Love on the brain

Love is a topic that scientists have shied away from – perhaps in the same way as studying humour, they worry that they will take the magic out of it. But as Helen Fisher, one of the foremost researchers of love says, you can know all the ingredients of chocolate cake and it will still taste delicious.

One of the more popular early theories was Sternberg’s triangular theory of love. This theory has immediate appeal because it points out three aspects of loving relationships that we can instantly recognise – intimacy, passion, and commitment. A relationship can have any two or all three of these, and in the theory, each combination has its own name (see this article for more on that).

It’s a nice, tidy model. But one problem I first had with it, is that maybe it only has intuitive appeal because I recognise it in Hollywood movies, rather than in people. Is this love?

It may be: Sternberg’s model matches up nicely with some work in neuroscience and animal behaviour. It seems that there are discrete but interrelated emotional systems common to most if not all mammals and birds, which solve the ‘problem’ of mating. These are lust, attraction, and attachment, and they correspond roughly to Sternberg’s passion, intimacy and commitment. Example behaviours are:

  • Lust / passion – craving for sexual gratification, associated with elevated levels of estrogens and androgens.
  • Attraction / intimacy – increased energy spent on the preferred mating partner, in humans this also includes ‘intrusive thinking’ about the love interest. Associated with increased dopamine and norepinephrine, and decreased serotonin.
  • Attachment / commitment – Characterised by mutual territory/resource defence, nest building, close proximity, separation anxiety. Associated with the neuropeptides oxytocin and vasopressin. (see references 1 and 2 for a review of this evidence)

These are powerful chemicals, and the power of love should not be underestimated; in one study, evidence of romantic attraction was found in 147 of 166 societies (3). People elope together because of love, they sing songs because of love, and they kill themselves – and others – because of love. Clearly, it is more than a feeling. What is actually going in this attraction / intimacy part of Fisher/Sternberg’s models that has such a maddening effect on us?

To find out, Helen Fisher stuck a bunch of madly-in-love people in fMRI scanners, while showing them pictures of their loved one. The results? It appears that romantic love is located primarily in the ventral tegmental area of the brain. This is part of the dopaminergic system, involved in reward, want, and craving. It’s the same area of the brain that fires up when addictive drugs are taken, particularly cocaine and the amphetamine derivatives. In other words, love is addictive – literally.

But of course, every rose has its thorn, and love does not always end well. In another interesting study, Fisher and colleagues stuck people who had recently been dumped into an fMRI (4). Where is this experience located in the brain? The same place! But additionally, there was also activation in the nucleus accumbens, an area associated with judgements of gain and loss; the area that lights up when we’re willing to take great risks to achieve a high perceived gain – the same area involved in gambling. This is why we get people going to great lengths to get their love back – they are simultaneously focused on what they have lost and at the same time more likely to take high risks.

So what is love? It is an addiction. It meets the criteria necessary for something to be classed as an addiction (tolerance, withdrawal, relapse). The implications of the above findings are massive – if love is associated with the above neuotransmitters, peptides and hormones, then our experience of love could be influence by anything that interferes with these chemicals – recreational drugs and anti-depressants in particular. In addition to this, the brain areas involved in love seem to suggest that, rather than being an emotion per ce, it is a goal-oriented state.

(Credit: txd)

But, at the risk of leaving on a low note, I’ll finish by mentioning a recent study by the same research team (5). So fond of sticking people into fMRI scanners, this time they scanned couples who had been married for 25+ years, and still report feeling in love with their partners. What was the brain activity in these couples? As Sternberg would predict, they showed greater activity in areas associated with long-term pair bonding in animals. But what about attraction / intimacy? Well, they found just the same activity as they did in the earlier experiments. Perhaps true love can last forever.

PS. The titles of five love songs are hidden in this article. See if you can find them!

Recommended Reading:


(1) Fisher, H. (1998). Lust, attraction, and attachment in mammalian reproduction. Human Nature, 9(1), 23-52.

(2) Fisher, H., Aron, A., Mashek, D., Li, H., & Brown, L. (2002). Defining the brain systems of lust, romantic attraction, and attachment. Archives of Sexual Behavior, 31(5), 413-419.

(3) Jankowiak, W., & Fischer, E. (1998). A cross-cultural perspective on romantic love. Human emotions: A reader (pp. 55-62). Malden: Blackwell Publishing

(4) Fisher,H, A Aron, G Strong, DJ Mashek, H Li, LL Brown. (2005). Motivation and emotion systems associated with romantic love following rejection: an fMRI study.

(5) Aceveda, B., Aron, A., Fisher, H., Brown, L. L. (2008). Neural correlates of long-term pair-bonding in a sample of intensely in-love humans. Poster Session#297, Society for Neuroscience, annual meeting

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