Thursday, September 11, 2014

Social Pain: A Conversation with Naomi Eisenberger

Here is a new Conversations at Edge with Naomi Eisenberger, a professor in the Social Psychology program at the University of California, Los Angeles. She is director of the Social and Affective Neuroscience laboratory as well as co-director of the Social Cognitive Neuroscience Laboratory.

Dr. Eisenberger was featured in an earlier Conversations at Edge on Why Rejection Hurts [7.6.11].

Social Pain

A Conversation with Naomi Eisenberger [9.10.14]
Topic: Conversations



Naomi Eisenberger's Edge Bio Page


The kinds of questions that I'm interested in have to do with the feelings that come up in our closest social relationships. I've been on both sides of this equation, the negative side and the positive side. I've been very curious about both the painful feelings that we have when we lose our closest social relationships or we feel disconnected from others, as well as the pleasurable feelings that we have when we feel close and connected to those that we love. One of the things that we've been exploring in my Lab at UCLA is where those feelings come from. One way that we've been doing this is by turning to the brain to try to understand those feelings of social closeness or social distance.

We started off on the negative side. I started off with this question of: why do people talk about feeling hurt by social rejection? Why do they talk about the pain that comes up when they feel left out or excluded? It's a very palpable experience. Most people, if you ask them to think back to some very painful event in their life, instead of bringing up something that involves a broken bone they’ll often bring up an experience that involves losing a social relationship or being rejected. We all have these memories of being left out on the school playground or fears of being left out on the school playground. So I was very curious. Where do those fears and where do those feelings come from?

(29:23 minutes)

To explore this we essentially created a setting, created a situation that we could expose our subjects to, see what's going on emotionally when people feel rejected, and then what's going on in their brains when they experience this state. In this first study we brought people in to the fMRI scanner and had them play a virtual ball tossing game with two other supposed subjects. They thought they were playing this interactive game together. It turns out they weren't actually playing with two other people, but they didn’t know this yet. What happened during this game is that these two computer players stopped throwing the ball to our subjects so we could look at the brain and see what's going on for these individuals, what's going on in their brains when they're being rejected compared to when they're being included in the game.

What we found here was really interesting, that some of the same regions of the brain that process the painful experience—the distressing component of physical pain—are the same regions that seem to activate when people feel socially excluded. It gives some weight to this idea that rejection really can be painful. The same regions that process the unpleasantness of physical pain process the pain of social exclusion. This got us thinking about the overlap, the possible shared neural circuitry underlying physical and social pain. Maybe the same regions that process physical pain have been borrowed over the course of our evolutionary history to process social pain.

When you think about us as a social species, this actually makes quite a lot of sense. We rely on people, we need to be close to others, especially early on for protection, for care, for nourishment. To the extent that being separated from a caregiver or from a close other is such a threat to our survival, then actually feeling this pain signal when we're separated may be an adaptive way to prevent being socially separated.

We've gone on to explore some of this shared circuitry. We've tested a few ideas that come from it. One idea is that if physical pain and social pain really rely on some of the same neural regions, then one consequence of this is that people who tend to be more sensitive to physical pain should also tend to be more sensitive to social pain, and we've been able to show this in a few studies. We found that subjects who, at baseline, are naturally more sensitive to physical pain are the ones who later on report feeling more rejected by the same virtual ball tossing game where they get excluded.

We've also seen some genetic evidence for this. We find that people who carry the more rare version of the mu-opioid gene, which is linked to a greater sensitivity to physical pain (opioids are potent painkillers), are individuals who have a genetic disposition to be more sensitive to physical pain. These are the same individuals who report feeling more upset by social rejection; they show greater pain related neural activity in response to social exclusion.

A second consequence of this overlap that we've been exploring is whether certain factors that alter one kind of pain can alter the other in a similar manner, and probably one of the most interesting studies we've done is one where we looked at acetaminophen. We typically think of acetaminophen as a physical painkiller. In this particular study, we randomly assigned people to either take it everyday for two weeks or take a placebo everyday for two weeks. Instead of measuring their physical pain, we measured their social pain. We asked them each evening to rate their hurt feelings. We also then brought them in at the end of a separate study to look at their neural sensitivity to social exclusion. What we found is that the people who were taking acetaminophen reported less hurt feelings than people who were taking placebo, and they showed less pain related activity to social exclusion, just as a function of taking acetaminophen. We see this crossover effect in some ways, that this agent, which known to reduce physical pain, also seems to affect social pain.

Those are some of the things that we've been looking at on the more negative side of social experience. I've also become very interested recently in exploring the positive feelings that come from our social connections, and these have probably been the trickiest to really emulate in the scanning environment. It's easy to put somebody into a negative state when they're laying alone in a contained structure. It's harder to really get people to feel connected to their close others when they're all alone in the dark in the fMRI scanner.

In the same way that we've been curious about some of the neural substrates that might have been borrowed to support our experience of social pain, we've also been interested in what neural substrates might have been borrowed to support those pleasurable, warm feelings that we have when we're feeling connected.

One kind of substrate that we've been really interested in are those neural substrates that process temperature. The reason for that is because a lot of times when we talk about our feelings of closeness or connection, we talk about warmth. We talk about somebody making us feel warmhearted, we talk about our warm feelings toward somebody, so we wondered whether some of the same mechanisms that process warmth—that lead us to feel sort of pleasantly warm about a physical object—are the same mechanisms that lead us to feel warm about somebody else.

In one study we brought people into the scanner, and we wanted, again, to look at overlapping neural activity between physical warmth and social warmth. To look at physical warmth, we have them holding onto one of those warm packs that athletes will use where they crack them open and shake them up and it produces warmth in the packet. We scanned people when they were holding warm packs and a neutral temperature pack, and we also scanned them while they were experiencing social warmth. To do this we had the participants’ family members and friends, before the scanning session, write email messages to the participants. These were loving, tender messages that the subjects saw for the first time when they were in the fMRI scanner. We looked at what the brain was doing when subjects were viewing these socially warm images and whether or not it overlapped with what was going on when they were feeling these physically warm packs.

What we found, first just in terms of their self reports, not surprisingly, people felt more warm when they were holding the packs. They also reported feeling more warm when they were reading those nice messages. What was also interesting is that subjects not only reported feeling more connected when they were reading those messages, they also strangely enough reported feeling more connected when they were simply holding those warm packs.

The last thing that we saw was neural activity in reward-related regions during both tasks, and it turned out that there were several regions that showed overlapping neural activity. Some of the same regions that are processing physical warmth and the pleasantness of that sensory experience were the same ones processing the social warmth that people are getting from these loving messages.

Another line of research on the positive side is our research exploring the neural substrates of support-giving. Essentially there's been a lot of work showing that social relationships are critical for health. Most of the time, though, when people ask why social support is critical for health they assume that it's because of all the support that we get from others. Less often have people really looked at the support that people give to others. So when you help out a friend, or you take care of somebody, or you offer to do a favor for a family member, this is not considered support really because it's not helping us. We're doing things for other people. But this actually may be a key ingredient helping to explain some of the relationship between social support and better health.

We've been interested in some of the neural underpinnings of this particular state. So we ran a study where we brought in couples, and the female member of the couple was in the fMRI scanner, and essentially we scanned her brain while she was providing support to her partner. Her partner stood just outside of the fMRI scanner, and on certain trials he received electric shock. The female could support him on some trials by holding his arm as he went through this experience. This was a form of giving support to help somebody going through something negative or something painful.

There were two main findings here. The first is that we saw reward-related activity when people were providing support to somebody else. Some people say this is not terribly surprising. We all know that something about support-giving feels good. Some people might say that seems surprising because we're actually doing work to help somebody else, but we did see reward-related activity. We actually saw more reward-related activity when the females were touching their partners when they were getting pain—when they were support-giving—compared to when they were just touching their partners and their partners weren't getting pain. It seems like maybe there was something more rewarding about being able to provide support than just being able to be in physical contact with your partner when they're not going through anything negative.

The last interesting finding was that the females who showed more reward-related activity when they were support-giving were also the ones who showed less activity in the amygdala. This is a region that's involved in a lot of different things, but one of the things that it's involved in is processing threat. People who showed more reward-related activity that were involved in support-giving seemed to be showing less threat-related activity

If you look into animal work and if you think about the evolutionary aspects of this, it makes some sense. The idea here is that to the extent that we're in a caregiving situation, we need to remain calm. There may be some circuitry in place that turns down our own threat sensitivity so that we can engage in adaptive caregiving towards others. There may be something about caregiving that actually turns down our own internal stress level so that we can engage and provide adaptive help to others.
We've been trying to build on this and to look at some of the health consequences of support-giving. Is there something about support-giving that's actually stress reducing for the person who's giving the support? Not just for the person who's receiving it, which is what's typically been looked at, but for the person who's doing the helping. We have some preliminary data where people write a helpful note to a friend in need. After doing so, they go through a stress task. Those people that wrote the helpful note, as opposed to people who wrote just a control note, actually showed a calmer physiological profile to the stress task. They were showing less of a heart rate increase, less of a blood pressure increase, just as a function of writing this helpful message to a friend.

~ ~
I've always honestly felt a bit like a mutt in terms of the fields that have influenced me. I would call myself now a social neuroscientist, but I was trained as a social psychologist with probably a large influence from health psychology as well. Unlike most social psychologists, I tend to read a lot more animal work, and that's probably from health psychology, which borrows a lot from animal models of disease and how different kinds of social environments can affect health outcomes. I don't think it's a field, but people who have studied social relationships using animal models, as well as human models, have also greatly influenced me.

Individuals who have influenced me include Harry Harlow, John Bowlby, and Jaak Panksepp—people who have focused on what makes up the glue that binds people together. You have Harry Harlow looking at very basic attachment processes...what does the monkey prefer? Does he prefer the food or does he prefer the warmth, or the softness? You have people like John Bowlby who's trying to chart out a mechanistic way for understanding attachment, a child’s attachment to its mother. Then you have people like Panksepp, who use animal models to understand basic motivational systems like love, attachment, rage, caregiving. Probably the central theme is people focused on social relationships, and not just romantic relationships.

There's a whole wing of social psychology that focuses on romantic relationships, and in some ways that's why I never consider myself a relationship researcher. I'm interested in more than just the romance. I'm interested in the friendships, I'm interested in the parent/child relationships, all of that. I've been probably more influenced by the folks who’ve studied social connection from humans to animals.                                       

I think romance is interesting and a lot of people study romance. There's a lot of other meaningful types of relationships out there that people, for some reason, seem to be less interested in. So when I think about the warm feelings that I have for my employees or my close friends or my son, I want to know where those come from.                 

~ ~
How do I know what I'm doing makes a difference? I have two answers. Some of my research makes a difference because it reveals something to people that they probably already knew but maybe were afraid to believe. When I think of the work on social pain, and showing that some of the same neural regions that are involved in physical pain are involved in social pain, that can be very validating for people. For anyone who's felt the pain of losing somebody or who's felt the hurt feelings that come from being ostracized or bullied, there's something very validating in seeing this scientific work that shows it's not just in our head. It is in our head because it's in our brain. It's not just in our head. There is something biological going on that's interpreting the pain of social rejection as something that really is a painful experience.

There is something inherently interesting about figuring out how people work, figuring out where these warm feelings come from, and I'm not sure in the end if it will help anyone. That line of research is almost meant to just understand these things and maybe not meant necessarily to help people in the end.                 

I was the kind of person that always wanted to know what I wanted to do, but I never did, and I happened upon science in a way. I met a mentor who was gracious enough to take me on. We did a project together, and I found something new, and literally it was that excitement of discovering something for the first time that led me to want to be a scientist.

This still drives me to this day, this moment of discovering something new about human experience that we didn’t know before, the "Ah-ha!" moments. That's what reinforces things, and perhaps that's a selfish reason to pursue science, but for me that's certainly part of it, that feeling of discovering something new.

~ ~
I got my Bachelor’s of Science at UCLA. I majored in psychobiology. It was there that I got my first taste of research, so I wound up doing an Honors Thesis with Margaret Kemeny, who's a health psychologist and also a psychoneuroimmunologist. Because of our work together I think I realized I really wanted to do science. I really wanted to be able to ask questions about human nature, about human experience, and then use the data to answer those questions. After finishing my Bachelor’s, I went to UCLA and got a Ph.D. there. I worked with Matt Lieberman (now my husband), with Shelley Taylor and with Shelly Gable. And I think at the time when I was in my second or third year of graduate school I was introduced by Matt Lieberman to this new area of science called social neuroscience.            
Before that I was probably more of a health psychologist. I was very interested in why social ties are so important for health, and there were all of these fabulous demonstrations of people who have more friends live longer and they are less likely to get sick. But I always felt like there was something missing with those models, and to me that was what's going on in the mind that translates the social world into whatever happens downstream in the body.              
I became very interested in social neuroscience as a way to connect that outer social world with the inner workings of the body to try to better understand some of the links between social issues and health. I took whatever classes I could, talked with whoever I could to learn all these techniques of social neuroscience. It was during that time that I, with Matt, did the study on social pain, looking at Cyberball, looking at people getting excluded in the scanner. My work built from there, continuing to look at that idea that physical and social pain overlap.           
In some ways I veered off to get training in social neuroscience. During my post-doc I came back to health again. So during my post-doc I worked with Michael Irwin who's a psychoneuroimmunologist, and here I did something pretty different than what I did before. I ran a pretty involved study where we injected people with an agent that triggers an inflammatory response to look at how that inflammatory response affects people emotionally and affects people socially and also what's going on neurally as a function of that.   

~ ~
I have two main thoughts about differences between males and females when it comes to academics. When I was in graduate school I never thought about gender differences in how I was treated versus how anyone else was treated. It wasn’t until I became an assistant professor tha I started to notice things. It was subtle things, like I felt when a male colleague presented on my data they didn’t get as many questions. When I presented on my data there were a lot more questions. I don’t mean questions about clarity, questions to clarify. I mean doubtful questions, like, "I don’t believe what you're saying." Those kinds of questions. I've spoken with other female colleagues who have said the same thing. If she gives the exact same lecture as her husband to a class of students, she finds that she gets a lot more pushback than her husband.

There's also social networking things. Matt talks to other males, I talk to other females. The males that he talks to, because I guess they're males, tend to be in more powerful positions. It's oftentimes males who are department chairs. So it's Matt that's talking about jobs, about people moving, and orchestrating things. He's the one who's networking and pushing for positions in different places.

That's one difference. Another thing that I've noticed, I've seen more of this in my students, is that the way that science is done is more male friendly. This is my opinion, so some people may disagree with this, but I have a lot of female students, and when they go to conferences and give talks and people ask them questions that are challenging, that are maybe mean spirited, it makes them want to disengage. Sometimes, for male students, they see this as an opportunity to engage, to fight's fun to argue. I’ll watch two males fight it out over some scientific question and think, "Oh my God, they're never going to speak to each other again," and meanwhile, they're having a really fun time. So there's something accepted about the way science happens that's a bit more male-oriented than female-oriented, in terms of its confrontational aspects.             

The last thought that comes to mind is that I've often wondered if females are less interested—at least some females—in self-promoting. There is maybe something uncomfortable about this kind of activity, or that they're just less interested, that it's not as important to them to get their message out, to be heard by a lot of people, and that's certainly something that I've dealt with myself. I like to do my science. I like to discover things. I like for other people to know about it, but do I want to go out and have speaking gigs all the time and get in front of audiences? Something about that makes me uncomfortable. I don't know if that's a "me" thing or if that's a female thing. "Me" and female are confounded so I can't really pull those two things apart.                                                                          
Post a Comment