Science Tries to Make Sense of Love

Why We LoveWe’ve spent a good portion of our anthropological and cultural history trying to work out what love really is, and the jury’s still out. “There’s no clear single definition,” says UWA psychologist Helen Street. “Rather, love is defined culturally and socially. We need other human beings to become people, we need a sense of belonging and emotional connection. If we find people that give us those we want to be around them, and that desire can be described as love.”

Now that cognitive and neural science is giving us a window into our own inner workings, we might start to see some clues about the age old questions of what love is and how we can make it last. It’s all to do with the difference between romantic love, sexual excitement and feelings of attachment, and brain chemicals like dopamine, oxytocin and serotonin all play a part.

In her groundbreaking book explaining love’s biological basis Why We Love, American anthropologist Helen Fisher explains how the levels of vasopression associated with a long term, loving partnership can quell the chemicals that play a part in romantic love and sexual arousal, which partly explains the frustrating way romance seems to fade over the years. But knowing such biology gives us the opportunity to ‘cheat’ our nervous system.

The reason a new love affair is so exciting and all consuming is because of testosterone and dopamine levels, which combine to give us that delicious urge to spend the first few months staying in bed together and flood us with feelings of reward and satisfaction. Doing something novel like going on holiday or trying a new restaurant with your partner triggers the chemicals that respond to new experiences, so you’ll also get a spike in the neural cocktail that prompts romantic love for your partner.

But why did we end up this way over our 2 million year evolution? The act that propagates our species lasts only minutes yet we willingly sign up for all the hardship, stress, bitterness and boredom that can result from spending our lives with one person.

Fisher describes one confluence of behaviours and mechanics that might have helped our ancestors survive if they stayed together for at least four years (the natural ‘birthing cycle’ of our species — coincidentally a common length of time before many couples divorce).

There’s a movement in anthropology that contends cooking is the cornerstone of human intelligence, a theory crystallised by primatologist Richard Wrangham’s 2009 book Catching Fire: How Cooking Made Us Human. In chemical terms cooked food is partially digested, giving us much more metabolic energy per unit we consume and promoting our characteristic brain size. Nature then compensated for such a large head by having females deliver offspring far earlier in foetal development. It was easier on the narrow female birth canal but it meant a much longer period of vulnerability.

So — as Fisher believes — our ancestral mothers had to spend several years carrying us around instead of using her arms to defend and feed herself. The best way to protect her and the baby was to encourage the male who impregnated her to want to stay around, and the biological mechanism that gave parents so much combined investment in their family was love.

But as a million rock songs and movies well know, love can be as crushing as it is transcendent. Rejection, loneliness, jealousy and even the death of a spouse are all part and parcel of the neurochemical package. In pre-language days, Fisher’s work sets out how the sluggish despondency of sadness was probably a signal to the tribe about our state of misery, encouraging them to cheer us up to be a productive member of the very vulnerable group again.

As Why We Love describes, the interplay of brain chemical levels is carefully regulated and just because dopamine is the satisfaction/reward hormone doesn’t mean too much isn’t bad for you. When the object of our affection rejects us it sends dopamine and norepinephrine levels soaring and can reduce mental controls that normally hold us back from the murder, suicide or other violence we sometimes see resulting from love gone wrong.

Drugs like cocaine also give the brain a similar high to the euphoria of falling in love, which explains not only the addictive nature of love and lust but the opportunities to abuse our brains’ natural chemical pathways artificially and harmfully.

They say the loss of a spouse or a job are the most stressful events in life, and Helen Street thinks the reason is because we’re losing an essential part of ourselves. “A large part of our identity is really a social identity,” she says. “How we see ourselves as people is totally wrapped up in the people we meet and spend time with in our life.”

As to what love is, we’re physiologically capable of mating with any fertile member of the opposite sex, but that doesn’t mean we want to. Something drives us towards one special person. Whatever that drive comprises, it must be love.