other woman or leave their current relationship altogether. Either way, the female loses some of the male parental investment, and the loss of her mate's resources may significantly reduce the survival of herself and her offspring. The evolutionary psychology perspective has been supported by a study conducted by David Buss. He observed that male sexual jealousy is triggered by sexual infidelity, whereas female sexual jealousy is triggered by emotional infidelity. The study concluded that sexual jealousy may be an adaptive function that is triggered in order to retain access to a valuable mate. Researchers David Buss and Todd Shackleford propose and test several hypotheses about sexual jealousy: Men will devote more resources to mate retention when their partner is younger than them than men whose partner is older than them. This hypothesis rests on the evolutionary principle of mate value. Younger women are likely to have more mate value because they are more fertile. Therefore, it is predicted that men are likely to engage in mate retention behaviours more often when their partner is younger rather than older than them. Again based on the principle of mate value is the prediction that men will devote more resources to mate retention when their partner is perceived to be more physically attractive than when their partner is perceived to be less physically attractive. Females who are physically attractive have a higher mate value than those who are less physically attractive. Women will allocate more resources to mate retention when their partner has a wealth of resources than women whose partners have few resources. This hypothesis also rests on the mate value principle. Men who have more resources and wealth have a higher mate value than those who do not. If a man perceives his partner as having a higher mate value than him, then he is more likely to engage in efforts towards mate retention than men who perceive their partners as having a lower or equal mate value than them. This hypothesis rests on perceived mate value. If a male's partner has a higher mate value than him, she is more likely to be able to attract other men who may be of a similar mate value to her. As such, the male is at a greater risk of losing her to another man with a higher mate value. Individuals who suspect their partners are being unfaithful are more likely to