Loving-Kindness on the Brain
"The feeling people get when their brains release oxytocin is one of empathy or emotional connection
Paul J. Zak is founding director of the Center for Neuroeconomics Studies at Claremont Graduate University. He has a Ph.D. in economics from University of Pennsylvania, and post-doctoral training in neuroimaging from Harvard. Dr. Zak's lab discovered in 2004 that an ancient chemical in our brains, oxytocin, allows us to determine who to trust. His new book is The Moral Molecule: The Source of Love and Prosperity. Dr Zak will be speaking at the Humanist Community Center in Harvard Square on May 20, 2012. The following is an edited version of our exchange, conducted by phone and email.
TNH: In a nutshell, what are the findings of your research on love and empathy?
Zak: In experiments run over the last 10 years, in my lab and in the field, we've shown that the brain chemical oxytocin is released when someone is nice to us in objective ways (for example, when a stranger shares money with us). Oxytocin is the mammalian signal that tells mothers (and in some species fathers) to care for their offspring. It is the chemical basis for parental love. What we've shown is that oxytocin release is stimulated by acts of kindness or trust by complete strangers. The feeling people get when their brains release oxytocin is one of empathy or emotional connection.
TNH: You write that empathy is the product of a brain circuit you call HOME (for Human Oxytocin Mediated Empathy). How does this brain circuit work?
Zak: Oxytocin does not work alone. It activates a brain circulate that makes it feel good to do good for others. The HOME circuit does this by giving us a feeling of pleasure when we help others and by reducing our anxiety when we have a positive social interaction. Our brains are designed to engage with strangers and to care about them. This is what it means to be a social creature.
TNH: There is a clear distinction between romantic love and non-romantic love. But with regard to non-romantic love, such as love for one's family, friends, for humankind in general, are there clear biological distinctions between these different subcategories of love? Is the oxytocin circuit at the core of all these types of love?
Zak: Biologically they appear to be quite similar and to use oxytocin and the HOME circuit. They may feel differently, but nature is conservative and reuses brain circuits for many purposes. I think this is good though. All love is good and valuable and important. For example, we showed experimentally that touch releases oxytocin so I started hugging people instead of shaking hands. This earned me the nickname "Dr. Love." At first this was a bit embarrassing to me. But then I started to think, what better thing can I do on the planet but to give people love so now I'm happy to be Dr. Love.
TNH: When you witness another person's suffering, and mirror their feelings, you suffer too. Perhaps that's a reason why people sometimes avoid feeling empathy. On the other hand, loving-kindness always seems rewarding. Can you comment on the distinction between empathy and love?
Zak: Empathy and love both seem to be related to oxytocin. I think this is why we want to hear those sad love songs over and over. There is a soothing to sadness. Remember that when suffering moves us to engage with others then we get the pleasure and reduction of anxiety from the HOME system. Helping others is important to humans. I recall last time one of my daughters had the stomach flu and I stay up with her all night while she vomited and at one point she apologized to me. I told her I couldn't think of a more important thing to do than hold the bucket and be with her. It was her suffering that moved me to help her, even though I, too, suffered with her, I felt good that I could help her.
TNH: I recently heard the psychologist Roy Baumeister talk about how we have less willpower when our blood sugar is low. Does our ability to love also draw off physical resources of the body that might vary during the day? Do we love more on a full stomach?
Zak: Great question! Everything we do draws on our metabolic resources though oxytocin synthesis is metabolically cheap so we can't love too much. Actually, eating mildly stimulates oxytocin release so that's why we take dates (and hold meetings) at meals--it makes it easier to connect to someone.
TNH: From a purely biological perspective, are there any dangers of loving too much? Can you overuse this circuit in a way that harms your heath?
Zak: Actually, work in animals shows just the opposite. The more oxytocin is released, the lower the threshold for its release. In other words, the more we love, the more we can love. My research has shown that those who release the most oxytocin after being trusted are happier in their lives. They are happier because they have better relationships of all types: romantic, with family, they have more close friends, and are even kinder to strangers. We've also shown that oxytocin release improves the immune system by reducing stress. So, love freely!
TNH: The New Humanism is sponsored by the Harvard Humanist Chaplaincy. The chaplaincy also sponsors a mindfulness group that takes a secular approach to meditation. One thing we've done is loving-kindness meditation. Do you have any findings related to that practice?
Zak: We have recently studied loving kindness (metta) meditation and compared this to mindfulness meditation. This was for people who had never meditated before and received a month of training. Both kinds of meditation lead to greater altruism, but metta did this to a greater extent. Metta meditation was more valuable to those who received it than mindfulness meditation, and the metta group had a larger reduction in brain activity in regions associated with anxiety and self-focused attention than the mindfulness group did.
TNH: In loving-kindness practice, you spend a few minutes bringing to mind someone whom you love or who loves you. Once you have evoked feelings of love, you then bring to mind a person who you might not like too much. It seems that the feelings of love "spill over" and you feel warmth toward this other person. You write that the half-life of oxytocin is 3 minutes. Does lingering oxytocin account for one's ability to feel love toward an individual to whom you were previously indifferent or hostile?
Zak: The spillover from oxytocin is very likely causing this effect. A three-minute half-life means that you have an oxytocin "glow" for around 20 minutes. I think this is why metta is effective in changing they way we feel and behave.
TNH: So when you have an experience of connection--whether it's natural or in the case of metta meditation, you're summoning it up, and it causes oxytocin release—for the next 20 minutes you're going to be particularly nice to the next person who comes along, presumably?
Zak: Right. There is roughly a 20 minutes window in which once your brain has released oxytocin, we've shown in experiments that people are basically much nicer to each other, give much more to charity. They behave in ways that are very pro-social even with strangers.
TNH: People report that loving-kindness practice doesn't just change the way you feel about an adversary during the practice itself, but can actually transform your interaction when you meet that person in real life. That's clearly long beyond the expiration of the original empathy response. So what is going on there? Do you form an emotional memory during the original loving-kindness practice and then recall it when you actually meet the person in real life?
Zak: Oxytocin receptors live in areas of the brain associated with social memories (animals that cannot produce oxytocin get "social amnesia"). So, we are laying down memory tracks using oxytocin on who is safe, trustworthy, and kind. These memories are being rehearsed each time we have a positive interaction and so it can lead to us being kinder to more people more of the time. Practice is the key to activate this effect.
TNH: Can one make a habit of practicing loving-kindness, so that it seems to come naturally and automatically in your personal interactions? If so, does can the oxytocin circuit work below the level of conscious awareness?
Zak: Yes, for exactly the reasons I've just mentioned.
TNH: What do you think of the idea of unconditional love, that you feel the love and you don't feel a need for reciprocation? If it gets reciprocated, that's great, but a good way to spare yourself the crush that occurs when love is not requited is to feel unconditional love?
Zak: It's a much more mature approach, something that parents can do quite well, when your teenage son or daughter rejects you, and you realize that it's their hormones, their stress, and somewhere deep down, they probably do really love you. But think of when you're twenty and that unrequited love is the worst thing in the world and if that person does not reciprocate quickly, you're angry, mad, hurt, depressed. That's consistent with the prefrontal cortex, the newest part of the human brain, not fully wiring up till about thirty…. There is pretty good evidence its damps down wild emotional states. Once we're over thirty, it's a lot easier to put things in perspective. I think, love freely and don't worry so much about the return.
For readers, I want to make sure people don't feel bad if they don't feel they can love without any reciprocation, which is very difficult and takes a lot of perspective, maturity and probably prefrontal cortex training.
TNH: You're actually suggesting that a younger person may be at physical disadvantage in doing it?
Zak: Yes, absent mindfulness training or metta training where you're actually exercising the prefrontal cortex and learning in disciplined way to control how you're interacting with the world.
TNH: I do believe teaching people loving-kindness practice will help them be kinder, but I am cynical enough to think there are some "bad apples" out there and the person who comes to mind is Charles Manson, the notorious killer who took advantage of the 1967 "Summer of Love" in San Francisco to recruit people into his homicidal cult. You've actually found in your research that there are some people who have a very difficult time reciprocating empathy. What are your thoughts on how we can feel loving-kindness toward the "bad apples" without being exploited?
Zak: Psychopaths just don't feel the empathy, the love, and are permanently in selfish, survival mode. So I'm of two minds. One is this Buddhist ideal and in Christianity too, you try to value people who are difficult because they give you an opportunity to practice compassion …. But I sort of feel those people don't deserve our love and attention because they'll only use it to take advantage and to hurt… I hate to say anyone is unredeemable, because what if I'm wrong, what if I find someone I think someone is a psychopath, but really they were abused as a child? The safer thing to do is to try to love everybody unless you're being exploited.
TNH: You can have people who are not psychopaths, who are normal people who love others of their own ethnic group, say, so much that they're willing to harm people of another group. The question is, how do you create rapport among people who are different? From your research, it seems that oxytocin itself causes feedback that improves rapport.
Zak: Nobody really knows. But it is easer to build rapport one on one. We know this from lots of different things. Those commercials you see for the starving children in Africa, they almost always show one child. They don't show a bar graph of how many kids will die tomorrow if you don't send in ten bucks. It's that one on one interaction that induces a much stronger oxytocin stimulus rather than some sort of cognitive approach….
One of the potent inhibitors of oxytocin release is stress, and one of those stresses is survival stress…If your body is not facing survival stress, then you sort of have the luxury of connecting to others. That connection is always costly in time or resources and not everyone can do that. All of us don't do it all the time. As average incomes rises, there's a pretty strong gradient of better behavior occurring on average.
Steven Pinker makes a good case that literature develops tolerance, particularly fiction, getting inside someone's head. That's consistent to what I've been saying.