The discussion of appreciation is a novel and important feature of Kruglanski et al.’s (this issue) analysis. Although the mutuality of reciprocal affection has long been recognized as a decisive feature of romantic involvements, Kruglanski et al. elaborate this point nicely, including emphasizing the communicative aspect. It is not enough that the partner reciprocates one’s love or friendship: Ongoing or frequent expressions of appreciation for one’s good qualities help create and sustain the bond.

Although the importance of appreciation has also been recognized in other theoretical accounts of intimate human bonds (see, e.g., Huinink, Reference Huinink1995; Honneth, Reference Honneth1996; Windzio, Reference Windzio2024), Kruglanski et al. make a valuable and original contribution by embedding this aspect within a model of motivation. Their approach connects appreciation with merit and the actors’ quest for significance to explain the momentum of falling in or out of love.

In an evolutionary context, humans evolved to forage collaboratively, cooperating in hunting and gathering, including sharing information and, in some cases, agreeing to perform complementary roles in a hunt and share the prey. The elevated rate of cooperation in human social life was partly accomplished by establishing the importance of reputation (Chudeck & Henrich, Reference Chudek and Henrich2011; Henrich & Muthukrishna, Reference Henrich and Muthukrishna2021). The bigger and stronger hunter cannot hog all the proceeds of joint effort, as typically happens when other great apes are taught to cooperate (Tomasello, Reference Tomasello2016), because reputational damage would ensure that such a selfish, uncooperative person would soon run out of potential partners and would starve. Gossip, of course, helps circulate reputation-relevant information through the group, so betraying one partner will reduce the willingness of others to collaborate. Baumeister (Reference Baumeister2022) noted that most people have multiple concepts of self, but the most salient and important among them is the desired reputation. How one is regarded by others in one’s social group is much more pragmatically important than how one regards oneself. In that context, receiving appreciative messages from others can be deeply satisfying, because it affirms that one is being regarded the way one wants to be.

Kruglanski et al. say that “Perceived partner merit is subjective, though it is largely affected by social norms.” But social norms are not arbitrary and cannot be regarded as first causes. Indeed, the broad similarity of moral norms across the world is a sign that people everywhere favor the same sorts of behaviors in their fellows, mostly designed to enable constructive cooperation (Baumeister, Reference Baumeister2025; Curry, Reference Curry, Shackelford and Hansen2016; Curry, Mullins, & Whitehouse, Reference Curry, Mullins and Whitehouse2019). Even the few exceptions mainly conform to differences in cooperation. Schäfer, Haun, and Tomasello (Reference Schäfer, Haun and Tomasello2015) showed that children in societies that have not created economic marketplaces do not show concern with the kind of fairness that is required for such systems. Marketplaces are giant systems of cooperation, but the human psyche adapts to the socio-cultural environment that surrounds each of us, leading to (e.g.) variations in the adherence to norms (Markus & Kitayama, Reference Markus and Kitayama2010).

A particularly important form of cooperation involves co-parenting. Human males typically provide food, protection, and other benefits to both their offspring and the mother thereof, a pattern of behavior that is extremely rare if not entirely unknown among the other great apes. Passionate romantic love, extending over time, presumably evolved to facilitate this ongoing social bond, again unlike the other great apes. Expressions of appreciation are a powerful aspect of this process and bonding.

One of us did some research on unrequited love, indeed, as cited by Kruglanski et al. We wish to elaborate on the connection to their work. One source of unrequited love is what Baumeister and Wotman (Reference Baumeister and Wotman1992) called “falling upward,” that is, becoming enamored of someone whose mate value exceeds one’s own. (Not all romantic disappointments fit this formula, to be sure.) As covered by Kruglanski et al., people tend to be attracted to the most desirable potential partners they encounter – but broad patterns of assortative mating indicate that people mostly end up with partners who match them on key traits such as intelligence, social standing, and sex appeal. How does that happen? The situation is complicated by the fact that most people routinely overestimate their attractiveness. Using the colloquial 10-point attractiveness rating scale, we illustrate this with the example of a young man whose overall mate value is about 5, but he thinks he might be a 7. He approaches a young woman whom he regards as (“also”) a 7. Unfortunately, she perceives him accurately as a 5, while regarding herself as an 8 or 9. To him, they seem a perfect match, while to her, he is not worthy of consideration.

Appreciation is often a vital mediator of the process of getting from unrealistic attraction to assortative matching. When, despite their illusions, hopes, and inflated self-appraisals, people do enter into romance with someone who is a mutually suitable match, the bilateral appreciation can provide a crucial signal that the relationship has promise.