Why Social Connection Is Exercise for Your Brain

Stacy Lu

Updated June 23, 2026

The book cover of "Why Brains Need Friends: The Neuroscience of Social Connection" and its author, Dr. Ben Rein, sitting next to it

Neuroscientist Ben Rein explores the science of social interaction in "Why Brains Need Friends."

AARP (From left: Random House; Courtesy Elena Zhukova)

Humans are social animals. Ben Rein, a neuroscientist at the University of Buffalo and author of the book, “Why Brains Need Friends: The Neuroscience of Social Connection,” studies how our brains are wired for socializing. Here, he tells Staying Sharp why being social supports brain health and how to forge modern connections in natural, low-stress ways.

Why are our brains wired to crave social contact?

Historically, humans have existed in groups, and that has been extremely beneficial for our survival since our days as hunter-gatherers. We have many sophisticated systems for understanding each other. We’re very good at reading the emotions of others; even when no words are spoken, you can pretty much tell what someone’s feeling. That makes us very capable hunters, defenders and collaborators. By sticking together, we became more likely to survive. So our brains are wired to reward us for being around others and to punish us if we are not.

You have said that isolation causes a stress response in the brain. Is it the same response that we have when we face a threat?

Our body’s stress responses are the same no matter what’s stressing us. Obviously, your response and the way you feel would be different if someone is pointing a gun at you versus you are experiencing isolation. But the body triggers the same biological systems to let us know that something is wrong and you need to escape this threat. If someone points a gun at you, it’s fight or flight, run or attack. If it’s isolation, it is more of a search for companionship — looking for an escape from the circumstances you’re in.

You have written that social activity is like exercise for the brain. Can you explain?

The brain is like a muscle in that when you use it, it gets stronger, and when you don’t, it gets weaker. Socializing is a very robust exercise for the brain because there’s so much information to take in. Facial expressions, vocal tone, body language and eye contact engage many brain systems.

As time passes, the brain’s natural inclination is to get weaker and to shrink. We can become less sharp. But when you consistently use your brain, the connections between brain cells and regions get strengthened or at least sustained. So when you’re activating all these brain areas, you’re holding that off, or keeping the muscle strong, so to speak. There’s evidence that older people who live more social lives have much larger brain volume. They’re exercising the brain by using it more.

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What counts as meaningful social connection?

I like to think about social connection as a swimming pool. You can swim into the deep end by having a heart-to-heart with your best friend, but you can also dip your toes into the shallow end by waving to your neighbor walking by. I think about this pool of connection as the fountain of youth. The deeper you go, the stronger a dose you’ll get, but you don’t always have to go into the deep end.

Some people like to spend a lot of time alone. What’s the difference between isolation and loneliness?

Loneliness is a psychological state. You can be lonely while you’re around other people. For example, you go to a party by yourself. You’re standing in a corner looking around seeking contact, and you feel lonely. Isolation, meanwhile, is an objective state of solitude. You can be isolated without being unhappy. For example, you can come home from a week-long vacation with friends and be at home for days by yourself without feeling lonely.

The issue is that people who don’t crave interaction are much more prone to being isolated for long periods. Extroverts need to socialize all the time to be happy. Introverts can go a long time and not feel lonely – but they still need connection for optimal physical and mental well-being.

Does age change our need for social connection?

There’s no reason to think the brain’s need for connection changes throughout life. In America, the amount of time that people spend by themselves rises consistently as they age. People 65 and up spend more time by themselves than they ever have. This is something I worry about, because isolation is linked to a range of health issues. It does seem that people become more content with solitude as they age, but that may be a by-product of being forced to spend more time alone.

Can some social situations be stressful for certain people?

Yes. I have a social journaling exercise on my website, because everyone’s preferences are different. When you come home from an interaction, that’s when you do the exercise, which asks How you felt going into the activity, and how did you feel coming out of it? Did you feel comfortable? Did you enjoy the company? What was your favorite part/your least favorite part about it? It becomes obvious which activities are good for you and which are not.

There are differences in crowd sizes, for one. Say you’re across the table from someone, looking into their eyes and having a direct conversation. Is that comfortable? Do you like that kind of focused interaction, or is it too intimate? On the other hand, is a group of 14 people at a dinner party going to be overwhelming or is that your jam? Your best time of day for socializing is another factor. For example, I have a very regimented sleep schedule and need to be in bed by 10. You learn where to set limits.

_{This interview has been edited for length and clarity.}