The Dunbar Limit: Why your brain can’t handle 1,000s of friends

Your brain wasn’t built for a thousand friends

When social media first took off, platforms ran into a problem: your brain. 

Specifically, something called the “Dunbar limit.”

British anthropologist Robin Dunbar proposed in the 1990s that humans are cognitively capped at maintaining about 150 stable social relationships. 

He calculated this number by studying the size of the neocortex — the part of the brain responsible for managing social relationships — and its correlation to group sizes in primates and humans.  He found that the average human brain size allows for humans to comfortably maintain 150 stable relationships

Looking back at history, you see this magic number everywhere. Hunter-gatherer clans. Military units from the Roman empire to modern-day army companies. Factories and workplaces. They all naturally cluster into groups of around 150.

The Dunbar limit isn’t just one number, though. Our relationships form layers: five loved ones, 15 close friends, 50 friends, and 150 stable relationships. Beyond that, we can manage acquaintances (500 people) or familiar faces (1,500). But 150 is critical — it’s the tipping point where relationships become too hard to maintain.

For social media companies, this hardwired limit posed a problem.

Social Media’s Workaround

Social media platforms didn’t just ignore the Dunbar limit — they bulldozed it. Platforms like Facebook and Instagram made it easier than ever to connect with thousands of people. With a single click, you could "friend" an acquaintance, follow a stranger, or join a massive group. Suddenly, 150 felt small, even irrelevant.

But while the size of our networks has changed, our brains haven’t. Social media has lowered the cost of forming connections, making it easier to expand our outer circles — those weak ties and acquaintances in the 500–1,500 range. 

But at the same time, it’s disrupted how we allocate our limited “social capital” — the time, energy, and effort we use to maintain relationships.

Traditionally, we spend 60% of our social time on close connections (like loved ones and close friends) and 40% on the outer circle. Social media disrupted that balance. Now, hours are spent on one-sided relationships: consuming content from celebrities, influencers, or acquaintances we barely know, and comparing ourselves to them.

Social media may make connections cheaper to form, but it hasn’t reduced their cost to maintain. Instead, it spreads our finite resources too thin. So while social media companies think they’ve shattered the Dunbar limit, what they’ve really succeeded at is getting us to invest more in weak ties and less in the relationships that truly matter.

Angry, defensive primates

The consequences of exceeding the Dunbar limit go beyond strained time and energy. 

Max Fisher, author of The Chaos Machine, argues that social media giants have bypassed “millions of years of evolution” to push us beyond our cognitive and emotional limits.

Fisher points to studies on rhesus monkeys, which have similar Dunbar limits to humans. When forced into larger groups, the monkeys exhibited more aggression, distrust, and hierarchy enforcement. Humans aren’t much different. Online, we see tribal behaviors emerge: people defending ideologies, attacking dissenters, and enforcing social hierarchies on platforms like Facebook and Twitter, as if their survival depends on it.

The result? A society more connected than ever but also more socially fatigued, distrustful, and defensive. Shallow virtual interactions replace meaningful shared experiences, leaving us emotionally drained and perpetually dissatisfied.

Dunbar’s Greatest Fear

In bypassing the Dunbar limit, we’ve gained quantity but lost quality. Comparing ourselves to millions of others, arguing with strangers, or endlessly scrolling through weak ties — none of it feels natural because it isn’t.

When asked what he fears most about the rise of virtual interaction, Robin Dunbar doesn’t hesitate. “In the sandpit of life, when somebody kicks sand in your face, you can’t get out of the sandpit. You have to deal with it, learn, compromise,” he says.

Dunbar fears that as face-to-face interactions are replaced by online connections, we’ll lose the skills that make us truly social. Online, it’s easy to avoid conflict—blocking, muting, or walking away—rather than resolving it. This erodes the very group experiences that teach us how to build trust and navigate relationships.

And instead of expanding our social circles, social media may actually be shrinking them. By overwhelming us with weak ties and shallow interactions, we risk losing the ability to form and sustain even the 150 meaningful relationships our brains are built for.

In trying to connect with everyone, we might end up truly connecting with no one.

COMMUNITY CORNER

TIPS & TRICKS

Reclaim your social capital

The Dunbar limit reminds us that our brains are wired for meaningful, face-to-face connections — not endless scrolling or superficial ties. Social media might pull us in every direction, but here’s how to push back and prioritize what matters.

1. Reclaim the 60/40 Split
   Dedicate 60% of your social time this week to close connections. The next time you catch yourself spending your time and effort on knowing the lives of a social media stranger, redirect that energy to your core people. Call your best friend, schedule a dinner with family, or spend time with your inner circle—offline.
   

2. Invest in Shared Experiences
   Shared experiences are the glue of real relationships. Plan activities with your core group—whether it’s a game night, hiking, or cooking together. Laughing over a meme is nice, but it’s nothing compared to laughing together in person.
   

3. Reevaluate Weak Ties

   Take a step back and notice how much energy you’re giving to parasocial or one-sided relationships—following influencers, tracking celebrities, or scrolling acquaintances’ updates. These connections might feel engaging, but they rarely give back. Shift your focus toward the people in your life who reciprocate your care and attention.
   

4. Redraw Your Social Boundaries
   Treat your attention like a resource. Ask yourself: Does this person, group, or activity belong in my 150? Start saying no to shallow interactions that drain your energy.

RESOURCE & RECOMMENDATIONS

• Ever feel like you “know” that influencer or celebrity? This deep dive explores the history of parasocial relationships, their rise with social media, and what they’re doing to our brains.

• With Thanksgiving around the corner, here’s a look back at my experiment with a no-phone Thanksgiving. Plus, some tips to try your own. 

• Want to understand the evolutionary psychology behind friendship and the Dunbar limit? Watch this interview with Robin Dunbar himself for insights on why your brain is wired for smaller circles.

• I’ve never seen anything like the Light Phone — it’s sleek, minimalist, and designed to help you disconnect. It looks amazing, but fair warning: it’s not cheap. Check it out if you’re ready to splurge on simplicity.

• Catherine Price is a science journalist who digs deep into the impacts of tech on our lives. Her book How to Break Up with Your Phone, she offers a straightforward, 30-day plan to help you reclaim your time from your device—without going cold turkey.