Sex Differences in Jealousy: A New Paper Analyzing a Boatload of DataPublished 21 May, 2012
A new paper by Brad Sagarin and colleagues in press in Evolution and Human Behavior addresses a roiling debate among researchers studying jealousy. Sagarin et al. harvested 209 effect sizes from studies investigating jealousy using various techniques to assess whether there is, as some have proposed, a sex difference in jealousy, as well as a number of additional issues swirling around this issue. In case you don’t want to read any further, the answers are: 1) yes, there’s a sex difference as predicted by parental investment theory, 2) no, this difference doesn’t appear only on forced-choice question formats, and 3) no, the difference is not limited to hypothetical infidelities.
Readers of this blog are likely to be familiar with the arguments surrounding jealously from an evolutionary point of view. (If not, don’t be shy about getting a copy David Buss’ book on the topic.) Briefly, the adaptive problem that men face to a greater extent than women in paternity uncertainty. To defend against the possibility that a man’s mate has sex with another man, jealousy, on this account, is designed to deter sexual contact. So men, more than women, should be expected to be more sensitive to, and react more strongly to, the possibility of sexual infidelity in order to implement this deterrence function. By contrast, women face a greater problem of the diversion of investment. To deter a man diverting resources to another woman, the argument goes, women should be expected to be more sensitive to and react more strongly to cues associated with the diversion of resources.
A number of researchers have taken issue with this line of argument, and proposed alternative accounts. For example, DeSteno et al (2006) published a paper in the Journal of Personality and Social Psychology in which they suggested that “little empirical evidence exists that provides strong support for a specific model of jealousy,” and that “the previously prevailing view that jealousy stems from sex-specific, evolved modules sensitive to reproductive threats (see Buss et al., 1992) has encountered formidable theoretical and empirical difficulties that limit its viability.” (I’m not in a position to judge the former claim, since I’m not sure how much evidence would count as more than just a little; as for the theoretical and empirical difficulties, I (and my colleagues) are skeptical of the sort of arguments that DeSteno and his colleagues level against the evolutionary account.)
In any case, presumably in part because of their worry about this supposed viability limit, DeSteno et al. propose an alternative perspective, locating the issue not in the threat to paternity certainty or parental investment, but in a perennially favored “explanation” in social psychology, self esteem, writing (citations omitted):
…it is our contention that threatened self-esteem is the principal mediating mechanism of jealousy…Our central point is that the appraisal centers on the self-system, and variations in momentary levels of self-esteem stand as the driving force for jealousy (p. 628)
With respect to jealousy, the role played by self-evaluation may be quite specific. Given that the attention one receives from a partner in a valued relationship is usually taken to signify self-worth, a partner’s interest in a rival stands as a signal that the rival is superior in some way to the self, and, consequently, the integrity of the present relationship may be threatened by the value the partner places on the rival… (p. 628) Put simply, maximizing self-esteem derived from the views of relationship partners safeguards the more tangible resources stemming from these relationships (p. 629).
I’ve written elsewhere about my views on theories that point to the “desire to feel good about the self” as a psychological explanation, and I won’t belabor the point here, except to say that I am actually fairly confident that self-esteem as the key explanatory variable for understanding jealousy will do about as well as it has in other contexts. (On the other hand, this idea does help to explain why men so frequently tell their romantic partners, sure, go ahead and have sex with him, just as long as you don’t place more value on him than me…)
In any case, Sagarin et al. address two critiques raised in the context of the jealously literature. The first surrounds measurement, with the claim being that the sex difference – men showing more jealously to sexual infidelity compared to women – occurs in forced choice methods (i.e., indicate which would make you more jealous, sexual or emotional infidelity) but not continuous methods. The second critique is a worry that the sex difference appears in hypothetical dilemmas (i.e., in such a case, how would you feel?) as opposed to actual cases.
Sagarin et al. spend some room in the paper laying out what predictions the evolutionary argument makes, and although this material is worth a careful read, I won’t review it here. Briefly, they argue that the key issue is the interaction term, that men should show a bigger difference than women show in their responding to sexual versus emotional infidelity. They also have a nice discussion of how one ought to treat Likert scale data, and I like one passage in the paper on this topic (p. 5):
[I]f we are unwilling to make any assumptions about response scales that go beyond ordinality, nearly every parametric test performed on nearly every response scale used in psychological research is essentially uninterpretable. This would include vast quantities of psychological research, including all attitudes research that used Likert and semantic differential scales, all personality research that used standard response scales to measure self-esteem, the Big 5, self monitoring, and other individual difference constructs, all emotion research that used the Positive and Negative Affect Scale (PANAS) and similar instruments to assess affect, and so on. This seems to be a lot to sacrifice at the altar of a measurement taxonomy.
The main contribution of the paper, however, is the meta-analysis, which consisted of analyzing 199 effect sizes drawn from 47 independent samples. Summarizing their findings regarding the key issue of continuous measures, they write: “One of the clearest findings in the meta-analyses is the existence of a sex difference in negative emotional responses to hypothetical infidelity scenarios using continuous measures” (p. 15). In terms of the issue of actual versus hypothetical infidelity, there are, as one might expect given the methodological challenges, fewer studies that investigate actual infidelity but, still, Sagarin et al. write:
Across the seven independent samples that measured responses to actual infidelity experiences, a significant, theory-supportive effect emerged (g*=0.234, 95% CI [0.020, 0.448], p=.03) with three individual effects statistically significant, all in the theory-supportive direction. Moreover, from a statistical perspective, the data yielded by these studies is not substantially different from the data yielded by the studies that have assessed jealousy responses to hypothetical scenarios, lending credence to the results that have emerged from both types of studies.
An additional result of their analysis is that it matters a great deal which emotion researchers ask subjects about. As one might expect, the effects are strongest when subjects indicate their level of jealousy, while for other emotions – anger, disgust – the effects are smaller. They conclude that “the choice of emotion measured helps to explain the diversity of past findings, with studies that measured distress/upset and jealousy producing significantly larger effects than studies that measured other emotions” (p. 15).
Sagarin et al also looked at variables that moderate these effects, and identify a small number of them, including the use of student samples and some methodological choices, such as whether the study was conducted on a computer.
The controversy surrounding jealousy is unlikely to be settled by the present paper, but by brining together the large number of studies in this way, Sagarin et al have provided an important analysis that researchers in this area will have to address as different models of jealousy are evaluated.
Buss, D. M. (2000). The dangerous passion: Why jealousy is as necessary as love and sex. New York: Free Press.
DeSteno, D., Valdesolo, P., & Bartlett, M. Y. (2006). Jealousy and the threatened self: Getting to the heart of the green-eyed monster. Journal of Personality and Social Psychology, 91, 626–641.
Postscript: People sometimes ask me about the turnaround time at Evolution and Human Behavior. This paper was submitted on January 5th, underwent one round of revisions, was accepted on February 28th, and published online on the 11th of May. This speed is not necessarily typical, but the editors at E&HB are very conscious of the issue of turnaround time, especially between submission and initial decision.