Do Lonely People Have Different Brains?

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This holiday season is different than any we've experienced since the last pandemic in 1918. Most of us have not been able to get together with family and friends in person to eat, drink, talk, and celebrate. For many of us, especially those who are elderly or living alone. 2020 has been a lonely year, and a socially isolated holiday season makes this loneliness even more poignant.

Loneliness is a significant risk to both long-term physical and mental health, as has been shown in previous research. A new study by researchers at McGill University in Montreal, Canada sheds new light on how the brains of lonely people may differ from the brains of those who do not see themselves as lonely. This research highlights a particular network of the brain called the default mode network (DMN), which is active when we reflect on past events, plan, decipher the intentions of others, and anticipate the future.

Loneliness is a health risk

Loneliness is a serious health issue. Loneliness and social isolation can lead to cognitive decline in the elderly, as well as depression and other mental health issues. Loneliness is also a strong risk factor for illness and death, equivalent in size to obesity or smoking 15 cigarettes a day. It also is associated with some immune system issues.

Humans are social beings, and we are wired to connect with other people and feel a part of a tribe. Unfortunately, in modern society, communities are less stable and connected and an increasing number of people do not feel part of a community, neighborhood, religious, family, or friendship network. The elderly are particularly likely to be more isolated because of friends moving away or dying. Many do not have a daily routine that makes them feel a part of a social unit.

The study

The study by University of Montreal researchers used data from Biobank, an open-source database of more than 40,000 middle-aged and older adults in the UK. The researchers identified lonely people by their response to the question: " Do you often feel lonely?" (yes/no).

One limitation of this measure is that it was a single item and may not fully capture the nuanced nature of loneliness. The single-item measure of loneliness is a subjective assessment, rather than an objective measure of how many people were in their social networks.

Subjective measures are important because you can associate with many people but still not feel connected to them or accepted or included. Previous research has shown that lonely people have a concept of themselves that is more separate or further apart from their concepts of other people than non-lonely people. Lonely people often refer to themselves as being alone, unwanted, or socially undesirable. They may see themselves as excluded because of their inherent defectiveness. Perhaps they are too boring or offensive or awkward. Spending a lot of time by yourself does not, in itself, make you lonely. Some of us thrive on being alone. Rather, loneliness is being alone despite unmet needs for connection and social engagement. In this study, about 13 percent identified themselves as lonely.

How do the brains of lonely people differ?

This study used data from MRI scans of the brain. Results showed that the default mode network of the brain (DMN) was different in lonely people, compared to those not identifying as lonely. The different parts of the DMN are more strongly connected together in lonely people and the DMN has stronger connections with other brain networks controlling attention, vision, higher-order thinking, social perception, and so on. Grey matter volume was also higher in the DMNs of lonely people. The DMN is active when you reflect on past experience, imagine the future, worry about what is going to happen, or plan what you are going to do.

This finding of a more active and cohesive DMN is consistent with what we know about how lonely people perceive social interactions. Lonely people often have a cognitive bias toward negative information in social contexts. They are more likely to see themselves and others negatively. A negative brain bias can affect whom you engage with, how often you engage, how you behave, and how you experience things.

Another major finding was that of differences between lonely and not lonely people in the fornix — a cluster of nerve fibers that connects the DMN to the hippocampus for the memory center of the brain. In lonely people, the structure of these nerve fibers was better preserved than in the not lonely. This suggests a greater easier flow of information between the hippocampus and DMN in lonely people. Because the hippocampus stores memories of past experiences, it is possible that negative past experiences in social interactions (e.g., being bullied, criticized, or excluded) may bias information processing more in lonely people. They may be more likely to spend time remembering negative social experiences in order to ruminate about what they did wrong and why other people don't like them.

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Information processing biases in lonely people

Although the study didn't directly assess the effects of these brain structures on the thoughts or behavior of lonely people, we can interpret these brain findings in light of other research studies. Lonely people spend a great deal of time ruminating about negative social interactions or experiences of rejection or hostility from others. They may anticipate negative reactions from others, think that other people don't like them, and they may pay more attention to negative cues from others (e.g., noticing bored expressions more than interested expressions).

In other words, memories of past experiences of rejection or exclusion may influence their brains to anticipate future rejection or ruminate about how they messed up. Biased brain processing may lead lonely people to avoid social interactions in order to avoid a repeat of past negative experiences. When they do connect socially with others, they may be self-critical and vigilant for signs of rejection. Although this picture is consistent with what I see in clinical practice and some prior studies, we still need more research to definitively connect this pattern of cognitive bias with the brain findings.

What can you do?

If your self-esteem has suffered because of bullying, exclusion, being the subject of gossip, criticism, or other negative social experiences, what can you do to overcome the cycle of loneliness and sensitivity to rejection? Below are three suggestions.

Stay in the present moment

Notice when your brain is busy judging your own performance in social situations or thinking about how negatively others see you. Deliberately redirect your attention to what is actually happening in the present. Listen to what the other person is saying and engage your curiosity about the subject so that you can naturally reply with interest.

Stop avoiding

Try to overcome your tendency to avoid social situations or isolate yourself. This may be difficult to do with the COVID lockdown, but you can still engage outdoors or via Zoom. The more you isolate yourself with your own thoughts and ruminations, the less likely your DMN is to be changed by new, positive information. Try to keep an open mind and don't prejudge how social situations will play out.

Get feedback and practice new skills

Get feedback from other people about how you come across in social situations. Ask for positive feedback to overcome your negative bias and negative feedback to show you how you can improve. If you are awkward or anxious, write down what you want to say and practice in front of a mirror. The more you practice social skills, the better your performance will be.

Summary

In summary, brain research highlights that the DMN and fornix are different in lonely people. This is consistent with their bias towards negative social information. While avoidance makes things worse, engaging with others even if it's uncomfortable, keeping an open mind, and practicing new skills can go a long way towards more comfortable and rewarding social experiences.