If there are phrases that characterize the life of our early ancestors, “community of sufferers” and “brotherhood of pain” surely must come close. Their lives were probably less labor-intensive than lives in modern society, as demonstrated by the !Kung, but the mortality rate would have been much higher. The advantages of group cooperation would include far more effective hunting and defense, and groups that failed to function cooperatively must have gradually died out. Adaptive behavior tends to be reinforced hormonally, emotionally, and culturally, and one can see all three types of adaptation at work in people who act on behalf of others.
Humans are so strongly wired to help one another—and enjoy such enormous social benefits from doing so—that people regularly risk their lives for complete strangers. That risk-taking tends to express itself in very different ways in men and in women. Men perform the vast majority of bystander rescues, and children, the elderly, and women are the most common recipients of them. Children are helped regardless of gender, as are the elderly, but women of reproductive age are twice as likely to be helped by a stranger than men are. Men have to wait, on average, until age seventy-five before they can expect the same kind of assistance in a life-threatening situation that women get their whole lives. Given the disproportionately high value of female reproduction to any society, risking male lives to save female lives makes enormous evolutionary sense. According to a study based on a century of records at the Carnegie Hero Fund Commission, male bystanders performed more than 90 percent of spontaneous rescues of strangers, and around one in five were killed in the attempt. (“Hero” is generally defined as risking your life to save non-kin from mortal danger. The resulting mortality rate is higher than for most US combat units.) Researchers theorize that greater upper-body strength and a predominantly male personality trait known as “impulsive sensation seeking” lead men to overwhelmingly dominate this form of extreme caretaking.
But women are more likely than men to display something called moral courage. The Righteous Among the Nations is an award given to non-Jews who helped save Jewish lives during the Holocaust and by its very nature selects for people who have a deep moral conviction about right and wrong. In Poland, the Netherlands, and France, providing refuge to Jews who were trying to evade the German authorities was a crime punishable by death, and while the decision to do so didn’t require the same kind of muscular action that men excel at, it could be just as deadly.
There are more than 20,000 names in the Righteous Among the Nations records, and an analysis conducted in 2004 found that if married couples are excluded, women slightly outnumber men in the list of people who risked their lives to help Jews. The greater empathic concern women demonstrate for others may lead them to take positions on moral or social issues that men are less likely to concern themselves with. Women tend to act heroically within their own moral universe, regardless of whether anyone else knows about it—donating more kidneys to nonrelatives than men do, for example. Men, on the other hand, are far more likely to risk their lives at a moment’s notice, and that reaction is particularly strong when others are watching, or when they are part of a group.
In late 2015, a bus in eastern Kenya was stopped by gunmen from an extremist group named Al-Shabaab that made a practice of massacring Christians as part of a terrorism campaign against the Western-aligned Kenyan government. The gunmen demanded that Muslim and Christian passengers separate themselves into two groups so that the Christians could be killed, but the Muslims—most of whom were women—refused to do it. They told the gunmen that they would all die together if necessary, but that the Christians would not be singled out for execution. The Shabaab eventually let everyone go.