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Infidelity and Jealousy from an Evolutionary Perspective

When you feel as if someone poses a threat to your relationship (whether they do or not), jealousy likely creeps in. Researchers note that jealousy is characterized by fear of loss, distrust, or anger, as one is worried about losing a relationship due to a rival.1 Essentially, jealousy serves as a mechanism by which the person remains hypervigilant to protect his/her relationship from potential intruders. One common scenario which can elicit jealousy is when your partner is in the presence of available and datable others, resulting in the sense that a partner may be unfaithful.


In a previous article, I discussed theories of infidelity, focusing on the different perspectives offered by evolutionary psychologists and social-role theorists. The dispute between these two perspectives focuses on the difference in how distressed is measured. One approach is to use “forced choice” alternatives, which include answer choices in which a participant is to pick which is more upsetting from two pre-selected responses: your partner forming an emotional attachment with another individual (emotional infidelity) or your partner having sex with this other individual (sexual infidelity). Evolutionary psychologists have used this forced-choice paradigm to show that men are more upset by sexual infidelity, while women are more distressed by emotional infidelity.

From an evolutionary psychological perspective, the gender differences in outcomes resulting from an unfaithful partner, leads to different reactions to infidelity.1 Women fear that when a man has become emotionally involved with another, they (the women who have been cheated on) may lose some of the resources they have secured from their male partners. Men, however, fear that if their female partners are having sex outside of the relationship, the men are expending their resources on kin that potentially are not theirs. Basically both are weary of a circumstance in which their genetic offspring are not getting the resources needed. 

Not everyone agrees with the evolutionary perspective and instead feel that the gender differences are merely a result of the way in which the cheating scenarios are presented. Researchers in opposition to the evolutionary perspective note that gender differences disappear when participants can rate their views on a continuous scale.3 When forced to select an answer, people will choose the type (sexual or emotional) that co-occurs with the other.3 In relating this to the choice women make (emotional infidelity is more distressing), it is thought that a woman will assume that if her husband has fallen in love, he has already had sex with the other woman. Therefore, the selection encompasses both types of infidelity.

Infidelity and Jealousy

Extending the evolutionary perspective further, jealousy may have evolved as a result of the reproductive challenges (i.e., not having enough resources to provide for the child) that our ancestors faced and the issues that would arise if a partner is unfaithful.4 Men, in particular, have to struggle with paternity certainty, or the fact that they can’t be completely sure that the child a pregnant woman is carrying is his or another guy’s. Men would need to respond with jealousy if they suspected that their mate was about to stray, as this would decrease the likelihood that the woman would have sexual relations with another man.

Women, on the other hand, respond with jealousy when they suspect that the resources provided by their male partners, and reserved for their offspring, are being diverted elsewhere. Therefore, they would worry most when their mates develop emotional connections with others, as this signals the potential to re-allocate the resources to new women. 

What Does the Research Say?

One researcher conducted an experiment to examine the evolutionary perspective’s accuracy.4 In this study, the researcher manipulated the scenario (imagining your partner having sex or imagining your partner falling in love with someone else) and the race of the individuals (someone of the same or of a different race). If jealousy really arises from the need for the man to be certain of his paternity, sexual infidelity should be more threatening. Similarly, from the same perspective, women should find emotional infidelity more displeasing as it signals the re-allocation of necessary resources. The race of the person with whom the infidelity is committed should not influence the participants’ responses. However, if jealousy is a general emotional reaction to a potential threat to a relationship, then the race of the person with whom the partner is cheating may play a role. The researchers chose race as a variable to manipulate, as it is unrelated to any the sex specific threat of infidelity.

For this study, 286 students, 214 females and 72 males, from South Louisiana University were presented with scenarios regarding their imagined partner’s infidelity. Each participant was presented with four scenarios in which their partner was unfaithful, based upon the manipulations dealing with type of infidelity and race. Participants also rated, on six 7-point scales, how angry, jealous, calm, threatened, relieved and hurt they felt in response to each scenario.  Results demonstrated little effect of the influence of race of the partner with whom the infidelity occurred on reactions to imagined infidelity. The results partially supported the perspective that jealousy evolved for mate retention, because men were more angry and hurt than women in response to sexual rather than emotional infidelity. However, results were inconsistent with this in that they failed to show that women were more upset and hurt by emotional infidelity, compared to men. Overall, “women reported more anger over sexual than over emotional infidelity and were equally hurt by sexual and emotional infidelity.”3 Therefore, the idea that jealousy evolved specifically for mate retention is compelling, but does not account for all of the data.

Infidelity shakes the ground upon which the relationship is built, as it creates a violation of trust and breaks the commitment each partner made to one another. While this is clear, the theory best suited to explain our reactions to it is not. 

1Parrot, W.G. & Smith, R.H. (1993) Distinguishing the experiences of envy and jealousy. Journal of Personality and Social Psychology, 64, 906–920.

2Buss, D.M. (2000). The dangerous passion: Why jealousy is as necessary as love and sex. New York: Free Press.

3DeSteno, D. & Salovey, P. (1996). Evolutionary origins of sex differences in jealousy: Questioning the “fitness” of the model. Psychological Science, 7, 367-372.

4Bassett, J. F. (2005). Sex differences in jealousy in response to a partner's imagined sexual or emotional infidelity with a same or different race other. North American Journal of Psychology, 7(1), 71-84.

Dr. Marisa Cohen

Marisa, along with a colleague at St. Francis College, founded the Self-Awareness and Bonding Lab (SABL) in Fall 2014. Research has focused on the development of relationships throughout the life span, including factors influencing mate choice and peoples’ perceptions of what makes relationships survive and thrive. Her specific focus is on how various relationship configurations impact the satisfaction derived from them.

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