We are all familiar with the stereotype of the common childhood bully: a large, brutish boy, shoving and ramming everything that gets in the way of him and the prompt acquisition of all the other kids’ lunch money. But what about the more subtle forms of aggression such as social exclusion or rumour spreading? Like physical aggression, social aggression can have devastating effects on the victims, including anxiety, depression, and even thoughts of suicide.

Physical Aggression: Decreases With Age and "Unlearned" Over Time

Physical aggression (e.g., hitting, pushing, or grabbing others’ property) seems to be a rather natural behavior in toddlers, although children differ considerably with respect to the frequency and intensity with which such behavior is enacted. Over the course of early and middle childhood, most children learn to regulate their behavior and to use more socially acceptable strategies when dealing with their peers. Not all children learn to inhibit their physically aggressive behavior, however, and about 15% percent of children remain on a stable and high trajectory of physical aggression from infancy throughout the preschool years and beyond (1). Moreover, although most children seem to “unlearn” physical aggression in favor of more socially acceptable alternatives, these alternatives do not always include positive social behaviors such as negotiation or sharing. Indeed, at approximately four to five years of age some children begin to display socially aggressive behavior (2). The use of this type of social aggression then gradually increases with age and seems to reach a peak in adolescence (3). The nature of social aggression also becomes increasingly diverse as children mature, with aggressive acts such as public slander carried out via e-mail, text messages, or chat rooms (4).

Social Aggression: Increases With Age and Learned Over Time

The decrease in physical aggression and the increase in social aggression that researchers have documented from early childhood through mid-adolescence suggest that social aggression may be more of a learned behavior than physical aggression. Support for this notion comes from research on the relative influence of genetic factors versus environmental factors in terms of behavior. Findings from this type of research suggest that at least 50% of differences between individuals in physical aggression during childhood are attributable to genetic influences whereas the other 50% are due to environmental influences. In other words, physical aggression in children seems to be equal parts nature and nurture. Although social aggression appears to be influenced by the same genes that influence physical aggression, the overall effect of heredity on social aggression is relatively small (5). Instead, social aggression seems to be mostly shaped by a child’s environment. It is also important to note that the environmental influences that determine social aggression seem to be different from the environmental influences that determine physical aggression (5). Environmental Influences on Physical Aggression Explained What are the environmental influences that promote aggression? Research suggests that the family context in general, and parental behaviors in particular, are among the main environmental contributors to child physical aggression. Thus, a lack of parental monitoring, harsh disciplinary practices (e.g., hitting, shouting) toward the child, and a lack of warmth have been shown to foster physically aggressive behavior in the child, and these effects may be exacerbated in families living in already chaotic circumstances (6). Notably, these environmental influences are found even when accounting for genetic effects on physical aggression. Children who are exposed to a significantly stressful family environment at a young age are less likely to learn how to regulate their behavior and more likely to show continuously high levels of physical aggression.

Environmental Influences on Social Aggression: Learned Through Parents and Peers

Parental influences on social aggression have not been thoroughly studied. Recent evidence suggests, however, that one way children may learn socially aggressive behavior is from observing parents’ use of manipulative tactics such as love withdrawal or the use of guilt as punishment – either towards each other or towards the child (7). Parents may also foster social aggression in their child without ever using this type of behaviour themselves. Studies show that adults consider social aggression to be less serious than physical aggression and, as a result, are less likely to intervene in these specific circumstances (8). If they do intervene, they are less inclined to discipline the socially aggressive child responsible for the harmful situation (9).

Of course, parents are not the only source of environmental influence on child behaviour, and perhaps one of the most important additional social influences on children’s physical and social aggression comes from their peer group. Thus, findings from a recent study of genetic versus environmental influences on behaviour indicate that children who are already genetically inclined toward physical aggression are far more likely to be physically aggressive if they also hang out with physically aggressive friends (10). It is important to note, however, that children who have a socially aggressive peer group are likely to be socially aggressive themselves, whether or not a genetic predisposition is present.

Moving Beyond a Stereotypical View of Bullying

Children with a genetic disposition to physical aggression may be less receptive to punishment and this imperviousness may be especially pronounced in the company of physically aggressive friends who model and reinforce this type of behavior. In contrast, social aggression involves rather subtle behavior with less risk of retribution. Exposure to highly socially aggressive friends may thus foster socially aggressive behavior even in children who do not have any pre-existing genetic liability for aggression.

Taken together, these research findings suggest that socialization efforts by parents and educators should not merely focus on reducing physical aggression. To prevent children from simply replacing one type of aggression with another, adults need to make it clear that social aggression is as unacceptable as physical aggression. To do so, adults should avoid setting bad examples themselves and discourage malicious gossip and other socially aggressive behaviour in children’s interactions with peers. Since the environment is especially instrumental in shaping social aggression in young children, such socialization efforts may help curb the increase of this type of behaviour in later years.


  1. Côté, S., Vaillancourt, T., Barker, E. D., Nagin, D., & Tremblay, R. E. (2007). The joint development of physical and indirect aggression: Predictors of continuity and change during childhood. Development and Psychopathology, 19, 37–55.
  2. Vaillancourt, T., Miller, J. L., Fagbemi, J., Côté, S., & Tremblay, R. E. (2007). Trajectories and Predictors of Indirect Aggression: Results From a Nationally Representative Longitudinal Study of Canadian Children Aged 2–10. Aggressive Behavior, 33, 314-336.
  3. Bjorkqvist, K., Lagerspetz, K. M. J., & Kaukiainen, A. (1992). Do girls manipulate and boys fight? Developmental trends in regard to direct and indirect aggression. Aggressive Behavior, 18, 117–127.
  4. Li, Q. (2006). Cyberbullying in Schools. School Psychology International, 27, 157-170.
  5. Brendgen, M., Dionne, G., Girard, A., Boivin, M., Vitaro, F., & Pérusse, D. (2005). Examining Genetic and Environmental Effects on Social Aggression: A Study of 6-Year Old Twins. Child Development, 76, 930-946.
  6. Moffitt, T. E. (2005). The New Look of Behavioral Genetics in Developmental Psychopathology: Gene-Environment Interplay in Antisocial Behaviors. Psychological Bulletin, 131, 533-554.
  7. Casas, J., Weigel, S. M., Crick, N. R., Ostrov, J. M., Woods, K. E., Yeh, E. A., Huddlestone-Casas, C. A. (2006). Early parenting and children's relational and physical aggression in the preschool and home contexts. Applied Developmental Psychology, 27, 209–227.
  8. Craig, W. M., Henderson, K., & Murphy, J. G. (2000). Prospective Teachers' Attitudes toward Bullying and Victimization. School Psychology International, 21, 5-21.
  9. Yoon, J. S. & Kerber, K. (2003). Bullying: Elementary teachers' attitudes and intervention strategies. Research in Education, 69, 27-35.
  10. Brendgen, M., Boivin, M., Vitaro, F., Bukowski, W. M., Dionne, G., Tremblay, R. E.., & Pérusse, D. (2008). Linkages Between Children’s and Their Friends’ Social and Physical Aggression: Evidence for a Gene-Environment Interaction? Child Development, 79, 13-29.

Biographical information

Dr. Mara Brendgen is an associate professor at the Psychology Department of the University of Quebec at Montreal. Dr. Brendgen conducts research on the interplay between individual, family-related, and peer-related factors in the etiology of aggression and victimization among children and adolescents.