We tend to think of emotional states as being quite separate, probably because the objects toward which they are geared are separate. I think that most people, if asked whether love is the same as drug addiction, would say that it wasn’t. However, the fact that both love and drug addiction activate exactly the same areas in the brain, would indicate that they are not only very similar, but that both could make people act in similar ways.
Professor Jim Pfaus
Unlike our romantic forebears, we now know that love resides in the brain rather than in the heart. However, exactly where in the brain this feeling is located, and the relationship that it enjoys with sexual desire, has not been fully understood. That is, until now.
An international team of researchers has developed a complete map of love and desire in the human brain, by analysing the results of 20 separate studies. They identified two brain structures – the insula and the striatum – that are responsible for tracking the progression from sexual desire to love.
I spoke to Jim Pfaus, Professor of Psychology at Concordia University, to find out more about his neurological mapping of phenomena traditionally considered to be unfathomable. I began by asking Professor Pfaus what inspired him to try to identify the locations of love and desire in the brain.
"This was actually the result of a very long process," he explained. "People have been studying the two in isolation for quite some time, and the idea of investigating whether one builds on the other, or whether they are completely separate, represented a major question in understanding the more cognitive aspects of emotion.
"We tend to think of emotional states as being quite separate, probably because the objects toward which they are geared are separate. I think that most people, if asked whether love is the same as drug addiction, would say that it wasn’t. However, the fact that both love and drug addiction activate exactly the same areas in the brain, would indicate that they are not only very similar, but that both could make people act in similar ways.
"One way to find out whether love and desire are similar or different is to see whether there is any overlap between the two. That’s why we decided to conduct a meta-analysis. A broad range of methods are used to study these issues. Some ask participants to rate their own sexual desire, some ask them to look at pictures or movies of people having sex. You might assume that completely different areas of the brain would be activated depending on whether a subject is presented with a movie or a picture, but it turns out that this is not the case.
"There is a lot of commonality in terms of the activation that occurs. There is also commonality between men and women, in terms of that activation. We talk a lot about sex differences, and I certainly believe that they exist, but when it gets down to the level of the cortex, men and women experience love in the same way; the activational patterns are the same."
This commonality is not confined to humans, however. Professor Pfaus went on to explain how similar mechanisms have been observed in rodents.
"What struck me as really interesting was the fact that in rat and vole literature on sexual bonding, and particularly that interested in the mechanisms of sexual desire, the evidence suggests that things are very similar," he said. "Our study prompted me to go back and to look at previous experiments, and sure enough, I found similar activation of the insula in animals that are conditioned to associate certain odours with sexual reward. Rats exhibit elements of pair-bonding with other rats that carry these odours. This comparison made me and my co-authors begin to consider the real possibility that there is a common mammalian system for bonding.
"Dr Larry Young, Principal Investigator at The Young Lab of Emory University, believes that this is probably derived from maternal bonding as a mechanism to protect one’s offspring. You’re going to bond with and protect your offspring, and if anybody tries to steal them, you’re going to get angry.
Evidence demonstrates that love and drug addiction activate similar brain patterns
"Well, imagine that romantic love usurps a portion of this pathway. When you fall in love with your partner, who is essentially a resource, you feel ownership and entitlement over them. Drug abuse follows the exact same process. The striatum is an area that translates motivation into action; especially motivation towards things that are pleasurable. We like to be critical of pleasure in our culture, but in fact, it is probably the prime mover of everything. It is the only way for you to know whether something is good or not. Pleasure is the great driver of everything, so you need a system capable of translating distal cues into a prediction of that pleasure. You can then move towards these cues. This begs the question, if we can experience love at first sight, does this not necessitate an intense desire to have sex with that person?"
The team, which included researchers from Concordia University, Syracuse University, West Virginia University, the University of Geneva, the University Hospital of Geneva and the Maurice Chalumeau Foundation, found that love and sexual desire activate different areas of the striatum. The area associated with desire tends to be triggered by things that are immediately pleasurable, such as sex or food. The area associated with love, on the other hand, involves conditioning whereby things paired with reward or pleasure are given inherent value. Essentially, love is a habit that forms as sexual desire is rewarded. I asked Professor Pfaus whether or not these findings imply that love is dependent on the fulfilment of sexual desire.
"I think that romantic love is," he answered. "From a clinical standpoint, when the sexual reward goes out of a relationship – when that intense pleasure is no longer present – that’s when couples start to experience serious problems. Cat Stevens was right; the first cut is
the deepest. I think that we are always trying to maintain that intense pleasure, so when habit comes into play, it can be both good and bad.
Perhaps one of the most surprising of the study’s findings was the fact that love and drug addiction are so similar to one another.
"Dr Anna Rose Childress, Associate Professor at the University of Pennsylvania’s Department of Psychiatry, conducted a study in which she took cocaine addicts, recreational cocaine users and non-users, into an FMRI machine," outlined Professor Pfaus. "The participants were showed either cocaine-related cues or sex-related cues. To me, this is one of the most brilliant studies ever done, because she discovered that cocaine addicts exhibited striatal activation to the cocaine-related cues but not to the sex-related cues, recreational users had a mild activation when presented with the cocaine-related cues but a much more intense reaction to the sex-related cues, and non-users experienced a strong reaction to the sex-related cues but no reaction whatsoever to the cocaine-related cues. This kind of disassociation really tells us something important. Whatever gets there first is the winner; it garners your attention. Essentially, the brains of cocaine abusers are saying, ‘Even though you are naked in front of me, I’m a coke-head. I am not responsive to you because I am in love with my drug.’
"Also, researchers can now compare their studies with the map that we have created. We hope that it will form a template in social neuroscience, so that people can see whether similar cortical structures are activated in circumstances other than romantic love."
Despite the best efforts of modern neuroscience, many traditionalists would still contend that romantic love is intrinsically linked to the heart. I concluded our interview by asking Professor Pfaus whether the romantics had gotten things completely wrong. Does love have nothing to do with the heart whatsoever?
"You feel it in your heart," he conceded. "Well, you feel it in your blood and without the heart, you don’t get the blood. This is also the case when you are sexually desirous of somebody. This situation typically translates into sexual arousal, which means that the blood has got to flow from point A to point B. Essentially, you want it in your genitals.
"The old stress researcher Dr Hans Selye used to talk about good stress and bad stress. He believed that love and especially sexual desire, were good stresses. Of course, being potentially eaten by a bear in the woods would induce bad stress. Both of these scenarios are going to affect the heart in similar ways, such as increased heart rate. If you have no context in which to put this sensation, you would probably get freaked out. However, if you are able to say, ‘This is love’ or, ‘This is fear’, an increased heart rate can have meaning.
"We might also feel pining for an absent loved one, and we might say that our heart aches for that person, but really, the organ that makes this all happen is the brain."