Your Brain in Love

What does neuroimaging tell us about romantic love?

Posted Feb 11, 2016

John Graner, Walter Reed National Military Medical Center, public domain
Untitled, Default Mode Network, John Graner (2010)
Source: John Graner, Walter Reed National Military Medical Center, public domain

"Love looks not with the eyes but with the mind"

— William Shakespeare, A Midsummer Night's Dream

Can neuroscience, with all its talk of neuroanatomy and neurotransmitters, tell us something about love that doesn’t strip the subject of all the drama, emotion, and magic that makes it so salient, leaving us with a kind of giant buzzkill just in time for Valentine’s Day?

Seems unlikely, doesn’t it?

But let’s take a look. Over the past decade or so, researchers have been peering inside the brains of people in love with a romantic partner using a technique called functional magentic resonance imaging (fMRI) that reveals changes in blood flow and oxygenation during a specific task. Functional MRI results are presented as the now well-recognized, colorful images of the brain “lighting up” in specific situations – in the case of these experiments, while looking at a picture of and thinking about the person with whom the experimental subject is “in love.”

One of the first such fMRI studies, published in 2000 by Andreas Bartels and Semir Zeki at University College London, revealed that the areas of the brain activated by this task included the caudate and putamen, along with the insula and anterior cingulate cortex.1 A few years later, psychologist Arthur Aron and colleagues repeated a similar experiment and also found an activation pattern involving the caudate as well as the right ventral tegmentum area.2 Using control conditions involving the same subjects looking a pictures of close friends, the authors reported that these patterns of activation appear to be specific to romantic love. Subsequent studies by the same research group have shown that these brain areas seem to be active in both early-stage romantic love and long-term sustained love,3 as well as during the painfully intense and longing feelings of love in the wake of a break-up and rejection.4

These findings have been used by Drs. Aron and Helen Fisher, a biological anthropologist at Rutgers University, to frame a theory of romantic love as a “neural mechanism for mate choice.” According to this theory, romantic or passionate love is an important “drive” of human behavior, with a drive defined as a neural state that energizes and directs behavior to obtain a biological need.5 More specifically, romantic love is a “primary motivation system” geared towards courtship attraction and mate choice, in the ultimate service of our core evolutionary goal of reproduction. In contrast to mere sex drive which does little to focus our efforts to a single mate, it’s theorized that romantic love evolved among mammals to promote a kind of directed, longer-term attachment that would lead two mates to remain together long enough to raise their offspring.6

Of course, that’s little more than basic Evolution of Love 101, so how do the neuroimaging studies inform this theory? The authors of these studies note that the key areas of the brain that light up during romantic love – the caudate, putamen, and ventral tegmentum – are “dopamine-rich” regions that form the brain’s “reward system,” supporting the idea that love is associated with the experience of the kind of pleasure that, like eating our favorite foods, reinforces behavior.6 These same brain areas are activated during drug use and are implicated in models of addiction, leading Dr. Fisher and others to suggest that romantic love may itself qualify as a kind of addiction.7 These brain areas also seem to be an important place of activity for the hormone vasopressin, which is thought to play a role in regulating partner preference, pairbonding, and attachment.6 And finally, these areas are “subcortical” structures, meaning that they operate below the level of conscious thinking, as part of our more primitive “reptilian” brain.

It’s therefore claimed – in the likes of articles that explain “what neuroscience can teach us about love” – that these studies prove, or at the very least provide a scientific framework for, such truisms as “love is obsessive,” “love is prone to recklessness,” and “intense romantic love can last a lifetime.” Dr. Fisher herself has taken such claims to the bank (in addition to being a researcher, she’s the Chief Scientific Advisor to Match.com as well as the author of multiple books, including the just-published Anatomy of Love: A Natural History of Mating, Marriage, and Why We Stray), suggesting that her findings provide us a biological explanation of “why we love” (see her TED Talk, The Brain in Love).

As a theory, it all makes a lot of sense. On a functional level, we love romantically because this kind of love leads to both reproduction and child-rearing, enhancing our evolutionary success. On a mechanistic level, this kind of love is intense, obsessive, and largely unfettered by free will because it’s governed by the areas of our brain that drive such behavior.

But before we declare that neuroscience proves anything about love, let’s apply a little conservative skepticism and take the findings with the grains of salt that they deserve. For one thing, does looking at a photograph and thinking about our lovers while lying alone inside an MRI scanner really invoke feelings of romantic love? Maybe for some study subjects, what was being captured wasn’t love at all, but a feeling of claustrophobia. Or maybe they were just really hungry. This is a common issue with psychological experimentation in general, that what’s measured in the lab might not be the same as the thing the experimenter is really looking for.

Next, there are several specific limitations of fMRI worth mentioning. To begin with, a well-known limitation of fMRI findings is that they only provide averages and approximations of brain activity that can vary considerably based on parameters set by an investigator. For example, rather than looking at the entire brain, Dr. Fisher and Aron’s studies only looked at 12 brain “regions of interest” informed by earlier work, suggesting that other areas of the brain might have lit up had they expanded their search.8 Indeed, a more recent neuroimaging study by Hongwen Song and associates found significant activation in other brain areas such as the amygdala,9 which was found to be deactivated in several of the studies mentioned above.

So who’s to say what’s really being consistently activated in romantic love? Isn’t it likely that, just as romantic love has infinite variety across different individuals and situations, there’s just as much variation in terms of what’s going on in the brain? It’s therefore misleading to think that fMRI images averaged from a handful of subjects accurately reflect what it looks like when your brain is in love, as if it’s one thing.

Another limitation of fMRI is that, despite how its findings are popularly interpreted, it’s not really right to think of the brain as consisting of separate and discrete functional units of the mind.10 The brain is more properly thought of as a series of interconnected circuits, with specific areas often involved in a wide variety of functions. For example, the caudate – one of the areas that seems to consistently light up in the above studies – is also a key area that regulates movement, just as dopamine is a key neurotransmitter for motor activity. But what, if anything, does movement really have to do with romantic love?

Researchers often work backwards in interpreting fMRI studies, trying to get the data to fit the theory. A certain brain area lights up during an experiment and we then try to imagine why, searching through a lens of cognitive bias for an explanation that fits our preconceived expectations. So, if movement doesn’t seem to be obviously relevant to romantic love, then we can just leave that aspect of caudate and dopamine functioning aside.

We’re on safer scientific ground if we allow the data to inform the theory, rather than the other way around. For example, Dr. Fisher highlights the subcortically-mediated primal drive of romantic love, but both her findings as well as those of other groups also reported significant activation of the cingulate cortex, a “higher” area of thinking and consciousness. Song and colleagues hypothesized that this supports the idea that romantic love involves the “social cognition network.”9 But then how do we reconcile these two seemingly opposing views – is love a primal drive or an act of rational decision makers?

By way of explanation, Dr. Fisher highlights some important differences between fMRI studies, noting that cingulate cortex activation seems to be a feature of longer-term romantic love. This invites the familiar idea that love in this stage may become more of a conscious decision than a feeling, but if that’s so, why do the subcortical areas still remain activated for so long?

Such inconsistencies probably reflect what we already know, that love is much more complicated that it might seem in a colorful fMRI image. The point isn't that we can’t contrive an explanation for the neuroimaging findings, it’s that the findings shouldn't be mistaken for the explanation. When looking at fMRI results, we have to take care not to fall into a trap of neuro-reductionism.

Put another way, Paulo Fusar-Poli and M.R. Broome caution that “neuroimaging findings should not be mistaken as validation of our ordinary view of the world.”11 They call this mistake the myth of “neuro-realism” and suggest that it frequently gives rise to unsubstantiated claims of “folk neuroimaging” in the popular press. Just so, after some of the studies mentioned above were published, several articles followed – coming from sources like Esquire, Huffington Post, and DailyMail.com – implying that neuroimaging might be a viable tool to tell if our lovers really love us, or us them. Suspect your husband is cheating and doesn’t love you anymore? Stick him in an MRI scanner and you’ll know for sure. The cost of such an expensive lie detector test and the problem of false negatives aside, Alva Noe got it right when she wrote (at npr.org on a related subject) that an MRI scan can’t really tell us anything about personhood and that “if you have to ask, you’ll never know.”

So, does neuroimaging really reveal something that we didn’t previously know about romantic love? Not exactly. Neuroimaging doesn’t tell us that love is obsessive, or addictive, or long-lasting. We already knew all of that. What areas of brain activation add – as one piece of a forming puzzle – is a better understanding of love as a biological process. And what that provides is not so much a meaningful reveal about “why” we love, as Dr. Fisher suggests, but rather an alternative perspective on how we love, with our brains.

Among other things, a biological model of this sort might open the door to something for which human beings have been searching for millenia – the ability to manipulate romantic love chemically.12 Indeed, biological research on romantic love has already highlighted the possibility that the hormone oxytocin could be taken to improve commitment in relationships and to “treat” infidelity as a kind of neuroenhancing “cuddle drug.” It might even find a darker, if hardly novel, niche as a modern-day “love potion/roofie.” But an enhanced biological understanding of love need not only be about pharmaceuticals – it could just as easily help us develop more effective psychotherapeutic interventions for overcoming the pain of a break-up.

As to whether all this talk of biology and brains amounts to a Valentine’s Day buzzkill, let’s read how Drs. Fisher, Aron, and co-author Lucy Brown – a psychologist, anthropologist, and neuroscientist – describe romantic love:

“Romantic love begins as an individual starts to regard another individual as special and unique. The lover then focuses his/her attention on the beloved, aggrandizing the beloved’s worthy traits and overlooking or minimizing his/her flaws. The lover expresses increased energy, ecstasy when the love affair is going well and mood swings into despair during times of adversity. Adversity and barriers heighten romantic passion, what has been referred to as ‘frustration attraction.’ The lover suffers ‘separation anxiety’ when apart from the beloved and a host of sympathetic nervous system reactions when with the beloved, including sweating and a pounding heart. Lovers are emotionally dependent; they change their priorities and daily habits to remain in contact with and/or impress the beloved. Smitten humans also exhibit empathy for the beloved; many are willing to sacrifice, even die for this ‘special’ other. The lover expresses sexual desire for the beloved, as well as intense sexual possessiveness, mate guarding. Yet the lover’s craving for emotional union supersedes his/her craving for sexual union with the beloved. Most characteristic, the lover thinks obsessively about the beloved, ‘intrusive thinking’. Rejected lovers first experience a phase of protest, during which they try to win back the beloved and often feel abandonment rage; then they move into the second stage of rejection, associated with resignation and despair. Romantic love is also involuntary, difficult to control and generally impermanent.”6

Not quite Shakespeare and not much we didn’t already know, but it sounds about right, with a little added biological perspective to help us understand the bigger picture and unraveling complexity of our brains in love.

Dr. Joe Pierre and Psych Unseen can be followed Facebook at https://www.facebook.com/psychunseen and on Twitter at https://twitter.com/psychunseen. To check out some of my fiction, click here to read the short story "Thermidor," published in Westwind earlier this year.

References

1. Bartels A, Zeki S. The neural basis of romantic love. NeuroReport 2000; 11:3829-3824.

2. Aron A, Fisher H, Mashek D, Strong G, Li H, Brown LL. Reward, motivation and emotional systems associated with early-stage intense romantic love. Journal of Neurophysiology 2005; 94:327-337.

3. Acevedo BP, Aron A, Fisher HE, Brown LL. Neural correlates of long-term intense romantic love. Scan 2012; 7:145-159.

4. Fisher HE, Brown LL, Aron A, Strong G, Mashek D. Reward, addiction, and emotion regulation systems associated with rejection in love. Journal of Neurophysiology 2010; 104:51-60.

5. Fisher H, Aron A, Brown LL. Romantic love: An fMRI study of a neural mechanism of mate choice. The Journal of Comparative Neurology 2005; 493:58-62.

6. Fisher H, Aron A, Brown LL. Romantic love: A mammalian brain system for mate choice. Philosophical Transactions of the Royal Society B 2006; 361:2173-2186.

7. Reynaud M, Karila L, Blecha L, Benyamina A. Is love passion an addictive disorder? The American Journal of Drug and Alcohol Abuse 2010; 36:261-267.

8. Ortigue S, Biachi-Demicheli F, Patel N, Frum C, Lewis JL. Neuroimaging of love: fMRI meta-analysis evidence towards new perspectives in sexual medicine. Journal of Sexual Medicine 2010; 7:3541-3552.

9. Song H, Zou Z, Kou J, Liu Y, Yang L, Zilverstrand A, Uquillas F, Zhang X. Love-related changes in the brain: a resting-state functional magnetic resonance imaging study. Frontiers in Human Neuroscience 2015; 9:1-13.

10. Logothetis NK. What we can do and what we cannot do with fMRI. Nature 2008; 453:869-878.

11. Fusar-Poli P, Broome MR. Love and the brain: From mereologic fallacy to “folk” neuroimaging. Neuroimaging 2007; 154:285-286.

12. Young LJ. Love: Neuroscience tells all. Nature 2009; 457:148.