The science behind love at first sight

From the moment she set eyes on him, she adored him. Wanting only to be near him, to lavish her affection on him, she followed everywhere he went. The sound of his voice made her bark.

Bark? Novelist and animal behaviorist Elizabeth Marshall Thomas was describing her pug dog, Violet, who was in love with her other pug, Bingo.

Animals love. Animal literature is full of descriptions of love at first sight, actually. When Tia, a female elephant living in the Amboseli National Park in Kenya, came into heat (or estrus), she was followed by a coterie of young males. Tia would not cooperate. But the moment Bad Bull swaggered into view, head high, chin tucked in, ears intensely waving, trunk aloft, and doing his courtship strut, Tia changed her elephant mind. Holding her ears high in a pose meant to draw his attention, she stared at him with the prolonged “courting gaze,” then turned and began to move slowly away, glancing repeatedly to see if this mature male was following. Tia and Bad Bull remained inseparable for the duration of her estrus.

Instant attraction across the animal kingdom

Scientists and naturalists have recorded this instant attraction phenomenon in hundreds of species. Throatpatch and Priscilla, two orangutans; Alexander and Thalia, two baboons; Skipper and Laurel, two beavers; Misha and Maria, two Huskies; Satan and Miff, two chimps: these and many other creatures have taken an instant liking to one another. As Charles Darwin wrote of two ducks, “it was evidently a case of love at fist sight, for she swam about the newcomer caressingly… with overtures of affection.”

How we came to fall in love fast

You and I have inherited the brain circuitry for this instant attraction, what has become known as “love at first sight.” This spontaneous passion comes from our primordial past when, like other mammals, our female forebears had a monthly period of heat. Like all mammals that have only a few hours, days or weeks to procreate, these ancestors had to become attracted quickly. They couldn’t spend two months or two years discussing their suitor’s career and family plans. They had to meet and produce offspring fast.

Today, first meetings are still crucial. With little or no knowledge of this stranger, we tend to weigh heavily those few traits we first encounter. Based on these morsels of information, we almost instantly form a strong opinion of him or her, generally within the first three minutes. Thomas Jefferson fell in love with Maria Cosway in an afternoon, probably within minutes of meeting.

Who falls faster: the male or the female?

Indeed, men tend to fall in love faster than women do, probably because their brain circuitry for romantic love is more quickly triggered by visual cues. But any of us can walk into a crowded room, talk for only minutes with a someone new, and either feel that “chemistry” — or “know” there could be chemistry down the road.

But is this attraction love or lust? Actually, these feelings involve very different brain networks. You can have physical intimacy with someone you are not “in love” with, and you can be passionately in love with someone you have never kissed. But these brain circuits can trigger one another, leaving you wondering for a moment if your attraction is purely physical.

Can immediate attraction last?

You will know if your passion is love or lust with your answer to just one simple question: “What percentage of the day and night do you think about him or her?” Romantic love is an obsession. It can happen in a moment, but when it strikes, you can’t get your new beloved off your mind. And this instant passion can last — sometimes for many years.

“The loving are the daring,” wrote poet Bayard Taylor. We are all daring; we can’t help ourselves. Millions of years ago humanity evolved three powerful brain systems for courtship and reproduction: the libido, romantic attraction, and feelings of deep attachment. The libido evolved to drive us to reproduce with a range of partners, but romantic love evolved to enable us to focus our energy on just one, The One. This passion is intricately orchestrated, at least in part, by the activity of a powerful chemical, dopamine. And this potent brain circuit lies dormant in each of us, sleeping like a cat with one eye open, waiting for the right moment to erupt.

Indeed, feelings of intense romantic passion can awaken the first moment you see someone who fits within your mental concept of the perfect partner — love at first sight.

Helen Fisher, Ph.D., is research professor, Department of Anthropology at Columbia University; author of Why We Love; and is chief scientific advisor to www.chemistry.com.