This week’s science column…

Love on the Brain

Copyright 2004 by Edward Willett

Ah, Valentine’s Day. Flowers and chocolates for the one you love…romantic dinners…dancing…candlelight…ain’t love grand?

Well, yes it is. It’s also fascinating fodder for scientists, for whom new research has revealed hints as to which parts of the brain are involved in the mysterious process of love.

The research makes use of functional magnetic resonance imaging. Magnetic resonance imaging (better known by its initials, MRI) uses radio waves and a strong magnetic field to provide detailed images of internal organs and tissues. Functional magnetic resonance imaging is a relatively new procedure that uses MRI to measure the tiny and fleeting metabolic changes that take place in an active part of the brain.

Helen Fisher of Rutgers University in New Brunswick, N.J., Lucy Brown of Albert Einstein College of Medicine in New York, and Arthur Aron of State University of New York in Stony Brook, New York, used fMRI to study the brain activity of 17 young men and women who had “just fallen madly in love” while they alternately looked a photo of their beloved and a photo of someone familiar but emotionally neutral, interspersed with a task designed to distract them.

The researchers hypothesized that the very intense early stage of romantic love is primarily associated with the brain’s reward system, and that is it primarily a motivation system, rather than a true emotion, oriented around the planning and pursuit of a pleasurable reward–an intimate relationship with a preferred mate.

The brain scans supported this hypothesis. Among the active regions of the brain were two (the right caudate nucleus and the right ventral tegmental area, if you must know) that are rich in a brain chemical called dopamine. An elevated level of dopamine enhances energy, focuses attention on new experiences, provides motivation to win a reward and produces a feeling of elation–all very much part of romantic love.

Prior to the fMRI, the participants took a questionnaire that allowed the researchers to rate them on a “Passionate Love Scale.” The participants who scored higher on the scale showed more activity in the caudate, one of those dopamine-rich areas, than those who scored lower.

Study participants who were in longer-term relationships showed more activation of emotion-related areas of the brain.

Men and women differed in their brain activity. Most of the women in the study showed more activity in areas associated with reward, emotion and attention, while most of the men in the study showed more activity in visual processing areas of the brain–including one associated with sexual arousal.

The researchers are working on a follow-up study involving using fMRI to scan the brain activity of men and women who have recently been rejected in love.

It’s all part of an effort to fully understand the range of brain systems involved in romantic love, a powerful force that has driven human culture in many different ways over the centuries, both positively (literature, music and art) and negatively (wars, murders, suicides).

Biologically, romantic love must serve some useful evolutionary purpose, or else it wouldn’t exist. According to these researchers, there are three primary brain networks that direct mammalian reproduction: the sex drive, attraction, and male-female attachment.

The sex drive evolved to motivate individuals to seek sex with any appropriate partner–evolutionarily speaking, it’s easy to understand, because any sexually reproducing species without a sex drive will soon be extinct.

The second primary brain network, attraction, is what the researchers believe developed into romantic love in humans. It evolved, they believe, to enable individuals to pursue preferred mating partners, as opposed to simply going after every available member of the opposite sex, thus conserving time and energy.

The third primary brain network involved in reproduction, male-female attachment, evolved, the researchers believe, to enable individuals to remain with a mate long enough to look after offspring. In some animals, this attachment is lifelong; in others, it lasts only until the offspring reach a certain level of development; in others, it seems to be non-existent.

In humans, you might say these three brain networks manifest themselves as the swingin’ single, the googly-eyed lovers, and the old married couple.

So what is love, scientifically speaking?

Our researchers have the answer: “Romantic love may be best classified as a motivation system or drive associated with a range of emotions.”

It may be an accurate description, but it’s not going to sell many Valentines.

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