Lead
"Suddenly all they want to do is have secret conversations with their friends — nothing to tell us anymore." "They play by their own private rules and are way too sensitive about being left out." These are observations many parents make around ages 9–10.
This period is sometimes called the "gang age" in Japanese child development writing — a term whose sound in Japanese, as in English, might conjure images of trouble. In the developmental science literature, however, it describes a stage children necessarily pass through in acquiring social competence. The shift toward prioritizing peers over parents is not a regression. It is, from a developmental standpoint, progress.
This article examines what same-sex peer-group formation means, why it happens at this age, and how parents can find a useful distance from it.
What the Gang Age Actually Describes
Its Place in Developmental Stage Theory
In Erikson's theory of psychosocial development: Erik Erikson's theory that personality develops through a series of stages, each defined by a central social-emotional tension to be worked through, ages 6–12 fall in the stage of industry versus inferiority [1]. Within the institution of school, children repeatedly test whether they can achieve things. The peer group is one of the primary arenas for that testing. Moral rules and social role assignments are internalized not through instruction from adults but through negotiation and conflict with peers.
Harter's research shows that self-concept is rapidly refined during middle childhood [2]. The answer to "what kind of person am I?" shifts its center of gravity from the self-image formed at home to the self-image formed within the peer group.
The Universality of Same-Sex Peer Grouping
In a comparative observational study conducted across six cultural contexts — the United States, Mexico, India, the Philippines, Okinawa, and Kenya — Whiting and Edwards found that the proportion of play with same-sex peers increased during ages 7–10 in all six cultures [3]. This tendency is not specific to any one cultural setting; it appears to be a broadly shared feature of human development.
Rubin et al.'s longitudinal review shows that during this period, scores on "sense of belonging to a group" rise, and peer acceptance becomes a primary constituent of self-esteem [4].
What Harris's Group Socialization Theory Suggests
"The Peer Group Is the Primary Socializer"
Harris's group socialization theory: Judith Rich Harris's controversial theory arguing that peer groups, not parents, are the primary force shaping children's personality and behavior outside the home, published in 1995, generated significant debate in developmental psychology [5]. The central argument is that children's social behavioral patterns are shaped more by the peer group than by the home environment.
This argument draws on data from twin studies and adoption studies. Shared home environment — parenting style, family values — turns out to exert less influence on personality formation than commonly assumed, while genetic temperament and peer-group influence explain more.
The theory has, of course, attracted criticism. There is substantial pushback asserting that the quality of the parent-child relationship (attachment security, for instance) clearly does influence child development. Harris's contribution is better read as a corrective — "we have been systematically underestimating peer-group influence" — rather than as a claim that parenting has no effect [4].
Redefining What Parents Do
The practical implication of Harris's framework is that the parent's role shifts. After ages 9–10, trying to stop children from turning toward the peer group is working against the direction of development. The shift is from "what values and skills do I transmit to my child?" to "what environment and groups does my child have access to?" Parents become environment designers rather than primary instructors.
The home remains important, but in a different way: it is the place the child can return to. The function of home in this period is as a place where a child can land when peer relationships go wrong — where they can be honest, where they don't have to perform. That is the main thing the home does during these years.
Inclusion and Exclusion at the Group Entry Point
The same-sex grouping phase is also the time when exclusion becomes more common. Rubin et al. show that around ages 9–10, peer groups begin to develop social hierarchies, and boundaries around "who belongs" become sharper [4].
Parents should keep in mind that "moving around in groups" and "not being excluded from groups" are different things. A child who is choosing solitude and a child who has been pushed out require very different responses. (The distinction is covered in the companion article on aloneness.) Signs that warrant concern include repeated collective exclusion, sustained mockery, hiding of a specific child's belongings, and targeted harassment — situations that call for coordinated response with the school rather than watchful waiting.
Putting It Into Practice
Create moments when you deliberately choose not to ask. Attempting to track everything that happens in the peer group will cause children to close down information-sharing. Replacing "how was today?" with "if something's bothering you, I'm here" — maintaining an open posture rather than an interrogative one — tends to keep the channel open.
Make sure there is a physical space where children can spend time together. Children being able to gather somewhere after school is one of the conditions under which healthy group formation proceeds.
Connect screen management to this developmental transition. Digital communication, which begins entering children's lives around this age, is a natural extension of peer-group dynamics. Designing usage rules — time limits, acceptable group messaging practices — with the child is more productive than imposing them unilaterally, and this is a good moment to establish that collaborative design.
Maintain the ordinary rhythms of home as the place that stays constant. The most important thing a parent can do during this period may be sustaining the everyday texture of home life — so that on days when peer relationships go badly, the child has somewhere to come back to.
Summary
The "friends first, parents second" shift at ages 9–10 is developmental progress, not a step backward. Same-sex peer grouping is a cross-culturally documented universal pattern, occurring in the period when children are building their social selves and moral frameworks alongside their peers.
During this period, the parent's role evolves from transmitter of knowledge and values toward designer of environments and keeper of a safe home base. Consciously accepting that shift is what makes it possible to support children's group formation rather than working against it.
The growing number of things you don't know is also evidence that trust is being built.
References
- Erikson EH. Childhood and Society. New York: Norton; 1950.
- Harter S. The Construction of the Self: A Developmental Perspective. New York: Guilford Press; 1999.
- Whiting BB, Edwards CP. Children of Different Worlds: The Formation of Social Behavior. Cambridge: Harvard University Press; 1988.
- Rubin KH, Bukowski WM, Parker JG. Peer interactions, relationships, and groups. In: Damon W, Lerner RM, eds. Handbook of Child Psychology. 6th ed. Hoboken: Wiley; 2006. p. 571–645.
- Harris JR. Where is the child's environment? A group socialization theory of development. Psychol Rev. 1995;102(3):458–489. doi:10.1037/0033-295X.102.3.458. PMID: 7624455
- Bukowski WM, Motzoi C, Meyer F. Friendship as process, function, and outcome. In: Rubin KH, Bukowski WM, Laursen B, eds. Handbook of Peer Interactions, Relationships, and Groups. New York: Guilford; 2009. p. 217–231.