Isegoria

I have not been reading the Volokh Conspiracy, but Megan McArdle (née Jane Galt) recently expressed shock over something that came up in a guest-blog by Kingsley Browne, whose new book, Co-ed Combat, argues that women should not fight our nation’s wars.

Browne notes that “advocates of integration of women into combat forces often downplay the sex difference in physical capacity,” then goes on to examine the evidence. Megan’s response:

Is this actually an argument made by large numbers of people? Because it’s completely, obviously insane. Being on the tail end of the size distribution, this realization was perhaps delayed slightly for me — but not past the age of sixteen, when I playfully snatched a hat from the head of a male companion who was a year younger and five inches shorter than I was, only to have him calmly and without visible effort use one hand to pin my arms behind my back while with the other he retrieved his chapeau. I’m both (very) large and strong for my gender, and yet I’m not sure I’ve ever met a (healthy) man who wasn’t stronger than me; even the 130 pound scarecrows I’ve dated were clearly my superiors in physical strength.

Since I’ve seen that exact argument come up numerous times — and I’ve seen the holders of that belief ignore both the evidence of daily life and of quantitative scientific studies — I don’t see it as any kind of silly straw man at all. (Straw person? Person of strawness?)

Browne summons a lot of evidence for the physical differences between the sexes:

Advocates of integration of women into combat forces often downplay the sex difference in physical capacity, correctly pointing out that some women are stronger than some men. In fact, however, there is little overlap between the sexes in terms of strength.

Women, on average, have only one-half to two-thirds the upper-body strength of men. The probability that a randomly selected man will have greater upper-body strength than a randomly selected woman is generally between 95 and 99 percent, depending upon the measure and the sample. Most of this difference is due to differences in the quantity of muscle tissue, a difference attributable primarily to sex hormones.

Although most discussion of physical sex differences focuses on strength, the sexes also differ on a host of other performance measures, such as running speed, aerobic and anaerobic capacity, endurance, and throwing speed and accuracy. These abilities are all potentially important in combat.

Some assert that these large physical differences can be overcome through training. In fact, however, training often increases the sex difference. Both sexes benefit from strength training, and in samples of out-of-shape individuals, women may initially gain more from training than men. Nonetheless, the overlap between the sexes decreases, because training not only increases the strength of both groups, it also decreases the variability within the groups. When males and females both start out in good physical condition, women gain less from further conditioning than men do, so the gap between the sexes actually increases.

Related to differences in strength and bone mass is the high rate of injuries, especially stress fractures, suffered by women in physical training. An extensive study of physical capacity by the British Ministry of Defence concluded that only about 0.1 percent of female recruits and 1 percent of trained female soldiers could satisfy the required physical standards for infantry and armor without sustaining substantially higher rates of injuries than men.

These physical differences still matter:

Modern ground combat still requires substantial physical strength. Today’s infantry soldier often carries between 75 and 100 pounds, and sometimes more. Just his rifle, ammunition, helmet, and body armor can weigh 60 pounds. Add to that food, water, night-vision goggles, various other electronic gear (and the batteries for it), and pretty soon the soldier is carrying a very heavy load — indeed, heavier than that of the soldier of World War II.

After carrying this heavy load, soldiers often must dig in to hard ground for shelter, perhaps in 120-degree heat. If there is concern about chemical or biological agents, as at the outset of the Iraq war, soldiers may have to wear stifling protective gear, which imposes greater physiological stress on women than on men.
[...]
Many combat-support positions also require physical strength. A study conducted in the 1980s found that all Army men in heavy-lifting Military Occupational Specialties (MOSs) were qualified for their jobs, but only about 15 percent of women were. The military has been reluctant to impose strength requirements widely, however, and even if realistic standards were set for particular jobs, adverse conditions often interfere with the neat system of MOSs. “It’s not in my job description” is not a permissible response in a firefight.
[...]
Similarly, if a ship gets struck by a bomb, missile, or mine, all hands may have to turn to the tasks of damage control, such as fire fighting, flood limitation, and evacuation of the wounded. In 1988, after the guided-missile frigate USS Samuel B. Roberts struck an Iranian mine in the Persian Gulf, it came closer than any other U.S. ship since the Korean War to be sunk due to hostile action. Sailors of all specialties turned to fighting the resulting fire and flooding.

Because the captain of the Roberts was concerned that shells would “cook off,” he ordered one of the magazines cleared of ammunition. A “bucket brigade” of fifty sailors — twenty percent of the ship’s crew — passed the fifty-pound shells from man to man. Although the regular job duties of many of these sailors did not require heavy lifting, if the sailors had been unable to perform when necessary, the Roberts would almost certainly have sunk. Yet a Navy study found that almost all Navy women fail the physical standards for critical damage-control tasks, while virtually all men pass.

Browne also has much to say about the psychological differences between the sexes, which he says are milder, with more overlap, but still significant:

RISK PREFERENCE: From toddlerhood on, males have a greater preference than females for risk – especially, but not only, physical risk – a fact reflected in the substantially higher rate of accidental death among boys worldwide and the roughly twelve-fold sex difference in workplace deaths among adults in the U.S. A meta-analysis of 150 risk-taking studies covering subjects of all ages concluded that “males took risks even when it was clear that it was a bad idea,” while females “seemed to be disinclined to take risks even in fairly innocuous situations or when it was a good idea.”

FEAR LEVELS: Risk-taking and fear are intimately related, and females from infancy experience greater fear than males. Sex differences in fear and risk-perception have two components. Women are more likely to perceive risk in a situation than men are, and even when the sexes perceive the same level of risk, women have higher levels of fear.

Psychologist Anne Campbell has argued that sex differences in fear and risk-taking are a consequence of differences in selective pressures acting on the two sexes over evolutionary time. Women have stood to gain less than men from risk-taking, which among men is often related to reproductive competition. Moreover, women have more to lose in terms of reproductive fitness than men, because in primitive societies the death of the mother is a greater blow to the odds of a child’s survival than the death of a father. Indeed, the death of the mother often amounts to a death sentence for her children. Thus, Campbell argues, women’s minds have evolved to rate the costs of physical danger higher than men’s do.

PHYSICAL AGGRESSION AND DOMINANCE: As with risk-taking, sex differences in aggression and dominance appear early in development, being present from about two years of age. Among adults, the clearest evidence for sex differences comes from criminal activity, with men being incarcerated for violent offenses at a rate more than ten times that of women.

Men not only engage in more physical forms of attack, they also have more positive attitudes about aggression. They are more inclined to view it as an acceptable way of achieving one’s ends, and they experience less guilt and anxiety about having acted aggressively than women do.

NURTURANCE AND EMPATHY: Women score higher on most measures of empathy, which, to paraphrase a former president of the United States, consists of the ability to feel someone else’s pain. This greater empathy may be responsible for the heightened guilt and anxiety that women feel about acting aggressively.

The sexes also differ in the circumstances that attenuate empathy, as demonstrated by a recent study examining empathic responses with functional magnetic resonance imaging (fMRI) of the brain. Subjects watched two players playing a game, some players playing fairly and some unfairly. Players were then given electrical shocks.

When a player who had played fairly was shocked, both male and female subjects showed activation of brain areas that respond both to one’s own pain and to observation of pain in others. When an unfair player was shocked, however, the empathic response of male – but not female — subjects was substantially reduced. Areas of the brain associated with reward processing, on the other hand, showed enhanced activation in men, but not women, when the unfair player was shocked. These findings suggest that men’s empathy may be more easily “switched off” and that they may derive greater psychic satisfaction from inflicting harm on those perceived as deserving it.

PAIN TOLERANCE: Although it is commonly asserted that women have a higher tolerance for pain than men — a belief apparently resting on women’s endurance of painful childbirth — a large body of data refutes that argument. Instead, women generally withstand pain less well than men. A major review of pain studies found differences of over one-half a standard deviation for both pain threshold (the level at which a stimulus is perceived as painful) and pain tolerance (the level at which pain is no longer bearable).