Personality and friendship: how your traits shape the friends you make and keep
By the 64 Types team · Updated October 13, 2026 · 5 min read · 8 peer-reviewed sources
Personality shapes friendship mainly through two traits: extraversion helps people make friends, and agreeableness helps people be chosen as friends and keep friendships going. In a study of new university students, extraverts nominated more friends while agreeable students were nominated more often by others, and people tended to pick friends similar to themselves in agreeableness, extraversion and openness.[1] A review of the research concluded that agreeableness has the most consistent effects on friendships, followed by neuroticism, while the effects of extraversion, conscientiousness and openness are less consistent.[2]
This guide covers how friendships form, what each trait contributes, and practical ways to use your own profile.
How friendships form among strangers
Studying friendship formation requires catching people before they have friends, which is why researchers like university freshers. In one such study, 205 students (average age 19) reported who their friends were at five points during their first year. Friendship networks became much more cohesive in the first three months and then stabilised.[1]
Personality mattered in three ways:[1]
- Extraverts chose more friends. They nominated more classmates as friends than introverted students did.
- Agreeable students were chosen more. Others were more likely to name them as friends.
- Similarity mattered. Students tended to choose friends with similar levels of agreeableness, extraversion and openness.
Note the asymmetry: extraversion relates to how actively you reach out, and agreeableness to how attractive you are as a friend.
Personality shapes friendships more than the reverse
Does having lots of friends make you more outgoing, or do outgoing people collect friends? A study that followed 132 students for 18 months after starting university found that personality predicted later relationship features, such as the number of peer relationships, conflict with peers and falling in love, but relationship features did not predict later personality. Extraversion, agreeableness and conscientiousness were the traits involved.[3]
Over that period, at least, the arrow mostly pointed from personality to relationships.
What each trait contributes
Agreeableness: the most consistent
A review of personality and friendship development found that agreeableness had the most consistent effects on both friendships and romantic relationships.[2] Agreeableness is also the Big Five trait most closely tied to how people handle interpersonal conflict.[4] In 64 Types it is the F/T letter.
Emotional stability: second
Neuroticism was the next most consistent trait in the same review.[2] It is not part of the classic four-letter type; in 64 Types it is the C/R letter. See emotional stability.
Extraversion: more friends, faster
Extraversion predicted the number of peer relationships[3] and how many friends new students chose.[1] Its effects across studies are less consistent than those of agreeableness,[2] which fits the idea that it affects how many friends people make more than how good those friendships are.
Openness and conscientiousness
Openness mainly showed up through similarity: students chose friends with similar openness.[1] Conscientiousness predicted some relationship features in the longitudinal study,[3] but overall the effects of both traits on friendship are inconsistent.[2]
Honesty-Humility: fairness and trust
Research on friendship and Honesty-Humility specifically is limited. But a meta-analysis of economic-game experiments found that traits relating to exploiting others, including Honesty-Humility, were consistent predictors of prosocial behaviour,[5] which is relevant to whether a friend plays fair when it costs them something. See the Honesty-Humility guide.
Similarity: why friends resemble each other more than couples do
Among new university students, similarity in agreeableness, extraversion and openness helped explain who became friends.[1] That contrasts with research on married couples, where similarity in personality explained less than 0.5% of the variance in satisfaction once each partner’s own traits were accounted for.[6]
The two findings answer different questions, one about who chooses whom and the other about who is satisfied, so they do not contradict each other. Together they suggest that similarity may help people find each other but matters much less for how good the relationship turns out to be. The review of friendship research made a similar point: the effects of a person’s own agreeableness and neuroticism are more consistent than the effects of matching.[2]
If you mainly befriend people like you, deliberately keep a few friends who differ on openness or extraversion. They are likely to introduce you to activities and people you would not find on your own.
Your friends know things about you that you do not
Friends are not only shaped by your personality; they are also good judges of it. In a study comparing self-ratings with ratings by friends and strangers, friends were the best judges of intellect-related traits, while the self was best for neuroticism-related traits.[7] Across many studies, raters who are closer to a person are more accurate, especially for less visible traits such as emotional stability.[8]
Share your 64 Types result with a close friend and ask where they disagree. Differences on visible traits like extraversion, or on evaluative ones, are worth discussing. Our compare tool lets them take the test and see both profiles side by side.
Introverts and friendship
Introverts tend to nominate fewer friends in new settings,[1] but the number of friends is not the same as the quality of friendships, and the research reviewed here measured mainly network size and formation. If you are introverted, the traits that matter most for keeping friendships, agreeableness and emotional stability,[2] are independent of introversion.
New friendships form fastest in the first months of a new setting.[1] If you are introverted and starting a new job, course or city, invest a little extra social effort early, when networks are still forming, then settle into your preferred pace.
Practical friendship tips by letter
These are practical suggestions based on what each trait tends to involve, not tested interventions.
| If you are… | Strength in friendship | Try this |
|---|---|---|
| E (Extraverted) | You start friendships easily | Follow up one-to-one; breadth is easy for you, depth takes deliberate time |
| I (Introverted) | You often prefer deeper one-to-one time | Initiate occasionally; friends may read reserve as disinterest |
| F (Compassionate) | People are drawn to your warmth | Say no when you need to; friendship survives honest limits |
| T (Tough-minded) | You give candid advice | Ask “do you want advice or support?” before giving feedback |
| J (Organized) | You make plans happen | Leave space for spontaneous invitations from others |
| P (Flexible) | You are fun and adaptable | Put recurring catch-ups in the calendar so friendships do not drift |
| C (Composed) | You steady friends in a crisis | Share your own struggles too; support should flow both ways |
| R (Responsive) | You notice when friends are struggling | Choose confidants who calm you rather than amplify worry |
| M (Modest) | You are trusted and fair | Let friends help you; modesty can make you hard to support |
| A (Ambitious) | You bring drive and connections | Keep some friendships entirely free of networking |
See how these combine for your full code on the type pages, for example ESFJ or INTP.
Frequently asked questions
Which personality trait matters most for friendship?
Agreeableness has the most consistent effects, followed by neuroticism (lower is better for relationships).[2]
Do extroverts have more friends?
They tend to make more friends in new settings and have more peer relationships.[1][3] That is about quantity; effects on friendship quality are less consistent.[2]
Do we choose friends who are like us?
Partly. New university students tended to choose friends with similar agreeableness, extraversion and openness.[1]
Do friends change your personality?
In an 18-month study of students, personality predicted relationship features but relationship features did not predict later personality.[3]
References
- Selfhout, M., Burk, W., Branje, S., Denissen, J., van Aken, M., & Meeus, W. (2010). Emerging late adolescent friendship networks and Big Five personality traits: A social network approach. Journal of Personality, 78(2), 509–538.
- Harris, K., & Vazire, S. (2016). On friendship development and the Big Five personality traits. Social and Personality Psychology Compass, 10(11), 647–667.
- Asendorpf, J. B., & Wilpers, S. (1998). Personality effects on social relationships. Journal of Personality and Social Psychology, 74(6), 1531–1544.
- Jensen-Campbell, L. A., & Graziano, W. G. (2001). Agreeableness as a moderator of interpersonal conflict. Journal of Personality, 69(2), 323–362.
- Thielmann, I., Spadaro, G., & Balliet, D. (2020). Personality and prosocial behavior: A theoretical framework and meta-analysis. Psychological Bulletin, 146(1), 30–90.
- Dyrenforth, P. S., Kashy, D. A., Donnellan, M. B., & Lucas, R. E. (2010). Predicting relationship and life satisfaction from personality in nationally representative samples from three countries: The relative importance of actor, partner, and similarity effects. Journal of Personality and Social Psychology, 99(4), 690–702.
- Vazire, S. (2010). Who knows what about a person? The self–other knowledge asymmetry (SOKA) model. Journal of Personality and Social Psychology, 98(2), 281–300.
- Connelly, B. S., & Ones, D. S. (2010). An other perspective on personality: Meta-analytic integration of observers’ accuracy and predictive validity. Psychological Bulletin, 136(6), 1092–1122.
How we write guides: every research claim cites a peer-reviewed source, effect sizes are reported as published, and advice that goes beyond the evidence is labelled as a practical tip. See our methodology. Found an error? Email support@64types.app.
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