out, are engaged in a competition of their own, aggressively jockeying for position in a battle to secure a suitable mate.

According to evolutionary theory, intra-sexual competition will concern mainly those traits that are attractive to the opposite . The American evolutionary psychologist David Buss found in the eighties that intra-sexual competition takes two primary forms: self-promotion and competitor derogation. Men demonstrate and promote their physical abilities and social status (masculine traits favored by women). Women tend to promote their youth and physical (feminine traits favored by men). Men try to derogate their rivals by disparaging their economic and physical strength, while women criticize the age, appearance and character of their opponents.

Building on David Buss’s pioneering work, the Canadian researchers Maryanne Fisher and Anthony Cox discovered a few years ago two additional tactics commonly used in intra-sexual competition: mate manipulation and competitor manipulation.

Mate manipulation involves trying to end the race early when we are still in the lead, before our competition catches up. An example: If your boyfriend visits you at the office often, and then a very attractive and available coworker joins the office in a cubicle next to yours, you may be motivated to ask your guy to stop visiting you at work.

Competitor manipulation is analogous to arguing that a movie is not worth the price of admission. This can be achieved by bad mouthing the movie (for example if you tell someone bad things about the guy you're interested in) or raising the price of the ticket (as when you spend lavishly on your date to discourage competitors who can’t afford to match your largesse).

According to Joyce Benenson, a researcher at Emmanuel College in Boston, competition among women has three unique characteristics: first, because they have to protect their bodies from physical harm (so as not to interfere with present or future and childbirth), women rely on veiled aggression towards other women (behind verbal gymnastics or under cover of the group) rather than physical confrontation.

Second, high status and very attractive women need less help and protection from other women and are less motivated to invest in other women (who represent potential competition). Thus, a woman who tries to distinguish or promote herself threatens other women and will encounter hostility. According to Benenson, a common way women deal with the threat represented by a remarkably powerful or beautiful woman is by insisting on standards of equality, uniformity, and sharing for all the women in the group and making these attributes the normative requirements of proper femininity.

Third, in extreme cases women may guard against potential competitors by means of social exclusion. If a new attractive woman shows up in the neighborhood (or school, or club), all the women in attendance may turn their backs on her, compelling her to withdraw from the scene, thus increasing their own chances with the surrounding males.

A number of recent studies provide further support for the existence of the 'female competition' phenomenon. For example, Jon Maner and James McNulty of Florida State discovered that women's levels went up when they (unknowingly) smelled t-shirts of ovulating young women, presumably in preparation for aggressive competition. Canadian researchers Tracy Vaillancourt and Aanchal Sharma, showed how women judge and condemn each other based on appearance. They arranged for female participants to interact with a young research assistant. Some of the participants saw the assistant dressed in revealing clothes while others saw her wearing jeans and a T-shirt. The researchers tracked participants’ responses to the assistant during the meeting and after she left the room. Results: The assistant was unanimously criticized when she wore revealing clothes and largely ignored when she wore regular attire. This study (and others) supports the evolutionary prediction: a more attractive woman (i.e., one who has more of what men like) will receive more hostility and less from other women because her presence threatens their own access to the evolutionary prize.

A central arena for competition between females is sexual behavior itself. Studies show that women tend to criticize and reject other women who are viewed by them as sexually promiscuous. The researcher Zhana Vrangalova and her colleagues at Cornell University recently surveyed 750 college students about their sexual behaviors and attitudes. Then, participants read a short description of a hypothetical person (of their own sex) who had either two (nonpermissive) or twenty (permissive) past sexual partners. Participants then rated this potential friend on several -relevant outcomes. Results revealed that female participants, regardless of their own level of permissiveness, overwhelmingly preferred the nonpermissive potential friend. According to the researchers, this is because women want to guard their partners and because they socal stigma: if you go around with someone who’s known to be promiscuous (a “slut”), there is danger that the label will latch on to you, too.

This study and others align with the observation that women are often the chief enforcers of strict and sometimes cruel norms of female appearance and sexual behavior. For example, the ritual of female genital mutilation, still practiced in some Muslim countries in Africa, is primarily designed to make the girl into good ‘bride material’ for men. To that end, clitoridectomy reduces her ability to enjoy sex and therefore decreases the likelihood she’ll be tempted to her husband. Sewing the vaginal opening shut, which is often performed after the genital , reduces the possibility that the girl will have sex before , again benefitting the interests of the future husband. Still, this ceremony is managed, performed and enforced by women (mostly mothers and grandmothers).

Another example: Girls’ foot binding was a custom in China for over a thousand years (until it was outlawed in the early twentieth century). The ancient custom (which involved breaking the toes of the baby, folding them and binding the feet tightly for years) was valued primarily because women with small feet were considered more desirable sexually (in the eyes of men) and because a wife’s tiny, useless feet were evidence of the husband’s wealth (‘I’m so rich my woman doesn’t need to work; indeed she can’t’). In this case too, the main enforcers and managers were mothers and grandmothers.

The evolutionary explanation for these phenomena relies on the assumption that sex with a woman (and thus access to her uterus) is a biologically desirable and scarce resource for men. Among women of childbearing age, reducing the sexual 'supply' increases female bargaining power in the relationship economy. Thus, it pays for women to enforce sexual conservatism even at the cost of ostracizing and manipulating other women identified as permissive. Mothers and grandmothers, by the same logic, have a strong incentive to ensure that their daughters (who carry their ) will become highly attractive to men, even at the price of causing them early suffering and mutilation.

Feminist psychology, however, argues that competition among females is driven primarily not by biological imperatives but rather by social mechanisms. According to this argument, cutthroat female competition is due mainly to the fact that women, born and raised in male-dominated society, internalize the male perspective (the “male gaze”) and adopt it as their own. The male view of women as primarily sexual objects becomes a self-fulfilling prophecy. As women come to consider being prized by men their ultimate source of strength, worth, achievement and identity, they are compelled to battle other women for the prize.

In this sense, the feminist approach argues in effect that many women are beset by what Karl Marx called, 'false consciousness.' According to Marx, a factory worker who’s convinced that his enemy is another worker looking for a job has false consciousness because he does not understand that the true enemy is the owner of the factory, who sets workers against each other in order to subjugate them both and get rich on the value of their labor. Many women, according to this argument, refuse to see that the real threat to their achievement, power, value, and identity are not other women, but the male establishment that controls their lives.

Either way, female competition has a price, and not only on the political level. This competition produces much of the that interferes with the of many women, especially young ones. Studies show that compared to men, women tend to be more sensitive to emotional information and are better at decoding subtly encoded social and interpersonal messages. In addition, women's sense of is based more on their friends’ opinions of them. This combination of acute awareness of--and sensitivity to--subtle social cues renders women more vulnerable to indirect interpersonal aggression.

For example, the researcher Christopher Ferguson of Stetson University in Florida and his colleagues asked participants to watch two television programs (with a svelte and chubby female star) and interact with a woman (in attractive or casual attire). They found that participants’ mood and were not affected by the TV shows but significantly affected by the live encounters. Interacting with an attractive woman dressed in flattering clothing led the participants to feel distressed and negative about their bodies, especially if the encounters were held in the presence of an attractive man.

At the end of the day, the tendency to engage in intra-sex competition appears to be a part of our genetic hardware and a feature in the heritage of human culture. Our genes and social habits are not easy to change, certainly not overnight. But the first step toward changing a habit is becoming aware of it. To that end, men may want to ask whether ‘getting the girl’ is worth the spilled blood and broken bones, while women may do well to reflect on whether the goal of getting a man (and his sperm and support) justifies the competitive tactics of manipulating, shaming or ostracizing other women and the pain it causes them.