When Love Feels at Risk: The Hidden Logic of Jealousy
– by Ana María Fernandez, María Barbato, Michele Dufey
Jealousy is often portrayed as irrational, possessive, or simply unpleasant. Yet from an evolutionary and developmental perspective, jealousy may be better understood as a socially intelligent alarm system: an emotion that becomes activated when a valued relationship appears to be threatened by a third party. In our study, we tried to “switch on” this alarm in a controlled way, by presenting concrete decisions about how partners distribute resources between their romantic relationship and a potential rival.
This alarm system does not begin in adulthood. It can be observed early in life, when infants protest the apparent loss of a caregiver’s attention to a sibling or another person. Later, in friendships, jealousy may emerge when a newcomer threatens to replace our special place in a best friend’s affection.
Romantic jealousy follows a related logic; it is commonly understood as a response to threats of sexual or emotional infidelity. But beneath these familiar scenarios lies a broader question: what exactly is being protected? From an evolutionary perspective, romantic jealousy may function to protect exclusive access to a partner’s affection, attention, time, commitment, and investment. It is not only about sex, but about the possibility that a partner’s valued resources—emotional, social, reproductive, or material—may be redirected toward a rival.
This broader view motivated our research. For many years, studies of romantic jealousy relied heavily on hypothetical forced-choice scenarios, especially those contrasting sexual and emotional infidelity. We wanted to move beyond asking people to imagine betrayal in the abstract. Instead, we sought to create a more interactive experimental situation in which jealousy could be evoked through the allocation of resources. The economic game we used was designed to capture exactly this sense of being chosen, how much “goes to me” versus “goes to someone else” becomes a simple but powerful signal of where a partner’s attention and commitment are directed.
So, we invited romantic couples to the laboratory and used a modified economic game inspired by the dictator game. Participants were led to believe that their partners had exchanged resources with anonymous opposite-sex individuals. The game allowed us to model two different kinds of rival-related threats.
In the first condition, which we will call emotional investment, participants were informed that their partner had given most of their available resources—75 out of 100 dollars—to an opposite-sex person they had just met, rather than to the participant. This situation was designed to represent a partner actively directing resources toward a potential rival, and evoked the highest jealousy overall, and it was stronger among women than men.
In the second condition, which we will call mate poaching, participants were told that an opposite-sex person, already in a relationship, had given most of their resources to the participant’s partner, at the expense of their own partner. This was designed to represent someone else attempting to invest in, attract, or “poach” the participant’s partner, and it tended to evoke more jealousy among men than women, although the effect was weaker than expected
Importantly, we also included control conditions. These allowed us to examine whether participants were simply reacting negatively to any unequal allocation involving the opposite sex. The answer was no. Jealousy was not merely a response to unfairness, generosity, or discomfort with resource exchange. Rather, jealousy was especially heightened when the allocation implied a possible shift in relational investment: when a loved one appeared to give more to someone else than to the participant.
This is the central novelty of the study. Romantic jealousy may be triggered not only by explicit sexual or emotional betrayal, but also by subtle signs that a partner’s investment is being redirected. A simple economic decision—who receives more, who gives more, and at whose expense—can carry relational meaning. It may signal closeness, preference, availability, or threat.
Why does this matter? Because jealousy is often studied as if it belongs only to adult romantic life. Our findings suggest that jealousy may be part of a broader relational system that develops across the lifespan. From infancy to friendship to romantic love, jealousy appears when a valued bond feels vulnerable to displacement. It protects not only mating interests, but also attachment, exclusivity, affection, and the expectation that we hold a special place in another person’s mind.
By using an economic game, our study offers a new way to examine jealousy experimentally. It also helps refine the evolutionary interpretation of jealousy. Going beyond basing jealousy on sex differences or infidelity scenarios, the findings point to a more general mechanism: jealousy is activated when the exclusive investment of a significant other appears to be at risk. Jealousy-related feelings should also be placed in a constructive relational perspective. They do not reflect conflict or insecurity alone; they may also signal that closeness, attention, and commitment matter, and motivate healthy ways to protect them.
The green-eyed monster, then, may not be merely a destructive force. It can also be seen as an evolved emotional signal, alerting us when a valued bond feels less secure, less exclusive, or less reciprocally invested than we expected. In this sense, jealousy reveals something deeply human: our need not only to love, but also to feel chosen, valued, and uniquely held in the mind of another. When understood constructively, jealousy may become less a threat to relationships than an invitation to reflect on what our closest bonds require to remain secure, reciprocal, and meaningful.
