Do Intelligent People Prefer Fewer Friends? What the Study Found

Originally published 2017-04-13.

Do intelligent people prefer to be alone? The idea comes mostly from one 2016 study by evolutionary psychologists Norman Li and Satoshi Kanazawa. It found that, among young American adults, seeing friends more often went with slightly higher life satisfaction for most people, but for those with the highest test scores the link ran the other way. It did not show that clever people are loners, that loners are clever, or that friendship makes anyone unhappy.

That is a narrower finding than the headlines it produced, such as "smart people are happier with fewer friends." Below is what the study measured, how the authors explained it, where it is weak, and what the wider research says about solitude and connection.

What the 2016 study measured

Li, then at Singapore Management University, and Kanazawa, at the London School of Economics, published their paper in the British Journal of Psychology under the title "Country roads, take me home… to my friends." They used data from the National Longitudinal Study of Adolescent Health (Add Health), a large US survey. Their sample was about 15,000 people aged 18 to 28, interviewed in 2001 and 2002.

Each measure was simple:

• Life satisfaction came from one question: how satisfied are you with your life as a whole, on a five-point scale.
• Socialising was the number of times in the past seven days the person had hung out with friends or talked to them on the phone for more than five minutes.
• Population density was the number of people per square kilometre where they lived.
• Intelligence was estimated from a short vocabulary test, the Peabody Picture Vocabulary Test, scaled like an IQ score.

What it found

Two patterns held across the sample. People living in more crowded places reported slightly lower life satisfaction, and people who socialised with friends more often reported slightly higher life satisfaction, once marital status was taken into account. (Married people tended to be happier but saw friends less, which hid the friendship link until the authors controlled for it.)

Then came the result that went viral. Intelligence changed both patterns. The downside of crowded places was weaker for higher scorers. And the upside of seeing friends shrank as scores rose, until, for people roughly one standard deviation above average, more frequent socialising went with slightly lower satisfaction.

The key word is slightly. The authors report the effects in terms of Cohen's d, a standard way to express size. For socialising, the values were about 0.05 for lower scorers and minus 0.03 for higher scorers. By common convention, anything below 0.2 is a small effect. These are real statistical patterns in a big data set, but they explain a tiny share of why one person is happier than another.

The savanna theory behind the claim

To explain the results, Li and Kanazawa proposed what they call the savanna theory of happiness. The idea is that the human brain evolved for life in small bands of around 150 people, with frequent contact with family and allies and few strangers. Modern conditions such as crowded cities or rare contact with friends might still affect our wellbeing as if they carried their ancestral costs.

The authors also argue that general intelligence may have evolved to deal with new, unusual problems. If so, more intelligent people might be less tied to those ancient preferences, which would explain why density and friendship mattered less to them.

Economist Carol Graham of the Brookings Institution, who studies happiness, offered a simpler reading in a 2016 Washington Post interview. She suggested that people with high ability may spend less time socialising because they are focused on long-term goals such as study or work, so frequent socialising can feel like a distraction. Both explanations are possible; the data cannot decide between them.

Limits worth knowing

The authors list several limitations themselves, and they matter for anyone tempted to apply the result to their own life:

• It is correlational. The study cannot show that socialising lowers anyone's happiness. Unhappy people might seek out friends more, or something else might drive both.
• The measures are thin. One question about life satisfaction and one week's count of social contact are rough snapshots. "Friends" was not defined, and online contact was not clearly captured.
• Intelligence was a vocabulary score. It is a reasonable proxy, but it measures verbal ability, not every kind of intelligence.
• The sample was young. Everyone was between 18 and 28, at a stage of life when social habits change quickly.
• The effects are small. Even if the pattern is real, it tells us very little about any single person.

Popular write-ups often added claims the paper never made, for example that highly intelligent people are "evolving past" the need for others. Nothing in the data supports that. The study did not find that intelligent people have fewer friends, only that, for them, seeing friends more often in a given week was not linked to extra satisfaction.

Solitude is not loneliness

One useful thing the study points to is that time alone and loneliness are different. Solitude is chosen time on your own. Loneliness is the painful feeling that your connections are fewer or weaker than you need. You can feel lonely in a crowd, and feel content alone in a room.

Research on solitude suggests it can calm strong emotions and help people rest and think, especially when it is chosen rather than imposed. Loneliness, by contrast, has been linked to poorer physical and mental health, which is why the US Surgeon General issued an advisory on social isolation in 2023. Wanting quiet evenings is not a warning sign. Feeling cut off and unhappy about it is worth taking seriously, and if it persists, talking to a doctor or counsellor can help.

Finding the balance that suits you

Preferring a book to a party does not prove genius, and loving a busy social life does not mean anything about your intelligence. A more useful question is which kinds of contact feel good and sustainable for you right now. A few practical ideas:

• Favour depth over volume. Many people get more from one long conversation with a close friend than from a crowded night out.
• Plan contact around shared interests. Clubs, classes or volunteering give conversation a focus, which suits people who find small talk tiring.
• Protect your quiet time without guilt. Time alone to recharge is normal, and saying no to some invitations is fine.
• Notice how you feel afterwards. If you come away from people drained, adjust the format; if you feel low after long stretches alone, reach out more.

The Li and Kanazawa study is an interesting data point about averages in a large group. It is not a personality test, and it is no reason to give up on friendship or to feel odd about enjoying your own company.

Sources: Li, N. P. and Kanazawa, S. (2016), Country roads, take me home… to my friends: How intelligence, population density, and friendship affect modern happiness, British Journal of Psychology (PDF); earlier summary by I Heart Intelligence.