Since the days when our ancestor Australopithecus first sauntered across the African savannah, love has been one of the most cherished and enduring mysteries of nature. It’s hard to define, but we sure know it when we see it (or feel it).
We’re physiologically capable of mating with any member of the opposite sex, after all, but that doesn’t mean we want to. Some sense of emotional and sexual urgency drives us towards that special someone — even animals exhibit behaviors indicating that they’re attracted to specific mates.
The reason love is so hard to pin down scientifically isn’t just because it takes so many different forms (between friends, parents and offspring, pets, etc.) but because it’s not so much a part of the evolutionary urge as we first assumed. Some romantic love — like homosexuality, or the schoolyard crush we experience long before sexual maturity — serves no reproductive purpose at all.
But following the work of behaviorists, neuroscientists, and evolutionary psychologists, we might be on the verge of unpacking the deepest, oldest drive known to humanity.
Love as Chemistry
As with every other state of being, love’s origin has to do with the balance of hormones and neurotransmitters in the brain. In Survival of the Nicest (2014), science author Stefan Klein tells us what the brain hormones vasopressin and oxytocin (collectively known as vasotocin) do.
Both are produced in the posterior pituitary gland and studies on animals have shown they play a part in pair bonding and social hierarchy. Oxytocin is the chemical that contributes to feelings of elation during an orgasm, and the female brain also gets a burst of it during labor — which is thought to help the mother bond with the developing baby.
The other ingredients of love we find in the neurological soup include dopamine, norepinephrine, testosterone, serotonin and lots more associated with reward, pleasure, attachment and its suppression (which we’ll hear more about later).