Evolution of Sex-Based Differences in Jealousy

This entry was written by Shaniah Elliott as part of a project done in BIAN 6133 ‘Human Reproductive
Strategies’ at The Australian National University in 2019 Semester 2.”


The study of human emotions is a complex mainstream conducted by various types of researchers, most commonly psychologists and physiologists. A major issue with these researchers however, is their lack of studying emotions from an evolutionary perspective (Ramachandran & Jalal, 2017). The evolutionary perspective on emotions posits that they are adaptive responses to the changing environment that increase the organism’s chance of survival. The popular ruling of human emotions is that they are both biologically and socially influenced, depending on the emotion felt (Ramachandran & Jalal, 2017). Perhaps the most illustrious emotion among evolutionary psychologist research is jealousy, and in particular, sexual jealousy, which has been noted as an innate module that has evolved differently in men and women (Harris, 2003).

This entry will examine the evolutionary psychology behind sex-based differences in jealousy and the various factors that led to its creation in our ancestors. This entry will also analyse the various studies conducted to demonstrate the distinct difference between men and women, as well as differences in sexual orientation.

Main Text

The Evolutionary Perspective of Jealousy

The specific innate module created by evolutionary psychologists argues that in the case of sexual jealousy in humans, men are innately predisposed to react to a mate’s sexual infidelity while females are innately predisposed to react to a mate’s emotional infidelity (Buss et al., 1992). In today’s society, these wired emotions may not necessarily contribute to increasing one’s fitness, but in the Pleistocene period, they did (Harris, 2003). By studying fossil records and our closest relatives, chimpanzees, a potential prediction of our Australopithecine ancestors can be made. It is assumed that they were a polygynous society, in which one male mated with multiple females. This type of society has no need for sexual jealously, as often times, no emotional connection is made between the two mates, and the male is only attempting to increase his fitness. The Pleistocene period however, marked the onset of the last ice age as well as the evolution of Homo. With this change of environment into harsher conditions, hominid infants required prolonged dependency as well as more parental investment (Harris, 2003). An infant’s survival was predicted to be low if no male investment occurred during this unforgiving period, hence it is predicted that a pair-bonding system within social groups emerged during this time (Harris, 2003).

It is predicted by evolutionary psychologists that with the formation of pair-bonding systems also came the creation of jealousy. The sex differences noted in the expression of jealousy are thought to be influenced by our ancestors’ hunter-gatherer societies (Harris, 2003). The division of labour in hunter-gatherer societies was based on sex, with females acting as the gatherers and staying near base camp, and males acting as the hunters, often leaving camp for days. The chronic separation between two pair-bonded mates, resulted in the potential for infidelity, especially by the female. This sexual infidelity by the female could result in to her pair-bonded male investing in an offspring that is not his, thus making him more likely to react with jealousy (Sargarin et al., 2003). However, if the male was to commit infidelity, the female is likely to lose her pair-bond with him as well as risk the offspring’s survival; therefore, she is more likely to react with jealousy to her partner’s emotional infidelity as it means he is investing in another female (Sargarin et al., 2003). Overall, the aim for both pair-bonded organisms is to increase their fitness; to males this is often by guaranteeing the offspring is his, while to females it is guaranteeing offspring survival through resources commonly obtained through the paternal figure (Sargarin et al., 2003). If either of these understandings are disturbed, the potential for jealousy arises.

Establishing the Sex Based Differences of Jealousy

The evolutionary explanation of jealousy, in which men are more likely to respond to their female partner’s sexual infidelity while females are more likely to respond to their male partner’s emotional infidelity, is supported by various studies (Buss & Hasselton, 2005). In an experimental study conducted by Buss et al. (1992), undergraduate students were presented with two scenarios, one in which their partner committed emotional infidelity and one in which their partner committed sexual infidelity. This study also asked follow up questions to each scenario which involved participants imagining their partner trying different sexual positions for sexual infidelity, or falling in love with the other mate for emotional infidelity. The results supported the evolutionary perspective as males showed greater distress to sexual infidelity while females showed greater distress to emotional infidelity. The Buss et al. (1992) study didn’t just support the evolutionary perspective of jealousy, it also demonstrated how a person physiologically responds to a partner’s infidelity. Physiological responses of jealousy were recorded through the analysis of each participant’s pulse rate as well as their facial expression via the electrodermal activity of the brow ridge. The participants were asked to imagine the two scenarios from the first part of the study and their physiological activity was recorded. The experiment showed that in the jealous response to infidelity, a person will often experience an increase in heart rate as well as a greater unpleasant emotional response in their facial features. A cross cultural comparison conducted by Buunk et al. (1996), which involved Germany, the Netherlands and the United States, concluded the same results as the Buss et al. (1992) study.

The Reproductive Threat-Based Model of Jealousy

The evolutionary explanation for the innate model of sex differences in jealousy is based on a male’s risk of paternal uncertainty and a female’s risk of losing resources for her offspring. This model, however, is based off the answers provided by heterosexual individuals in scenarios where they are imagining their partner is committing infidelity with a mate of the opposite sex. A study similar to the Buss et al. (1992) experiment was conducted by Sargarin et al. (2003), which analysed the distress response of heterosexual individuals who imagined their partner committing either sexual or emotional infidelity with either a member of the same or opposite sex. The study concluded that in the light of same sex infidelity, participants experienced less jealousy-based distress, and in particular, men who imagined their female partner committing infidelity with another female. It is suggested that this reaction occurs because the fitness implications such as paternal skew, are significantly different than if the infidelity were with a member of the opposite sex (Sangarin et al. 2003 & Sangarin et al. 2012). From an evolutionary perspective, these results are proposed to have arisen via evolutionary adaptiveness in which non-exclusive same sex behaviour was a common occurrence in our ancestral societies (Sangarin et al. 2012). This can be explained by one of our closest relative, the bonobo, who uses same sex sexual interactions to diffuse tension in their social groups (Sangarin et al., 2012). The Sangarin et al. (2003) study ruled that in the case of heterosexual mates, a reproductive threat-based model has evolved and led to the sex differences in jealousy.

The Case in Which Sexes Do Not Differ

The evolution of sex-based jealousy is heavily linked to the reproductive threat-based model in which the fitness of an individual is at risk if their partner chooses to commit infidelity. This sex-based difference, however, can disappear in the case of homosexual individuals. Several studies (Harris, 2002 & Sangarin et al., 2012) have experimented on the distress a homosexual individual may experience if their partner were to commit either sexual or emotional infidelity and whether the sex of the other mate contributed to their reaction. These studies (Harris, 2002 & Sangarin et al., 2012) found little difference in reactions from lesbians and gay men, with responses indicating that any form of infidelity caused jealousy-based distress. This response contradicts the reproductive threat-based model, in which it would be predicted that due to homosexual individuals facing no threats to potential offspring survival or certainty, no jealous behaviour would be noticed in the case of infidelity.


The sex-based differences that occur in the human emotion of jealousy are explainable theories in the light of evolutionary psychologists who have provided numerous studies that demonstrate how individuals respond to emotional and sexual infidelity. The predisposed reactions by both men and women are feedbacks that have evolved over time and are produced in response to the potential risk of paternal uncertainty or loss of paternal investment. The evolutionary perspective provides understanding to the actions caused by jealousy; however, it should not be noted as its only influencer. Human emotions are a complex circuit board that can be influenced by outside factors and unknown stimuli as seen in the case of homosexuality, where no threat-based accounts on potential offspring occur.

Literature Cited

Buss, D.M., & Haselton, M. (2005). The evolution of jealousy. Trends in Cognitive Sciences, 9(11), 506-507.

Buss, D.M., Larsen, R.J., Western, D., & Semmelworth, J. (1992). Sex differences in jealousy: Evolution, physiology and psychology. Psychological Science, 3(4), 251-255.

Buunk, B.P., Angleitner, A., Oubaid, V., & Buss, D.M. (1996). Sex differences in jealousy in evolutionary and cultural perspective. Psychological Science, 7(4), 359-363.

Harris, C.R. (2002). Sexual and romantic jealousy in heterosexual and homosexual adults. Psychological Science, 13(1), 7-12.

Harris, C.R. (2003). A review of sex differences in sexual jealousy, including self-report data, psychophysiological responses, interpersonal violence, and morbid jealousy. Personality & Social Psychology Review, 7(2), 102-128.

Ramachandran, V.S., & Jalal, B. (2017). The evolutionary psychology of envy and jealousy. Frontiers in Psychology, 8, 1-7 (article 1619).

Sagarin, B.J., Vaughn Becker, D., Guadagno, R.E., Wilkinson, W.W., & Nicastle, L.D. (2012). A reproductive threat-based model of evolved sex differences in jealousy. Evolutionary Psychology, 10(3), 487-503.

Sagarin, B.J., Vaughn Becker, D., Guadagno, R.E., Wilkinson, W.W., Nicastle, L.D, & Millevoi, A. (2003). Sex differences (and similarities) in jealousy: The moderating influence of infidelity experience and sexual orientation of the infidelity. Evolution and Human Behavior, 24, 17-23.

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License