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.
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.
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.
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
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.
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."
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.
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.
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?
JC: Probably a mathematician.
MG: So not so far afield.
JC: Steph likes to help. I don’t. I like taking things apart.
Extended Interview
