Thursday, October 23, 2014

From Neuroscience's Perspective: Our Brains in Love and The Harmful Effects of Loneliness

This two-part interview with neuroscientists John and Stephanie Cacioppo (conducted by Marin Gazzaniga, daughter of Michael Gazzaniga, the well-known and highly respected neuroscientist) comes from Cafe, a cool online magazine. In the interview they discuss how the brain changes when it's in love, as well as the very negative impact of loneliness on the brain.

[For what it's worth, the image above came up on a search for "loneliness," but to me it feels like peace - but then, I am an introvert.]

Our Brains in Love: From Neuroscience's Perspective

What does a neuroscientist who studies loneliness have in common with a Ph.D. who studies love? For one, they share the same home, office and last name. In Part One of this two-part interview, John and Stephanie Cacioppo discuss how love helps you read minds, and whether you can experience desire without love.

What Qualifies Me to Talk Neuroscience?

I don’t claim to be a science writer; most have advanced degrees in their areas of expertise. But my father, Michael S. Gazzaniga, is well known in his field—one of the founders of cognitive neuroscience, and a pioneer in the theory of left and right hemisphere function. I grew up visiting his labs, and I have a basic comfort level with the vocabulary and methodology of neuroscience. One of the perks of being his daughter is that I can convince some of the world's leading neuroscientists to talk to me about their work. They will be patient with my simplistic questions—because some of them used to babysit me. 

He Wrote the Book on Loneliness; She Looks for Love in the Brain

My first call was to John and Stephanie Cacioppo. I met Stephanie when she was doing her post-doctorate work with Scott Grafton at the SAGE Center for the Study of the Mind at the University of California, Santa Barbara (which is run by my father). She helped me with a plot point in a play I was writing, in which my main character is in an fMRI scanner and a certain area of her brain lights up, which suggests she is in love. My question for Stephanie was: Is this possible? Is there a love area of the brain? Could our brains know we are in love before we do?  The answer was a qualified "yes."

Now, years later, Stephanie has fallen in love and married one of the founders of Social Neuroscience, John Cacioppo. Apparently their brains lit up when they met at a conference. They are a rom-com "meet cute." He wrote the book on loneliness. Literally. And she studies love.

© Stephanie Cacioppo
They spoke to me from their home office, sharing the phone, answering each others’ questions, and praising each others’ work. If they weren’t the researchers, they could be subjects for Stephanie’s studies on love relationships.

How Love Makes You a Mind Reader

MG: Stephanie, can you briefly describe your recent research?

SC: I try to better understand the role of the mirror neuron system in social interactions, and how social interactions, specifically with significant others, can be beneficial and detrimental to our mental and physical health.

(A side note: Mirror neurons were first discovered in monkeys, and later in humans. They are brain cells that are activated when you perform an action, and when you observe others doing the same action—hence the "mirror" name. The exact function of the neurons is still debated, but many believe they are associated with empathy.)

MG: Can you give an example?

SC: I’m interested in how a bond with your spouse, for instance, can make you think better, faster and make you healthier. In terms of thinking faster, one model I’m using is that of embodied cognition. How your social connection with your spouse can help you understand his intention very quickly, even before he’s finished his action. Is that clear?

MG: Can you give me an example of an experiment you do to look at that?

SC: Typically, we ask participants to watch different agents (a stranger, a friend, a family member, a beloved spouse) perform different actions (grasp a cup of coffee, hold a gun, toss a tennis ball in the air) with different intentions (meaningful, harmless, kind, etc.), and we ask the participants to guess what the agents’ intentions are, before they complete the actions. The participants are in an fMRI and we measure their brain activity while they do these tasks. Research suggests the more you feel "in tune" or "bonded" with someone, the faster you can anticipate their intentions. 

MG: What have you found about how love relationships impact this ability to predict behavior?

SC: When it comes to couples, theories of simulation and embodied cognition are in line with a model that is well-known in relationship science: The model of self-expansion. This model suggests that you fall in love with someone to expand yourself or to include the other’s attributes to make you a better person. Altogether, these theories suggest that the more in tune/in love you are with someone, the more time you spend with that someone, the more motor familiarity with them you acquire (unconsciously or not), the more your brain can encode their actions, the more your brain can then re-activate their actions by simple observation of the first step of a movement, and the faster you can understand their actions. In other words, the more you have a joint representation of yourself and the other person, the faster your mirror neuron system will be activated and the faster you can understand him or her.

MG: So somehow with our significant others we become more in tune with the motor processing cues. So, I can tell my husband is reaching for his car keys, say, rather than the mail, before he picks them up.

SC: Yes. And it doesn’t need to be conscious. That’s the beauty of it. It is largely a spontaneous and automatic process.

The Difference between Love and Desire

(At this point, John interrupts.)

JC: Tell her about the—

SC: Go ahead.

JC: (laughs) Steph’s work is brilliant. She’s looked at all of the fMRI studies of love and sexual desire and finds some overlapping brain regions but clearly some very different regions of the brain involved, as well. Importantly, love or desire isn’t represented as a spot in the brain. Each is the result of the collaboration of a set of neural regions operating on perhaps the same input to produce different inferences about and responses to that person. For instance, one distinction is in the insula – a long narrow nucleus on both sides of your head. There’s a front part (anterior) and a back part (posterior), and the distinctions within the insula are that the anterior regions are associated with more abstract representations and thought, and more temporal flexibility (for example, future orientation, mental time travel), whereas the posterior regions are associated with the present sensory, visceral and motoric inputs one is experiencing. This functional organization (concrete representations and operations in the back, abstract representations and operations in the front) is pretty typical of the brain generally.

MG: Uh huh. (At this point I felt my own brain getting a little overloaded.)

JC: What Stephanie found in the fMRI studies is that the back part of the insula, the posterior insula, is associated with desire whereas the front is associated with love. Now from that, Steph has developed a model of love and desire where both can actually occur together but, of course, need not do so. When both are active, the person is more likely to not only love someone but also desire that person.

Can You Love Someone but Not Desire Him? Or Vice Versa?

JC: Imaging research is correlational, though. It tells you these areas are associated, but it doesn’t tell you what they are doing. So the insula is an area of the brain where it’s hard to find lesion patients; because it’s not a richly vascularized region, strokes that compromised just a single part of the insula are uncommon.

(An aside: John spoke earlier about the need to study the "hole in the brain." That means looking for patients with a lesion (injury) to a specific part of the brain in order to learn more about what that area actually does—to see if the damaged area disrupts the behavior. In other words, if your anterior insula is damaged, do you lose the ability to love?)

JC: Steph found such a patient in South America. The front of the insula was damaged. She tested that patient for tasks she has used in her behavioral and neuroimaging research on love and desire. And she also tested other South American men to make sure that it wasn’t a cultural difference. The South American men were like the US men in how they responded to the tasks. Importantly, she also found that the patient whose anterior insula was damaged had trouble with tasks when it involved making judgments about love, but not when it involved making judgments about desire (photos they were looking at). That’s brilliant work showing it’s not just correlational. There’s something causal about what the anterior insula contributes to love. Stephanie is still looking for a patient with a lesion in the posterior insula. But her combination of neuroimaging and lesion research illustrates the kind of rigor that characterizes her research. I just love her mind.

SC: And I love his mind!

MG: I’m curious, what kind of task do you come up with that distinguishes between love and desire?

SC: So we have different tasks. One of them is to present images of single individuals, fully clothed, and we use the same exact stimuli for the love and the desire task. But the instruction is different. For the same set of pictures, the participants are being asked if the person is love material. And in another block, we present the same pictures in different order and ask if they could feel sexual desire for them. And the participants are asked to press keys to tell us their response and we analyze their brain activity based on their behavioral response rather than on the category of the stimuli. During previous studies, researchers have tended to categorize the stimuli ahead of time as being desirable or loveable. But someone who is desirable for you may not be for me. So we thought that it was very important to analyze the brain activity based on the participant's response rather than the experimenters' categorization.

How a Doctor of Love Can Help

MG: You mentioned that one of the lessons you learned from Scott Grafton and my father was to always ask the question, "And so what?" What is the "so what" of your research on love?

SC: People wonder why you need a Ph.D. to study love. A lot of people have a lot to say about this topic and they all think they know what love is and why we fall in love, and actually they don’t. We need to understand the brain in love, scientifically. And to bring the psychological model and biologic sciences to this field.  By breaking down love with different scientific and mathematical approaches we can really try to reconstruct it and better understand it in healthy couples and patients who have neuropsychiatric issues with love relationships. We can try to treat jealousy, people with obsessive-compulsive disorders—stalking—autism, patients who have social disorders and difficulty relating to others. By bringing science into this so-called soft science we can help patients in their early life.

NEXT….In Part Two of this series, John explains the brain science of loneliness.
 photo: S. Cacioppo. Modified from NeuroImage, 2008; Vol. 43, no. 2

* * * * *

The Harmful Effects of Loneliness

In Part 1 of this interview, married neuroscientists John and Stephanie Cacioppo discussed her research on love. Here, John explains his research and some paradoxical behaviors of the lonely.

MG: You are one of the founders of social neuroscience. Can you explain what that is?

JC:  The premise of social neuroscience is complementary to cognitive neuroscience – but distinct. In cognitive neuroscience you look at the brain as if it were a computer. The metaphor stimulates a number of questions. For instance, language is viewed as a way of representing information in the brain. So you ask: What is that representational system? Where is the encoding and decoding? What types of storage and memory systems exist? In social neuroscience, the appropriate metaphor is the cell phone. Brains are viewed as mobile, broadband-connected computing devices. This metaphor raises different questions, such as: Where’s the wifi card? What’s the communication protocol? Language is seen as one of the ways these devices are linked, rather than a way to represent information within the device. Neither cognitive nor social neuroscience is "correct." They are distinct and complementary perspectives on the human brain. 

Why we need grandchildren to survive

MG: So what is the focus of your work?

JC: I’ve been interested in a combination of social and biological perspectives on the human brain for years now. What struck me as interesting about social in the first place was that social species, by definition, create super-organismal structures. These structures evolved hand in hand with neural, hormonal, cellular, and genetic mechanisms because they promote behavior that foster survival, reproduction, and care for offspring sufficiently that they reproduce. For mammals, whose offspring are dependent on parental care, it’s not your ability to reproduce that determines your genetic legacy but your ability to have grandchildren. If you reproduce a great deal but in conditions where there is no care for those offspring, then they perish during infancy, leaving you with no genetic legacy. So one interesting question is, What are the biological mechanisms that help us survive as a social species? The way I’ve been investigating this question for the past twenty years is to determine what happens when an individual is absent social connections. 

MG: Loneliness.

JC: Yes. So you see it’s actually a complement to what Stephanie studies. 

MG: She studies love - how people create deep connections - and you study what happens when they feel isolated.

JC: Yes, the reason I took that approach is very straightforward. If I want to understand what a gene does, I create an animal model where I can compare the responses from an animal that has that gene and an animal that does not. If I want to understand what the orbital frontal cortex does, I look at Phineas Gage before and after his orbital frontal cortex was obliterated. It’s not that I’m interested in the hole in Gage’s brain; I’m interested in what happens before and after that hole existed. Similarly, if I want to know what the effects of meaningful social connections are, I can compare individuals who feel socially connected with those who feel absent meaningful social connections – that is, individuals who feel lonely.

What Robin Williams knew about loneliness

JC: We’ve been doing experiments and longitudinal research on loneliness to determine the effects of loneliness on behavior, brain function, autonomic and neuroendocrine activity, sleep, and gene function. Fairly quickly we found that it isn’t the objective presence or absence of people, it’s whether you feel isolated. The brain is the key organ for forming, monitoring, maintaining, repairing, and replacing salutary connections with others, so the presence of others in many cases is less important than whether one feels connected or isolated. Stephanie gave me a quote from Robin Williams, from 2009. He captured this point better than many scientists: "I used to think the worst thing in life was to end up all alone. It’s not. The worst thing in life is to end up with people that make you feel all alone."

We’ve found that chronic loneliness is associated with early morbidity and mortality as well as a number of psychological disorders. For instance, our longitudinal and experimental research suggests that loneliness increases depressive symptoms. Loneliness also leads to heightened sympathetic tonus of the vasculature.

MG:  What does that mean?

JC:  Loneliness can lead to higher blood pressure. It also disrupts sleep due to an increased number of micro-awakenings over the course of the night. These effects are independent of the amount of sleep, or whether or not you’re actually sleeping with someone. We’ve seen this effect in studies of undergraduates and in the Hutterites (a communal population), and we’ve seen loneliness predict less salubrious sleep longitudinally. If you feel lonely tonight, you are likely to have more micro-awakenings across the course of the night. 

MG: Why is that?

JC: We have an evolutionary theory to account for these findings. If it’s dangerous to fend off wild beasts all day with a stick, imagine how dangerous it is to lay that stick down at night and sleep when predators are out and you don’t have a safe social surround. Going to sleep feeling isolated puts the brain into a state of alert for threats to promote self-preservation. The disruption of sleep has been seen in an experimentally isolated social animal, as well. 

MG: How do you determine the difference between someone who is feeling lonely vs. not feeling lonely? Is it just self-reported?

JC: We have a couple different ways. We have a monkey model and we are developing a rodent model of loneliness. In both of these models, we focus on the behavior of the animals to define loneliness. When working with people, however, we typically use a set of questions to measure loneliness. We don’t ask, "Do you feel lonely?" because men, in particular, tend to under-report. But there are other questions we can ask that relate to loneliness. If you ask, "Do you feel lonely?" there’s a bit of defensiveness that is aroused. But if you ask, "Do you feel socially isolated?" "Do you have others in whom you confide?" Then you start to get a more accurate picture of the extent to which they feel socially connected or isolated. 

Why loneliness can make you negative

JC: You know what the Stroop test is, right?

MG: Uh…I know the name. But…remind me?

JC: Stroop developed a test in which you show people the names of colors, but they appear in an incongruent color or ink, such as the word "blue" printed in red.

MG: Yes, yes.

JC: In the Stroop task, you ask a participant to identify what color the ink is. To people’s surprise, this is a difficult task because, whether they want to or not, people automatically read the words. Because you’ve read "blue" but it’s written in red, it takes you longer to say "red." And in fact often you make an error and say, "blue."

MG: Right.

JC: The Stroop task illustrates how information can be processed by the brain even when we did not intend to do so and are unaware of having done so. We used a version of this task to investigate how individuals who felt lonely or non-lonely preattentively (automatically) processed positive and negative social and nonsocial information. We presented social and nonsocial words in different colors and instructed participants to identify the color of ink in which the word was presented.

MG: What’s a social or nonsocial word?

JC: A negative nonsocial word is "vomit." A negative social word is "reject." As you can see, both are very negative words. What we found is that the lonelier you feel, the longer it takes to name the color of the negative social words. 

MG: Huh.

John can tell I’m not completely following…

JC: That’s evidence that if you feel lonely, your brain is especially paying attention to negative social stimuli because we did not find this interference effect when we contrasted positive social and positive nonsocial words. 

So, the idea is, you aren’t just being a Negative Nancy, you are actually on the lookout for things—or more specifically, people—that could hurt you because there’s no one around you feel would protect you.

How depression may actually be a way to connect

JC: Whether a fish or a herd animal on the social perimeter, the attack of another member is not only sad but also a threat to your survival. So the brain is more likely to focus on self-preservation than on the welfare of others. In fish, for example, an attack increases the tendency for each of the fish to swim to the middle (as far from the social perimeter as possible). We see similar behavior in herd animals. And we see something similar in the brains of humans. In brain imaging studies we have also found that the lonelier you are, the less brain activation found in the temporal parietal junction when viewing a negative social scene—for example, a photo of someone being hurt. Activation of the temporal parietal junction occurs when you take the perspective of another person, empathize with that person, or think about what they are thinking or experiencing. The fact that loneliness is related to less activation of this brain region is interpretable in terms of the lonely brain emphasizing self-preservation rather than concern for others.

The interesting part of this story is that people do not have conscious access to what their brain is doing. You don’t know your brain is in self-preservation mode because the brain was selected to do this long before humans walked the earth. The absence of accurate insight into what our brains are doing increases the likelihood that lonely individuals engage in self-protective—but paradoxically self-defeating—behavior. They are motivated to reconnect, but they engage in defensive, sometimes downright prickly behavior. When you feel lonely, you are more likely to be negative and disagreeable. Although this seems dysfunctional, it actually can promote survival in a potentially hostile social environment while an individual seeks to reconnect. We actually think that the depressive postures, vocalizations, and behavior that result from loneliness is adaptive—specifically, they may be ways to connect at a distance. I don’t have to push my way back into the group. I can sit there and cry, and look very sad, and if there are others in the setting who are willing to reconnect they are more likely to do so. If you’ve ever put your child in "time-out," you know what a strong force the child’s sadness can exert on you. These depressive behaviors, then, may have the positive effect of being a safe way to reconnect when you’ve been socially isolated. 

The paradox of loneliness

JC: I didn’t even mention all of the biologic effects that have been seen in human and animal studies. The lonelier you feel at the end of a day, the greater rise in cortisol we see the next morning. We see a change in gene expression, one of the most robust being increased inflammatory responses. In animal studies, an animal who is isolated from others and subjected to an experimental stroke shows three times greater brain cell death than normally housed animals who are subjected to the same experimental stroke. The differences in cell death appear to be due to differences in neuro-inflammation. Although there is more to do, these findings appear to be fitting together to tell an interesting story of how loneliness can lead to earlier dementia and earlier mortality through a variety of specific biologic processes which, from an evolutionary perspective, occur to increase your likelihood of short-term survival when you find yourself on the social perimeter.

Final Pop Quiz

Stephanie has rejoined the conversation, and I decide to let them go with an easy question. 

MG: If you weren’t neuroscientists what would you be?

Long pause. 

JC: Probably a mathematician.

MG: So not so far afield.

SC: Same. A physician.

JC: Steph likes to help. I don’t. I like taking things apart.

MG: Sounds like you’re doing exactly like what you want to be doing.

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