In recent years, about one-in-two adults in America reported experiencing loneliness.

The mortality impact of being socially disconnected is similar to that caused by smoking up to 15 cigarettes a day.

Loneliness and social isolation increase the risk for premature death by 26% and 29% respectively.


These troubling statistics come from a 2023 report from the office of the U.S. Surgeon General titled “Our Epidemic of Loneliness and Isolation: The U.S. Surgeon General’s Advisory on the Healing Effects of Social Connection and Community.”

The report details the harmful consequences of a too-common challenge: loneliness. But it’s not all doom and gloom. The report also outlines how to build more connected lives through social connection and community.

Connection with others isn’t just something that’s nice to have, or simply an antidote to loneliness. It’s actually hardwired in us – we are biologically wired to connect with those around us. That’s right, the human brain is designed to be social. But what does that mean? And how exactly does it work? Let’s take a science lesson and dive into the social brain.

Why Do We Have a Social Brain?

Humans are born well before the brain is fully developed. This is simply a matter of logistics. A fully developed human brain would be too big to fit through the birth canal. At birth, the brain is around a quarter of the size of an adult brain, and only the lower part of the brain is fully developed.

Of course, we know that humans need certain things to stay alive, like food, water, oxygen and shelter. But a newborn baby is incapable of acquiring most of these basic needs on their own. Essentially, humans are rendered helpless for the first several years of life and are entirely dependent on others to meet our needs. It is quite literally a matter of survival – human connection is just as much a basic need as water. Throughout childhood, and even into adulthood, we continue to rely on others to meet our needs. The need for human connection that allows us to survive doesn’t ever go away, and the brain is designed accordingly.

The social experiences we have as babies can shape our social relationships for the rest of our lives. To learn more about the science behind these early human connections, check out these posts on attachment.

The Science of the Social Brain

Each part of our complex brain serves a specific function. For example, the amygdala is our emotional center of the brain and is responsible for the fight, flight or freeze response. The hippocampus controls our memories. The prefrontal cortex controls our logic and reason. But the social part of our lives is not isolated to one specific part. In fact, many regions of the brain support our social behavior and are activated when we engage in social interactions. This underscores just how integral social connection is to being human.

But even though there’s not one piece of the brain that is the social hub, there are many things happening in the brain that drive us to be more social. Let’s look at three.

The Medial Prefrontal Cortex

The prefrontal cortex, aka PFC (remember, that’s the logic and reasoning part of the brain that isn’t fully developed until our mid-20s) is broken down into two parts: the medial PFC (mPFC) and the lateral PFC (lPFC). The lPFC is generally associated with motor control and sensory processing, while the mPFC is generally related to emotional processing, memory and higher-order thinking. It’s this mPFC that is linked to social skills.

When we engage in a social interaction with another human, the mPFC lights up. Its job is to analyze other people’s facial expressions, tone of voice and body language. It helps us make sense of another person’s feelings and intentions.

Newer research on the mPFC shows that even newborn babies have engagement in this area when engaged in social situations. In one study, researchers showed 9- to 12-month old infants videos of their own mother and of a female stranger smiling at them. The mPFC was activated for both but had higher activation for the video of their mother. Researchers also determined that the mother had a similar mPFC response, indicating that these social encounters are mutually engaging for both parties. Similar research has been done on babies for studying voices, eye contact, and the use of the child’s name. This emerging research shows that even very young children are wired for social connection.  

The Reward System

You might have guessed from the name… the reward system of the brain is the part that, well, offers rewards. It is designed to push us towards activities that are pleasurable and/or helpful for our survival and lead us away from activities that are harmful. And the reward? Dopamine – a feel-good neurotransmitter that is released and serves as a pick-me-up for the brain and body.

Here is an example. It’s that mid-afternoon lull, and you’re hungry. You dig through your bag and find a granola bar. Your brain receives the information about the availability of a tasty snack, your hippocampus remembers having eaten this snack before – and remembers that it is tasty. Here’s where dopamine starts traveling along the mid-brain pathways, communicating along the way with the amygdala and the hippocampus. This activates positive feelings and helps develop or reinforce memories that will tell us to repeat this activity next time we are hungry. These pathways ultimately deliver dopamine to the frontal lobes, where reasoning, motivation and critical thinking take place. Dopamine in this area allows us to become conscious of the reward we are experiencing.  

Now, we used a granola bar as an example. But social interactions do the same thing to the reward system as yummy treats. When we engage in pro-social behavior, the reward system is activated in the same way as if we were receiving a physical reward. Pro-social behavior includes things like helping others, spending time with loved ones or giving and receiving praise. The difference between social rewards and physical rewards is our awareness of them. Most of us know that when we eat our favorite food, we will enjoy it and get a hit of dopamine. But we don’t always think about the fact that our social experiences can – and do – come with those same rewards.

This means that a hug from a friend can trigger a series of connections in the brain – dopamine traveling along two pathways that send positive feelings, help you notice and appreciate the experience, and create a memory that will help you repeat it in the future.

Mirroring and Mirror Neurons

Mirroring is a process of the brain that mirrors, or mimics others. We use mirroring on a daily basis to learn from and imitate those around us. Mirroring can include everything from facial expressions, gestures, speech patterns or even emotions. Mirroring can be found in small moments, like leaning forward when the person across from you leans forward, or the contagious effect of yawning. Scientists have identified that the sound of a person laughing causes the brain to prepare to laugh. (Ever got the giggles with a group of friends? You’ve seen first-hand the effect of mirroring.)

Most of the time these imitations are subconscious and generally go unnoticed. But sometimes as a bystander, you can observe moments of mirroring, like a parent and child sitting in the exact same way on the couch next to each other, or a couple walking in step down the street. We use mirroring not just for fun, but because it helps keep us safe and as part of the in-group in social settings.

Mirroring is rooted in specialized brain cells called “mirror neurons”. These are the brain cells at work when we perform actions and when we see others perform actions. Because they were only discovered within the last 30 years, we are still learning their full capabilities. But we do understand that mirroring is a component of the social brain that helps us connect with others.

There’s much more to the very complex organ that is the brain. Neurons firing and wiring connect us to others and drive us to be social. But this is enough of a science lesson for one day!

Loneliness and Social Pain

Now, remember those statistics on loneliness at the beginning of this post? Here’s where that information becomes critical.

Let’s put the brain on hold for a moment and think about the body. Everyone knows that bodies are designed for certain functions, like movement or eating and digesting food and water. And we all know that our bodies can be in pain when we aren’t able to perform the tasks that the body is designed to do. Injuries, illnesses and other challenges can interfere with the body’s ability to move, eat and digest, and more. And when this happens, we experience physical pain.

Back to the brain. Guess what? The same thing is true. The human brain is designed to be social. When we’re unable to engage in social interactions, the brain experiences pain.

Through neural imaging, researchers have discovered that the brain processes social pain in much the same way as it processes physical pain. Physical and social pain rely on the same neural circuitry. At first, it may seem unlikely that the brain processes physical and social pain similarly because we don’t consciously process them in the same way. Stub your toe? You feel that throbbing. But moved to a new city and haven’t made any real friends yet? That doesn’t seem like it's the same as a hurt toe. If you think about it, we intuitively do process social pain as pain. Think about the phrases we use when we talk about social pain: “He broke my heart.” “They hurt my feelings.” “It was a gut punch.”

Social pain also leads to physical pain. Think back to this statistic from the Surgeon General’s report:

The mortality impact of being socially disconnected is similar to that caused by smoking up to 15 cigarettes a day.

The research behind this was based on statistical models for mortality. People with fewer social connections are more likely to die prematurely than those with strong social networks. They then compared this data to established data on other risk factors such as cigarette smoking, alcohol consumption, obesity and more. They determined that this early mortality for loneliness aligned with the mortality rate for people who smoke up to 15 cigarettes a day. Early mortality is certainly an indication of pain.  

Loneliness can serve as the indicator for need of human connection. Just like thirst can tell us that we need to drink water, a feeling of loneliness is our brain and body’s way of telling us to seek out social connection.

The science is clear. We need human connection. So, attend that meetup event. Call up an old friend for a chat. Go through the checkout line instead of self-checkout. Learn your mail carrier’s name. Each of these small interactions helps us create a sense of community.

Take it from the Surgeon General and the countless research studies that have informed this base of knowledge. We are wired to connect, and our survival and livelihood depends on it. Doctor’s orders.

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