Mind Design

Yeah, there's an adaptation for that...

Why Love?

One of evolution's cruelest gifts

The things we do for love...

Love is on my mind because on Tuesday my lecture in class was about the evolved function of emotions, and I focused on a few in particular, including love.

To motivate the discussion, I began by trying to persuade my students that, many-splendored thing it might be, love presents something a puzzle. Consider some apparently epically poor decisions from literature. Paris might be forgiven for falling for Helen, but was his next best option so much worse that it was worth starting a war? Could Lancelot and Guinevere not put their love aside, set against their loyalties to Arthur, King and husband? And when Romeo and Juliet believed the other to be dead, was suicide preferable to searching for another, though doubtless less compelling, mate?

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While the fitness consequences of such decisions seem to speak for themselves, those who have fallen in love might be inclined toward not just answering each of these with a yes, but shouting its obvious truth with ebullient, confident enthusiasm. Who among us with the least poetry in our souls has not felt the unanswerably sublime pull of another, whose virtues so ensorcel that we feel as though we might fight, kill and, yes, die that we might be together?

And so, an evolutionary puzzle. If emotions function to guide us toward adaptive behavior, not the least of which entails making good tradeoffs in decision-making, what is this thing called love, and why does it torment us so? No one seems immune, as even the rich and powerful seem ready to make sacrifices at the altar of love, as cases from Edward VIII to John Edwards illustrate. We all dance to love’s tune and obey the pull of her strings.

In class I focus on Robert Frank’s answer to this question, presented in Passions Within Reason. Briefly, Frank views love as a commitment device. Partners in budding romances want to know that their beau will not leave them. Love, Frank argues, causes people to feel irrational affection for another, in turn motivating behavior that signals these feelings and, so, commitment. If Romeo can persuade Juliet that he will not leave her even when a mate with better properties comes along, then Romeo is better off doing just that to the extent that Juliet is swayed by evidence of his steadfastness.

Critics have worried about Frank’s answer. As a commitment device, love relies on signaling, and it’s not always clear that the sorts of signals love broadcasts are honest, in the technical, not lay, sense of the term. Protestations of ardor, perhaps especially in verse, are all to the good, but nothing in poetry’s dulcet voice prevents abandonment in life’s shadowy future. When Romeo avers that his heart never lov’d till this night, why should Juliet be swayed? Flowery verse, even set to iambic pentameter, succumbs to the economist’s charge of cheapness. Is it not as easy to leave a relationship that began with literary flights on Cupid’s wings as one that did not?

For Frank, the answer is that one simply can’t, as a psychological matter, show these symptoms of love unless one is genuinely in love, making the symptoms a reliable cue to the affliction. Though I confess to being somewhat skeptical of such arguments in principle, I sympathize deeply with the intuition. Scenes in the film Shakespeare in Love, in which the Bard pens purple prose – inspir’d by fair Viola – ring true to the viewer, as if only the muse of true passion could evoke such sentiments. If love’s lines come only of love, then do the words born of love’s muse not have some power to predict?

Poetry is not, of course, the only one of love’s products. In class I also discuss Dorothy Tennov’s notion of “limerence,” the intense feelings experienced when one finds oneself irretrievably and irrevocably in love. Tennov usefully catalogs some peculiarities of limerence, not the least of which is that people experiencing it seem, more or less, incapable of attending to anything else. As Tennov renders it, the object of one’s love dominate one’s thoughts, intruding into, and interfering with, all other aspects of life, resembling a kind of addiction, as the lover craves the loved. Further, people experiencing limerence spend inordinate amount of time dissecting their would-be lover’s words and deeds for signs that their feelings are, or are not, reciprocated. Tennov also suggests that limerence causes a certain amount of failure to engage with reality, seeing hope for the possibility of a relationship where a more dispassionate appraisal would suggest there is little, or none.

A woman to die for...?

All these symptoms might persuade a potential mate of the depths of one’s feelings, but, if all of this is right, then being in love imposes some serious costs. The obsessions of love seems to radically tilt tradeoffs toward the pursuit of the target of one’s affection and away from nearly everything else. Certainly an argument can be made about the importance of pursuing a mate, but the symptoms of limerence, and the sorts of (fictional, true) examples above make it look as though love pushes us, at least on occasion, too far.

Further, some might argue that Frank’s argument suffers to the extent that it’s right. That is, suppose love does, in fact, cause someone to stay with their current mate even when a better option comes along. If love has this effect on decision making, then the benefits of signaling commitment would have to be relatively large to offset these potential costs.  Still, to the extent feelings of love genuinely foreclose alternative options in the service of signaling commitment, a potentially treacherous tradeoff is being made. The details, of course, ought to matter. How likely is a better alternative to come along? If one does, how much better is the alternative likely to be? Love’s loyalty makes the most sense in a world in which the next best option is only marginally better than the status quo. Does love look so peculiar to us in part because of the modern world’s greater vocabulary of possible lovers? In ancestral environments, if the variance were lower, then commitment might have constituted a potentially less costly tradeoff.

To end by returning to arguably the most famous love story of all time, what are we to make of the impact of the detritus of love denied, when happily ever after eludes us? That is, if love is a commitment device, when love passes out of reach, why does it persist and torment – causing both Romeo and Juliet to endure the greatest of all fitness costs –  rather than gracefully simply fading away? The agony of unrequited love, so paralyzingly horrible, seems absurdly counterproductive, in addition to, from the point of view of the unsuccessful suitor, transcendentally painful. As an adaptive matter, it would seem that the right response to doomed courtship is resuming the search; the worst response is lover’s leap, the course favored by so many. Even those who have resisted paying the ultimate price when their favored mate proves out of reach, the aftermath of rejection seems to pose enormous costs in the form of withdrawal from life’s other pursuits. The dejection of the spurned appears as painful as it is unproductive. If there is a crueler burden with which we have been saddled by evolution than the agony of a broken heart, it is hard to imagine what it might be.

This is a repost of an entry that appeared on my other blog: http://www.epjournal.net/blog/2013/02/love/. 

Copyright Robert Kurzban. All Rights Reserved. 

Robert Kurzban, Ph.D., is an Associate Professor at the University of Pennsylvania and the author of Why Everyone (Else) Is A Hypocrite.

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