Know more about jealousy

Most people have experienced jealousy at some point in their life. We usually know how to identify the emotion when it appears in ourselves, and we are fairly good at telling when others experience jealousy on the basis of their actions. But what exactly is jealousy?

On a traditional model in evolutionary psychology, 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 relationships they are in. The reason for this supposedly is that only those of our male ancestors who were the actual father of the children they provided for were guaranteed to have their DNA passed on. Women, on the other hand, exhibit jealousy primarily in response to emotional threats to the relationships they are in. The reason for this allegedly is that only those of our female ancestors who had someone to provide the 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 account 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. The endowment effect is 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 partners our sexual and emotional property, providing us with exclusive rights to sex and intimacy with them.

This latter explanation captures the evolutionary basis of jealousy as well as the fact that its intensity and frequency can vary quite dramatically across culture. What it shares in common with the traditional evolutionary account is the idea that jealousy is a response either to the threat of losing one’s partner or 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 vast array of emotions.

Another plausible account of jealousy is that it involves fear of losing one’s partner to another person, and resentment of 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 e.g. 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. A partner may be jealous when you meet with your childhood friend, even though there is no chance that your friendship could ever develop into something more (maybe you grew up together and consider each other siblings of sorts).