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Most of us have experienced jealousy at some point. We know how to identify jealousy when it appears in us, and we can usually tell when someone else experiences jealousy, based on their actions.
But what exactly is jealousy?
In a traditional evolutionary psychology model, jealousy is an inherited response that once increased our chances of survival. Men, it has been argued, exhibit jealousy primarily in response to sexual threats to the relationship they are in. The alleged reason for this is that if our male ancestors could be sure that they were the actual fathers of the children they provided for, they were guaranteed to have their DNA passed on. Women, on the other hand, exhibit jealousy primarily in response to emotional threats to the relationship they are in. The alleged reason for this is that only females who had someone to provide food for their children had children that would survive, increasing the chance that their DNA would get passed on. This eventually gave rise to men with a sex-jealousy gene and women with an emotional-jealousy gene.
There are many problems with this description of jealousy: One is that it jealousy isn't equally pronounced in all cultures, which suggests that even if it does have a genetic root, it also has a strong social component. In other words, jealousy is partly cultivated.
As I have argued elsewhere, the evolutionary root of jealousy may not be sexual or emotional competition, but the endowment effect. This refers to our inherited tendency to assign greater economic value to something already in our possession than to something that we don't own. The endowment effect by itself does not fully explain jealousy. The further factor, which is cultural, is the tendency to consider our partner our sexual and emotional property, providing us with exclusive rights to sex and intimacy with them.
The latter explanation captures the evolutionary basis of jealousy, as well as the fact that its intensity and frequency can vary quite dramatically across cultures. What it shares with the traditional evolutionary account is the idea that jealousy is a response to the threat of losing one's partner or of not being the father of one's children. The idea that jealousy is a response to the threat of losing one's partner is likely the characterization that best fits most people's experiences of jealousy today.
But what sort of response is it?
One suggestion is that jealousy is a fear response to the threat of losing one's partner. But that cannot be quite right. If you know that your partner has terminal cancer, you may experience fear in response to the impending death. But you do not experience jealousy.
Another, better suggestion, is that jealousy is a fear response to the threat of losing one's partner to another person. But jealousy seems to involve more than just fear. Anecdotally, at least, people who experience jealousy often report experiencing sadness, disgust, and rage, among many other basic (or complex) emotions. Fear by itself does not automatically trigger this array of emotions.
Another plausible account of jealousy is that it involves fear of losing one's partner to another person, and resentment or indignation at the fact that the partner (and/or the sexual/emotional competitor) has put you into this insecure state. When sufficiently intense, this sort of response can trigger feelings of disgust, sadness, and/or rage.
One potential objection to this rough account of jealousy is that one can be jealous even when there is no actual threat to the relationship. Your partner may be jealous when you meet with an opposite-sex childhood friend, even though there is no chance that this friendship could ever develop into something more.
To deal with these cases, we need to distinguish between rational/appropriate and irrational/inappropriate instances of jealousy. You may experience fear, anger, indignation, disgust, and so on, even when there is no good reason for those emotions. Fear of flying is a case in point: It's irrational, at least for those who do not have a fear of driving, since it is far more likely that you will die in a car accident than in a plane accident. But it is not easy to shake a deeply-rooted fear. People sometimes go through many years of therapy to get rid of such phobias.
Jealousy, we can say, is irrational/inappropriate when there is no fear of losing a partner to someone else. There are, of course, instances when jealousy is inappropriate but nonetheless excusable because the jealous person has a good reason to believe that they may lose (or may have already lost) their partner to a sexual or emotional competitor.
There is at least one scenario that the proposed description of jealousy cannot account for: We often experience jealousy long after knowing that we have lost a romantic or sexual partner to another person. If we already know this, it doesn't make sense to say that our feeling of what appears to be jealousy is a fear of losing the partner. Further, our emotional reaction in these circumstances may be quite rational and appropriate.
I am tempted to think that the negative emotions experienced after a loss of one's partner to another person is not an instance of jealousy but something else. In some cases, it may be grief. In others, it may have to do with being treated unfairly. After all, your partner chose to love someone other than you, and that created a dramatic change in your reality.
Berit "Brit" Brogaard is the author of On Romantic Love.
