Previous research has shown that men are more likely to make utilitarian decisions than women, in the context of someone dying to save several lives. However, a recent study showed that men were more likely to make anti-utilitarian decisions if the person they were saving had greater reproductive value to them than those he sacrificed. Sexual rivals and women past reproductive age hold no reproductive value to men.

Researchers found evidence that men would choose to save the life of one possible reproductive partner rather than three people with no reproductive value, in a study published in Evolutionary Psychological Science. Consequently, scientists found that women would more consistently make utilitarian decisions to save the many over the one.

Scientists asked a question to their participants: “Given the choice, would you decide to cause the death of three members of your own sex, or to cause the death of one member of the opposite sex?” This question was asked in a variety of ways, through the use of four different scenarios — large city with a bank robbery, rural community running out of medicine, spaceship and oxygen consumption, and a remote island desperately needing food. However, researchers did not give the reverse scenario to the participants (cause the death of one member of your own sex or cause the deaths of three members of the opposite sex).

Sexual orientation was noted for only one scenario, which was the third study concerning the spaceship. Only homosexuals and heterosexuals were included in the results; those who identified as bisexual were excluded from the study.

About one third of women were willing to cause the death of three women rather than one man. For females, the younger participants were more likely to make anti-utilitarian decisions, which could be influenced by social norms.

“Although we observed a large and robust difference between the responses of men and women, the proportion of women making the hypothetical choice to kill three women rather than one man remained puzzlingly high, at about one third,” the researchers noted.

Age had no distinguishable effect on male participants’ decisions. Men were influenced by sexual competition and the age of the female to possibly be saved. Also, homosexual men were less likely to eliminate men, which supports the theory of sexual selection being an important influence on anti-utilitarian male decision making.

Researchers believe that this new information shows the “implicit value that male and female decision-makers put on male and female lives, in contexts going from healthcare to warfare.” The conclusion of this study is that male moral choices may reflect sexual selection and competition.

The researchers noted that social norms could influence men’s decisions.

“As captured by the ‘women and children first’ rule of escape, men may be socially expected to give priority to saving the life of women,” they noted.

However, that social norm fails to explain why men were no longer willing to sacrifice other men to save women past reproductive age.

“It is difficult to explain why a norm of chivalry would no longer apply to a woman older than 50, without appealing to additional ad hoc norms. An evolutionary account, though, easily explains why the life of a woman past her fertile years might be less of a priority for male participants,” they said.