Scientists have discovered a hidden mechanism behind the choice of friends

However, a new study suggests that our brains may make such decisions in a much more ancient and ‘practical’ way. According to the researchers, when choosing friends, we unconsciously look for qualities that helped people survive thousands of years ago.

The study has been published in the journal *Evolution and Human Behaviour*.

Friendship turns out to be older than modern goals

Traditionally, psychologists have believed that people choose friends based on their current needs. For example, to study together, build a career or tackle everyday tasks.

However, researchers from the University of California have suggested that this choice may be determined not only by present-day circumstances, but also by evolutionary mechanisms that took shape as far back as the hunter-gatherer era.

If this hypothesis is correct, people must unconsciously look for qualities in potential friends that once made a person a valuable ally.

What proved to be most important

To test this idea, the researchers conducted two experiments.

In the first, 156 students, after spending half an hour getting to know one another, assessed how much they would like to be friends with one another.

In the second, 444 volunteers rated photographs of strangers, and the researchers then compared these ratings with the qualities the participants considered important for achieving their current life goals.

The results showed that the attractiveness of a potential friend was more often determined by factors other than current goals.

The most important factors turned out to be:

• willingness to cooperate;
• reliability;
• confidence and the ability to take the lead;
• high social status;
• physical attractiveness.

It was precisely these qualities that best predicted a desire to form a friendship.

Why does the brain make such a choice?

The authors believe that such preferences may have developed as far back as prehistoric times.

For ancient people, a good friend was not merely a pleasant companion. Joint hunting, protection from enemies, the procurement of food and the upbringing of children all depended on them.

Consequently, the human brain may have developed a kind of ‘social filter’ that still helps us to quickly assess potential allies.

Researchers figuratively refer to these as ‘social taste receptors’ — innate preferences that operate automatically.

This does not mean that interests are unimportant

The authors emphasise that the study does not prove that friendship is determined solely by evolution.

Modern life goals, shared interests, values and experiences also play a major role.

However, the results show that a significant proportion of our affinities may arise unconsciously — even before we have time to consider how a person might be useful to us or how similar they are to us.

Why this is important

This research helps us better understand how social bonds are formed and why first impressions of people are often so strong.

It also shows that the mechanisms that helped people survive thousands of years ago may continue to influence our decisions even in modern society.

Background

Evolutionary psychology suggests that many aspects of human behaviour were shaped by the lifestyle of ancient hunter-gatherers. This is not a matter of conscious choice, but of psychological mechanisms that may have become entrenched through natural selection.

In a new study, researchers have obtained data consistent with this hypothesis, though they note that the choice of friends is likely determined by a combination of ancient evolutionary preferences and modern-day circumstances.

Source

Adar B. Eisenbruch et al. What do people want in a friend? Cues of ancestral cooperative partner value predict same-sex friend preferences. Evolution and Human Behaviour (2026).