Forget Valentine’s Day: Can Love Be an Illusion?

 In GDI, Space, Environment

I am head over heels in love but my cyn­i­cal friends keep telling me that love is noth­ing but a cock­tail of pheromones, dopamine and oxy­tocin, and that these wear off after a couple of years. The thought scares me, it makes the whole thing seem mean­ing­less. Is love really just brain chem­istry? Jo, London.

Licence my roving hands, and let them go,

Before, behind, between, above, below.

It is no acci­dent that arguably the most erotic line of English poetry is all prepo­si­tions. The essence of love, at least of pas­sion­ate­ly roman­tic love, is revealed in its very gram­mar. We fall in love, not wander into it. And, as you say, we fall head over heels, not drag­ging our feet – often at first sight rather than on care­ful inspec­tion. We fall in love madly, blind to the other’s vices, not in ratio­nal appraisal of their virtues.

At its root, roman­tic love is spon­ta­neous, over­whelm­ing, irre­sistible, bal­lis­tic, even if, over time, its branch­es take on more com­plex hues. It is in con­trol of us more than we are ever in con­trol of it. In one sense a mys­tery, it is in anoth­er pure sim­plic­i­ty – its course, once engaged, pre­dictable and inevitable and its cul­tur­al expres­sion more or less uni­form across time and space. The impulse to think of it in terms of simple causes pre­cedes sci­ence. Consider the arrow of Cupid, the potion of a sor­cer­er – love seems ele­men­tal.

Yet love is not easily con­quered by sci­ence. Let us look at why. Sex pheromones, chem­i­cals designed to broad­cast repro­duc­tive avail­abil­i­ty to others, are often quoted as key instru­ments of attrac­tion. It is an appeal­ing idea. But while pheromones play an impor­tant role in insect com­mu­ni­ca­tion, there is very little evi­dence that they even exist in humans.


This arti­cle is part of Life’s Big Questions
The Conversation’s new series, co-pub­lished with BBC Future, seeks to answer our read­ers’ nag­ging ques­tions about life, love, death and the uni­verse. We work with pro­fes­sion­al researchers who have ded­i­cat­ed their lives to uncov­er­ing new per­spec­tives on the ques­tions that shape our lives.

If a chem­i­cal can signal attrac­tion out­side the body, why not inside it? The neu­ropep­tide oxy­tocin, often inac­cu­rate­ly described as a “bond­ing hor­mone” and known for its role in lac­ta­tion and uter­ine con­trac­tion, is the lead­ing can­di­date here. This has been exten­sive­ly stud­ied, mainly in the prairie vole, whose monogamy and public dis­plays of affec­tion make it an ideal model animal.

Blocking oxy­tocin dis­rupts the pair bond­ing that is here a sur­ro­gate for love, and makes the voles more restrained in their emo­tion­al expres­sions. Conversely, induc­ing an excess of oxy­tocin in other, non-monog­a­mous vole species blunts their taste for sexual adven­ture. In humans, though, the effects are much less dra­mat­ic – a subtle change in the roman­tic pref­er­ence for the famil­iar over the new. So oxy­tocin is far from proven to be essen­tial to love.

Of course, even if we could iden­ti­fy such a sub­stance, any mes­sage – chem­i­cal or oth­er­wise – needs a recip­i­ent. So where is the let­ter­box of love in the brain? And how is the iden­ti­ty of the “chosen one” con­veyed, given that no single mol­e­cule could pos­si­bly encode it?

When roman­tic love is exam­ined with imag­ing of the brain, the areas that “light up” over­lap with those sup­port­ing reward-seek­ing and goal-ori­ent­ed behav­iour. But that parts of our brains are set ablaze by one thing does not tell us much if they are just as excit­ed by a very dif­fer­ent, other thing. And the observed pat­terns of roman­tic love are not that dif­fer­ent from those of mater­nal bond­ing, or even from the love of one’s favourite foot­ball team. So we can only con­clude that neu­ro­science is yet to explain this “head over heels” emo­tion in neural terms.

Do we simply need more exper­i­ments? Yes, is usu­al­ly the scientist’s answer, but here that assumes love is simple enough to be cap­tured by a mech­a­nis­tic descrip­tion. And that is extreme­ly unlike­ly, as nature would resist it. Evolutionarily speak­ing, love is ulti­mate­ly about repro­duc­tion. Consider what would happen to an organ­ism whose sexual attrac­tion oper­at­ed through a very simple mech­a­nism involv­ing a string of crit­i­cal mol­e­cules, or a dozen or so vital neural nodes.

Its repro­duc­tive suc­cess would then be gated by the integri­ty of very few genet­ic ele­ments, with the poten­tial to be knocked out entire­ly by a muta­tion or two. A preda­tor could evolve a poison that ren­dered its victim not just com­pli­ant, but pos­i­tive­ly amorous, only too happy to slide from a petite mort to the real thing. Were some inan­i­mate thing to con­tain the key mol­e­cule in abun­dance, the entire species could become objec­tum sex­u­als, choos­ing to play with it over sex with each other. This is almost the joke truf­fles play on wild pigs, and it is telling that the ani­mals are only tem­porar­i­ly divert­ed by it.

But the evo­lu­tion­ary vul­ner­a­bil­i­ty goes deeper. Remember that sex is not pri­mar­i­ly about the repro­duc­tion of the species, but about its opti­mi­sa­tion, and not just in response to the world as it is now, but as it might be across the widest range of hypo­thet­i­cal futures. This requires that organ­isms are diverse across their traits, as much as select­ed for their fit­ness. Were it not so, a sudden change in the envi­ron­ment could make a species go extinct overnight.

So each repro­duc­tive deci­sion can be nei­ther simple nor uni­form, for we cannot be allowed to be guided by any single char­ac­ter­is­tic, let alone the same one. Universally attrac­tive though tall­ness might be, if biol­o­gy allowed us to select on height alone we would all have gigan­tism by now. And if the deci­sions have to be com­plex, so must the neural appa­ra­tus that makes them pos­si­ble.

While this explains why roman­tic attrac­tion must be com­plex, it doesn’t explain why it can feel so instinc­tu­al and spon­ta­neous – unlike the delib­er­a­tive mode we reserve for our most impor­tant deci­sions. Wouldn’t a cool, detached ratio­nal­i­ty be better? To see why it would not, con­sid­er what explic­it rea­son­ing is there for in the first place. Evolving later than our instincts, we need ratio­nal­i­ty only to detach our­selves from the grounds for a deci­sion so that others can record, under­stand and apply it inde­pen­dent­ly of us.

But there is no need for anyone else to under­stand the grounds for our love, indeed the last thing we want to do is pro­vide others with a recipe to steal our object of desire. Equally, in ceding con­trol to record­ed cul­tur­al prac­tice, evo­lu­tion would place too much “trust” in a capac­i­ty – col­lec­tive ratio­nal­i­ty – that is, in evo­lu­tion­ary terms, far too young.

It is also a mis­take to think of instinct as simple, and infe­ri­or to care­ful delib­er­a­tion. That it is tacit makes it poten­tial­ly more sophis­ti­cat­ed than ratio­nal analy­sis, for it brings into play a wider array of fac­tors than we could ever hold simul­ta­ne­ous­ly in our con­scious minds. The truth of this stares us in the face: think how much better we are at recog­nis­ing a face com­pared with describ­ing it. Why should the recog­ni­tion of love be any dif­fer­ent?

Ultimately, if the neural mech­a­nisms of love were simple, you should be able to induce it with an injec­tion, to extin­guish it with a scalpel while leav­ing every­thing else intact. The cold, hard logic of evo­lu­tion­ary biol­o­gy makes this impos­si­ble. Were love not com­pli­cat­ed, we would never have evolved in the first place.

That said, love – like all our thoughts, emo­tions and behav­iours – rests on phys­i­cal process­es in the brain, a very com­plex inter­play of them. But to say that love is “just” brain chem­istry is like saying Shakespeare is “just” words, Wagner “just” notes and Michelangelo “just” cal­ci­um car­bon­ate – it just misses the point. Like art, love is more than the sum of its parts.

So those of us lucky to expe­ri­ence its chaos should let our­selves be car­ried by the waves. And if we end up wrecked on the surf-hidden rocks, we can draw com­fort from know­ing reason would have got us no fur­ther.

To get all of life’s big answers, join the hun­dreds of thou­sands of people who value evi­dence-based news by sub­scrib­ing to our newslet­ter. You can send us your big ques­tions by email at [email pro­tect­ed] and we’ll try to get a researcher or expert on the case.

More Life’s Big Questions:

Parashkev Nachev, Professor of Neurology, UCL

This arti­cle is repub­lished from The Conversation under a Creative Commons license. Read the orig­i­nal arti­cle.

Image: Reuters

Source: National Interest

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