Friendship Group

The Basic Idea

When people hear of an “intimate relationship,” they likely think of a romantic one. However, friendships are another form of intimate relationships that have profound influence on our identities, well-being, and decisions.1 Friendships are built on the same building blocks as romances: respect, trust, reciprocity, and social support. Their presence, especially when we’re younger, can shape our life experiences.

But how exactly do friendships form? How do we choose the people with whom we’ll spend so much of our lives, and what predicts whether our friendships will last or not? Do all friendships form similarly? What happens if we don’t have stable friendships? Given their profound influence, there is no shortage of research on these relationships.

Find a group of people who challenge and inspire you; spend a lot of time with them, and it will change your life.

– Amy Poehler, writer and producer, in her graduation speech to Harvard University’s class of 2011

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Social baseline theory holds that our responses are dependent on our relationships with those around us.2 After all, humans evolved to be around others; social relationships were efficient in hunter-gatherer communities in which collaboration for resources was a necessity for survival.

Clearly, friendship groups have been important throughout history. Being social is our baseline, so we’ve come to expect the presence of others: we know this presence generally means that situations will be less taxing and energy depleting.2 Researchers have found that hills are perceived as steeper and further away when people are tired, stressed, or in a bad mood. However, the presence of a friend makes the hills seem closer and less steep, reducing perceived risk.

One reason that research on friendship has amassed popularity over the years is that, compared to most other relationships, friendships are uniquely voluntary.3 Friendship is relatively non-institutionalized: it lacks the strict norms and rituals that characterize romantic and familial relationships. There are two main perspectives in the field of research on friendship formation and maintenance:

  1. Dispositionalists: those who view friendship as completely voluntary and pay attention to internal factors that bring people together (i.e. personality traits, temperament).
  2. Structuralists: those who emphasize the effects of social structure and influences beyond individual control (i.e. power and status hierarchies).

Dispositional researchers focus on the interactive processes in friendships, while structuralists tend to study entire friendship networks.

Much research has examined how friendship groups form and strengthen.4 Specifically, researchers have found that geographic proximity, family background, and common interests increase the likelihood that two people will interact. This research is supported by the fact that people are not very likely to approach strangers on the street in attempts to make friends. Rather, friendships tend to form in constructed environments, such as workspaces or school clubs. Since people self-select themselves to be in those environments, the likelihood of characteristics (such as geographic proximity and common interests) influencing friendships is increased.

Researchers have been developing agreement models of social interaction since the 1940s, focusing on how the degree of agreement between members of a group will influence the strength of their relationships.5 When people first start interacting, there is not much structure. They share information on some values and attitudes, and may get a sense of whether there is agreement between parties. As interactions and agreement on these values build, friendships become stronger.

However, early acquaintances in groups are held together by relatively weak friendship ties and may reflect such weaknesses during times of disagreement. If people can move past minor disagreements, the friendship ties will strengthen and foster a stable friendship group. Unfortunately, this stability can be disrupted upon presentation of new and important issues. While friendships are initially built on agreement of existing values, a new issue that causes strong disagreement can result in conflict and disrupt the group. In times of conflict, friendship groups may experience further division between members who were not involved in the original conflict, due to unwritten alliances within the group.


Most of the foundational research on friendship groups has focused on middle-class, Caucasian post-secondary students.3 While both female and male participants are included in research, many categories of friendships are underrepresented, such as non-heterosexual friendships, non-white friendships, eldery friendships, and differences between female and male friendships. As a result, contemporary research has shifted to exploring unique intersections and how they influence friendships.

Gender and Race

Since people belonging to gender or sexual minorities may face increased familial rejection and estrangement, they often surround themselves with “chosen families”: friends who fulfill emotional needs and provide support.6 Within same sex-friendships, research has found that women’s friendships are usually characterized by emotional sharing and self-disclosure, while men’s friendships revolve around shared activities and friendly competition.1 Having cross-racial friends has been found to enhance individual and collective cultural competence.7

Research on elderly women discovered that those who lived alone participated in senior center activities more frequently.8 They created social networks outside of their center environment, emphasizing the importance of a strong social support network for the emotional well-being of older women living alone relative to older married women. 

Personality and Identity

Contemporary research has also focused on friendship groups in the context of personality and identity. The dark triad refers to three personality traits:

  1. Narcissism: an excessive self-admiration and self-involvement that results in ignoring the needs of others;
  2. Machiavellianism: thinking of oneself as smart enough to exploit others; and
  3. Psychopathy: excessive thrill-seeking and antisocial behavior.1 

These traits are referred to as “the dark triad” because they all result in disadvantageous behaviors toward others, such as arrogance, manipulation, hostility, and low levels of agreeableness. These personality traits tend to have corrosive effects on friendships.

Contrary to the characteristics of the dark triad, our relational self-construal is the extent to which we think of ourselves as interdependent. The higher our relational self-construal, the more motivated we are to support others and be a dependable friend.


Plenty of research has examined friendship development across the life cycle.1 Preschool children have rudimentary friendships, but success in childhood friendships paves the way for better adult outcomes. As children’s cognitive development deepens, allowing them to become increasingly appreciative of others’ perspectives and needs, their interpersonal needs shift from acceptance in the early elementary years, to intimacy in preadolescence, to sexuality in the teen years. Adolescents spend less time with their families and more time with their friends, so they increasingly turn to friends for satisfaction of their attachment needs.

As young adults head to university and often move away, satisfaction with their social networks tends to drop, but rises again by the end of the year. After university, young adults tend to interact with fewer friends but their remaining friendships grow deeper. Couples in their midlife phase tend to see friends less, but their overall social networks increase due to the addition of their partners’ families. Socioemotional selectivity theory posits that elderly people have smaller social networks since their interpersonal goals shift from pursuing future-oriented goals to emotional fulfillment. While younger people seek out many social interactions to ensure increased access to opportunities (i.e. employment and meeting significant others), elderly people prioritize quality over quantity.


A popular area of current friendship research is its relationship to happiness. Among university undergraduates, those with strong romantic relationships and close friendships are happier than those without such attachments.9 Having happy friends is also beneficial: each happy friend increases our chances of happiness by 15%, and each happy friend-of-a-friend increases our chances of happiness by 10%, even if we’ve never met that person.1 

On the other hand, each unhappy friend we have decreases our likelihood of happiness by 7%.1

Returning to the relationship between romance and happiness, friend groups can either make or break our romantic relationships through approval or disapproval. In fact, the more our friends like our romantic partners, the more committed we will be to them.


While a strong friendship group is important for our well-being, friendships - especially during adolescence -  also come with dark sides.9 Friends tend to co-ruminate: extensively discussing and speculating about their problems, thereby dwelling on negative feelings. While co-rumination can increase closeness, it is also associated with empathic distress and internalization.

Peer pressure is also common in adolescence, specifically in regard to sexual activity and substance use.10 One study from 2005 found that just the presence of friends can change risk-taking behavior: risky driving decisions decreased with age but all age groups were riskier when their friends were watching them, and these peer influences were more pronounced among adolescents than adults.11 Many studies have assessed risky driving in adolescence and have been influential for designing driving laws for new, often teenage drivers.

Researchers have also paid attention to friendships groups in the field of suicide and nonsuicidal self-injury. Nonsuicidal self-injury may result in poor emotional regulation as a result of decreased interpersonal support, especially for young people.12 As a result, youth who self-injure are more likely to have close friends who also self-injure, and can therefore experience contagion: exposure to suicide-related behaviors that transmits an increased risk for oneself. 13 A 2018 model of nonsuicidal self-injury reported that if individuals admire someone who engages in self-injury, they may emulate the behavior to maintain a positive self-image.14

Case Study

Friendship group influence on self-injury

Nonsuicidal self-injury is the deliberate destruction of body tissue without intent to die, and has become a major public health concern among adolescents.15 Adolescents’ engagement in self-injury may be predicted by the extent to which they perceive their friends to engage in similar behaviors. While much research has assessed peer influence on nonsuicidal self-injury, no distinction has been found between casual peers, friendship groups, and best friends.

A group of Chinese researchers set out to study the difference of peer influence between best friends and larger friend groups as predictors of nonsuicidal self-injury through socialization and selection effects. The researchers assessed over 6,000 high school students by administering questionnaires related to nonsuicidal self-injury, maladaptive impulsive behaviors (i.e. binge eating, spending sprees, verbal outbursts, physical fights), and depressive symptoms.15 Participants were asked to name and rate five of their closest friends to determine friend groups, with the highest ranked friend known as the “best friend”.

After controlling for depressive symptoms and maladaptive impulsive behaviors, the researchers found that best friends’ nonsuicidal self-injury status significantly predicted adolescents’ own engagement in self-injury over a six-month period.15 As for general friend groups, statuses of nonsuicidal self-injury longitudinally predicted adolescents’ own frequency. The researchers also found that adolescents who self-injured tended to select friend groups with other members who also did so.

The effects of friend group influence on adolescents’ nonsuicidal self-injury could either be a result of contagion, such that adolescents self-injure as a result of their friends’ influences, or a result of selection effects, such that adolescents who self-injure foster close connections with similar peers.15 Overall, the study shows how peer socialization and selection play a role in nonsuicidal self-injury, highlighting a potentially harmful aspect of friendship groups.

Friendship group identification and self-concept

Much research has shown that adolescents’ positions in peer networks are related to indicators of social competence, such as loneliness, aggression, and general self-concept.16 However, few studies have looked at how such indicators relate to adolescents’ subjective perceptions of their social positioning. After all, friendship groups are important for adolescent development, as they serve as a reference point for evaluating oneself and others.

The researchers asked 114 British adolescents to complete a questionnaire, rating their degree of identification with their friendship group and their self-concept across academic and non-academic domains of self.16 The adolescents also reported their experiences of a variety of developmental tasks: personal tasks such as accepting bodily changes; relational tasks such as establishing close relationships with others; and socio-institutional tasks such as completing school. The developmental tasks were based on prior research findings that adolescents who perceived highest levels of similarity between themselves and other group members reported the most positive experiences of personal and relational tasks.

The researchers found that participants who highly identified with their friendship group reported the highest levels of self-esteem.16 Additionally, the differences between those with low and high identifiers were most pronounced when it came to non-academic self-concepts, as the majority of adolescents’ friendship groups are based in the school environment. High identifiers also reported more positive experiences with personal and relational developmental tasks, as predicted.

The study’s findings have important implications for current understandings of adolescents’ self-evaluations, but also present an issue.16 Several social identity theories claim that group membership contributes primarily to collective, rather than individual, aspects of self. However, this study’s finding that friendship group identification predicts domain-specific self-esteem suggests a need to shift away from collective self-esteem to individual self-esteem, especially as it relates to adolescent friendship groups.

Related TDL Content

Can borrowing bring us together?

You might easily agree to lend your friends some money without much thought. However, some say lending can complicate and damage the quality of friendships. Our editor sat down to discuss financial lending with behavioral scientists Laura Straeter and Jessica Exton. Read through the interview to discover if lending is worth the risk and social norms might play a role.

Social norms

As discussed in the interview above, social norms of mutual care govern friendships, which is why we may feel inclined to lend money to our friends. But what exactly are social norms, and how do they exert their influence on our actions? Take a look through this article outlining the effects of social norms, why they’re important, and how we can sometimes avoid falling prey.


  1. Miller, R. S. (2018). Intimate Relationships. McGraw Hill.
  2. Coan, J. A., & Sbarra, D. A. (2015). Social baseline theory: The social regulation of risk and effort. Current Opinion in Psychology, 1, 87-91.
  3. Adams, R. G., & Blieszner, R. (1994). An integrative conceptual framework for friendship research. Journal of Social and Personal Relationships, 11(2), 163-184.
  4. Marmaros, D., & Sacerdote, D. (2006). How do friendships form? The Quarterly Journal of Economics, 121(1), 79-119.
  5. Johnsen, E. C. (1986). Structure and process: Agreement models for friendship formation. Social Networks, 8(3), 257-306.
  6. Holmberg, D., & Blair, K. L. (2016). Dynamics of perceived social network support for same-sex versus mixed-sex relationships. Personal Relationships, 23(1), 62-83.
  7. Aday, R. H., Kehoe, G. C., & Farney, L. A. (2006). Impact of senior center friendships on aging women who live alone. Journal of Women & Aging, 18(1), 57-53.
  8. Plummer, D. L., Torres Stone, R., Powell, L., & Allison, J. (2016). Patterns of adult cross-racial friendships: A context for understanding contemporary race relations. Cultural Diversity and Ethnic Minority Psychology, 22(4), 479-494.
  9. Shiota, M. N., & Kalat, J. W. (2017). Oxford University Press.
  10. Osgood, D. W., Feinberg, M. E., Wallace, L. N., & Moody, J. (2014). Friendship group position and substance use. Addictive Behaviors, 39(5), 923-933.
  11. Gardner, M., & Steinberg, L. (2005). Peer influence on risk taking, risk preference, and risky decision making in adolescence and adulthood: An experimental study. Developmental Psychology, 41(4), 625-635.
  12. Robinson, K., Garisch, J. A., Kingi, T., Brocklesby, M., O’Connell, A., Langlands, R. L. … & Wilson, M. S. (2018). Reciprocal risk: The longitudinal relationship between emotion regulation and non-suicidal self-injury in adolescents. Journal of Abnormal Child Psychology, 47(2), 325-332.
  13. Cero, I., & Witte, T. K. (2020). Assortativity of suicide-related posting on social media. American Psychologist, 75(3), 365-379.
  14. Hooley, J. M., & Franklin, J. C. (2018). Why do people hurt themselves? A new conceptual model of nonsuicidal self-injury. Clinical Psychological Science, 6(3), 428-451.
  15. You, J., Lin, M. P., Fu, K., & Leung, F. (2013). The best friend and friendship group influence on adolescent nonsuicidal self-injury. Journal of Abnormal Child Psychology, 41, 993-1004.
  16. Tarrant, M., MacKenzie, L., & Hewitt, L. A. (2006). Friendship group identification, multidimensional self-concept, and experience of developmental tasks in adolescence. Journal of Adolescence, 29(4), 627-640.

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