As you cuddle with your mate your brain receives a comforting surge of oxytocin, reinforcing your feelings of attachment. More intimacy gives your pleasure centers a shot of dopamine, strongly reinforcing the behavior. Your brain becomes increasingly bathed in dopamine, serotonin, and other hormones and  neurotransmitters, resulting in a suite of physiological and behavioral responses evolved to maximize the probability of inserting your genes into the next generation.

In the afterglow of your subconsciously Darwinian act, you contemplate what attracted you to your mate in the first place. If you are male then you probably responded positively to a certain waist to hip ratio indicating good birthing potential. Full lips and facial features with a rosy tone to the skin also indicates youth and health – other good predictors of of breeding success.  Females are also attracted to signs of health and vigor, but also dominance and power (however this specifically manifests in your culture).

Evolutionary changes to your brain’s hardwiring and chemistry have spared you the tedious task of performing a biological assessment of potential mates. Rather, you just have an automatic feeling – an attraction – that is largely based upon a cold subconscious calculus of breeding and life success. You find yourself thinking obsessively about a good mating prospect. You may feel giddy just by being in their presence. The mere sight of them gives you a pleasurable spike of dopamine.

This crazy chemical in love phase will last about 9 months (for most people – the occasional “swan” may last much longer), long enough for longer term attachment mechanisms to take effect. This is also long enough for there to be a high probability of bringing children into the mix, forming other (perhaps even more powerful) chemical attachments.

A host of biological and neurochemical changes have occurred in human evolutionary history to make us a pair-bonding species (mostly). Females no longer advertise their fertility with visible estrus, for example. Males invest heavily in their children, and have formed strong feelings of jealousy to help ensure that their mate’s children are indeed their own as well. Females trade faithfulness and perpetual receptiveness for a promise of male protection and providing for them and their children, and seem to wield a variety of psychological talents for manipulating their stronger partners into staying invested themselves.

At least, this all is the current neurbiological and evolutionary psychology explanation for romantic love. Much of it is based on at least reasonable evidence. The role of dopamine and oxytocin are fairly well described in animals, but human studies are still preliminary and it is not yet definitively proven that the animal data can be extrapolated to humans. The evolutionary psych explanations are reasonable but hard to prove, and likely filtered through cultural norms.

There is also a great deal of natural variability in human behavior related to romance and sex. The most obvious variable is gender attraction, but there are also variations in what people find attractive, as well as interest in sex. Some people have “fetishes” – specific things or situations that trigger an erotic response. It’s not clear why this happens – a quirk of brain development or just life experience.

The scientific view of love and romance can seem anything but romantic, and we can’t even let you have the scientific explanation without pointing out our current uncertainty and the need for more research. The fact is – love and romance are biological/neurological phenomena. They are being studied and we are slowly building a reductionist picture of exactly how and why we feel and act the way we do.

This view, however, is not incompatible with romance. It is a rationalist romantic view. Understanding biology is not inconsistent with embracing and even reveling in the human condition. Feelings of love and attraction are not diminished at all by an understanding of the possible evolutionary advantages of those feelings, or the underlying brain chemistry, any more than they are enhanced by ascribing those feeling to fate or magic.

Understanding the biology of love, rather, can be empowering.  Sometimes we make decisions that are not in our best interest because we are in the grip of neurotransmitters and evolutionary signals of which we are not consciously aware. Thinking that those feelings are due to some magical design of the universe or something akin to fate, or to forces outside of your control, are convenient justifications for giving in to feelings that may be leading you to bad decisions. It’s helpful to understand that evolution does not need you to be happy, just prolific. You, however, may prefer to be happy, and therefore may wish to make more reasoned decisions. It’s also helpful to understand the power of neurochemistry, and therefore perhaps it’s not a good idea to make rash decisions when you are in the grip of “romantic psychosis.”

A scientific understanding of our own brains does not lessen the feelings of love and attraction, but may help us to enjoy and embrace those feelings without being ruled by them.

Happy Valentines Day.