A new study shows men are more jealous of sexual infidelity, while women are more jealous of emotional infidelity.
Researchers at the Norwegian University of Science and Technology (NTNU) say evolutionary psychology may help explain the difference.
“Men and women’s psychology is similar in most areas, but not when it comes to reproduction,” said Associate Professor Mons Bendixen from the university’s Department of Psychology.
He teamed with NTNU Professor Leif Edward Ottesen Kennair and Professor David Buss at the University of Texas, Austin, for the study, which involved more than 1,000 participants.
Although the evolutionary psychologists expected women and men to respond differently to questions about infidelity and jealousy, they report they were surprised the differences were so strong.
That’s because Norway is known for its culture of gender equality. Fathers are expected to be there for their children, from changing diapers to child care. Norwegian paternity leave and other laws send the message that men should invest time in their families.
At the same time, support for single parents makes it possible to raise children alone if dads don’t pull their weight.
And yet, even in that culture of gender equality, large differences persist in what triggers jealousy in men and women, the researchers noted.
Recent research on jealousy considers two main types of infidelity: Having sex with a person outside the relationship, or developing an emotional attachment to a person outside the relationship.
Psychology has two contrasting theoretical perspectives on men and women’s emotional responses to infidelity. The first has its roots in cultural gender roles, while the other takes an evolutionary psychology perspective, the researchers explain in their study, which was published in the journal Personality and Individual Differences.
The first perspective maintains that in a culture with a high degree of equality, men and women interpret the world similarly. According to this approach, the human mind is largely shaped by the different roles that cultures assign to women and men and the experiences they have in those roles.
The evolutionary perspective is different, the researchers note. It contends that over thousands of generations men and women have had to adapt to different challenges that are related to reproduction, including infidelity.
A man must decide whether he really is the father of his partner’s child, and if he should choose to invest all his protection and resources on this child.
According to evolutionary psychology, men’s jealousy is an emotional reaction to signs of sexual infidelity. The jealousy serves to reduce the chances that his partner is cheating, since he then monitors her more closely.
It’s a different story for the mother. She knows for sure that she is the child’s mother, but she must ensure that the child’s father will provide their offspring with food and the security and social status it needs. The greatest threat for the woman is not that the man has sex with other women, but that he spends time and resources on women other than her, the researchers explain.
That’s why evolutionary psychologists believe women are especially sensitive to signs that the man is devoting time and attention to other women.
According to Bendixen, women who were indifferent to whether a man was emotionally attached to other women were more likely to have to take care of the child without his resources. Men who were indifferent to whether the woman had sex with others and who therefore invested resources on other men’s children, ended up passing on fewer of their genes.
“We are descendants of men and women who have responded appropriately to these threats,” he said.
He adds that neither past experiences with infidelity nor whether we are in a relationship seem to affect men’s and women’s reactions to infidelity.
“The cultural gender role perspective believes that jealousy is learned, but we feel confident that these reactions are mechanisms that are part of an evolved human mind, given comparable findings across several nations,” he explained.
In the new study, participants were randomly given one of four versions of a questionnaire about jealousy. Half the respondents were asked to check off whether the emotional or sexual aspect of infidelity was the most upsetting to them in four different infidelity scenarios, a so-called “forced choice” paradigm.
The other half rated the scenarios using a continuous measure. They were asked to report on a scale from one (not at all) to seven (very) how jealous or upset they were when the scenarios described either emotional or sexual infidelity.
In addition, the order of the questions was changed in half of the forms, so some people were asked about their experiences with infidelity before they answered the scenario questions. The remaining participants answered these questions after the scenario questions. This manipulation turned out to have no effect on how participants responded, the researchers reported.
“As in two of our previous studies, we found clear sex differences in the jealousy responses among those who had to choose which aspect of infidelity was most upsetting to them,” Bendixen said.
“We also found similar sex differences when we used a continuous measure paradigm. These sex differences are remarkable, since they were obtained using two alternative methods of measurement, and in a highly egalitarian nation with high paternal investment expectancy.”
Photo Credit: NTNU