One of the problems though, is that you’re asking people to look at a picture of their romantic partner for 20 seconds and think romantic thoughts, and then you’re asking them to cut that feeling off and look at another face and just feel neutral. The problem is that the person could still be thinking of their partner, so how do you cut off that romantic feeling? A great way to cut it off (this is a practical note for people who want to cut off a romantic feeling) is to count backwards by seven from a large number like 2011.
So, we alternatively showed the subjects a picture of their romantic partner, and then a number like 2011. The instructions were to then count back by seven. After this, they were shown a picture of the neutral person (emotionally neutral), for 20 seconds. They either recall memories of that person, or just keep looking at their face. Then we had them do the counting backwards task, and then had them look at a picture of their romantic partner again, and so on.
The person is in that scanner doing that task for about 15 minutes. We also collect an anatomical scan, and then merge the anatomical data with the functional data from the scanner. You are inducing these feelings of romance in a person and then you’re comparing those feelings of romance to feelings of another neutral person.
BW: Once you have the two comparisons, what are you looking for in the fMRI?
LB: We are looking for changes in blood flow, which means there will be changes in oxygen and glucose demand. It’s just like using a muscle. When you use it a lot, you get increased blood flow and therefore increased oxygen and glucose delivery to it. Nerve cells, when they work hard, need oxygen and glucose too and right in that moment. Muscles actually take a little longer and we’re lucky that we can see these changes in the brain right away. So that is the signal that we are looking at. It’s an index of the metabolic demand made by the nerve cells, and what we find is that — this has been replicated many times — people who are in the early stage of romantic love, even if they have been in a loving marriage for 20 years, say that they are still in love with their partners. They increase activity in these primitive reward systems of the brain.
BW: Does dopamine and oxytocin play a role in the formation of romantic love?
LB: Hormones like dopamine and oxytocin are critical for romance and attachment. We just don’t know what comes first and how these things start really. We just have hypotheses about it. For example, we know that big parts of the dopamine system are activated, but we don’t even know for sure that it is dopamine. We’re assuming this because it is involved in many addictive behaviors considered so typical of romantic love.
Also, we think of oxytocin as being more involved in attachment and longer-term relationships. That’s because it has been shown in animals in instances of long-term pair bonding. We’ve seen in some of the human studies that the part of the brain that contains the oxytocin receptors is active later in relationships. And the trouble is that it’s pretty critical to have the dopamine system active in order to have this system.
BW: So when you do the fMRIs, what parts of the brain are the most activated?
LB: So it’s the ventral tegmental area, which is part of the brain stem and is involved in romantic love, and the caudate nucleus. This nucleus receives messages from the ventral tegmental area and it all happens in milliseconds. So, you’re able to look at the entire brain, and you look for areas of the brain that have changed consistently over repeated trials.
When the subject is looking at the person they don’t know or have no attachment to, there is almost no reaction. Now, when the person is looking at their romantic partner, there is a clear reaction.
BW: Has anyone observed this reaction in any other mammal, like a dolphin?
LB: No, there have never been any other studies about this. But there’s a huge body of research pertaining to attraction and pair bonding in prairie voles. There are two types: mountain prairie voles and meadow voles. They are genetically just a little bit different.
One is promiscuous and the other practices pair bonding — and there is a part of the brain that is responsible for this. Oxytocin is on the map because of these studies. And they then went in and changed the gene in the promiscuous ones and made them pair bonding voles, so this research influenced our whole idea a lot.
BW: What are some observations you may have made about the process of falling in romantic love?
LB: Romantic love is part of the brain’s survival system. Even the people who go without romantic love have a community or some sort of attachments that are helping them survive. When you pair up with someone, it’s protection. It also helps you find resources. If it’s more than one person looking for food, it’s more likely that they’ll find it and share it. I mean, you don’t necessarily need romantic love but it is helpful, especially if you’re going to have children.
BW: How does the beginning stage of romantic love flourish into a long-lasting, emotionally lucrative bond?
LB: [Laughs.] Everyone would like to know that. Relationships involve laying down memories about your experiences with the other person. The more developed parts of your brain, those that are newer, make decisions about whether these experiences are really such a good idea. It can take a while to find out about people.
By the way, another important thing about this is that these systems are at the unconscious level, which makes them so hard to control.
Over time, experiences with that person play on the attachment systems, which are newer parts of the brain. The attachment system needs a lot of positive reinforcement. You need a lot of positive experience with the other person in order to keep the relationship going.
We were built to be addicted to people and I consider love a natural addiction.
This article was first published in Brain World Magazine’s Fall 2015 issue.
More From Brain World
- Basic Chemistry: Unraveling the Mysteries of Love, Sex, and Commitment
- Having Good Chemistry: How Being in Love Changes The Brain
- In Love With Love: The Science of Love Addiction
- Know Your Brain: Oxytocin — The “Love Hormone”
- The Love Revolution: How A New Brain-Centered Therapy May Save Relationships
- Spending Your Identity: Can Money Buy Happiness After All?
