Summary: While both reactive and proactive aggression in children appears to be genetic, it is the environment the child is exposed to that determines whether the behavior gets worse or better as the child ages, a new study reports.
Source: University of Montreal.
Over the past few months, many local cases of assault and harassment have come to light and been widely discussed in the news, both here and in the U.S. and Europe. Why do people have these types of aggressive impulses? To look for an answer, Stéphane Paquin, a PhD candidate in sociology at Université de Montréal working under the supervision of Éric Lacourse and Mara Brendgen, led a study on 555 sets of twins to compare incidences of proactive and reactive aggressive behaviour. His results demonstrate that, at age 6, both types of aggression have most of the same genetic factors, but the behaviour diminishes in most children as they age. Increases or decreases in aggression between the ages of 6 and 12 appear to be influenced by various environmental factors rather than genetics.
“Too often we forget that aggression is a fundamental part of a young child’s social development,” said Paquin. “Human beings show the highest levels of aggressive behaviour towards their peers between the ages of 2 and 4. As children grow, they learn how to manage their emotions, communicate with others and deal with conflict. They are able to channel their aggressive impulses, whether proactive or reactive.”
Proactive aggression refers to physical or verbal behaviour meant to dominate or obtain a personal advantage at the expense of others, whereas reactive aggression is a defensive response to a perceived threat. While some children only exhibit reactive aggressive behaviours, proactive and reactive aggression are generally closely related.
Twins under the microscope
The study’s cohort of Quebec twins, which included 223 sets of monozygotic twins (with an identical genetic code) and 332 sets of fraternal twins, made it possible to determine whether the individual differences observed in proactive and reactive aggression were due to genetic or environmental factors. The children’s aggressive behaviours were assessed and documented in a report by their teachers at ages 6, 7, 9, 10 and 12. The results of the study also demonstrated that genetic factors influencing aggression at age 6 are different than those associated with changes in behaviour up to age 12. This suggests a common genetic maturation process is taking place, including the maturation of cognitive functions such as planning, decision-making, control and concentration.
With these results, researchers can now move on to study specific social factors associated with changes in proactive and reactive aggression in childhood. “This work will also have a direct impact on clinical practices and prevention programs,” said Paquin. “Our results have revealed the importance of developing different prevention methods for reactive and proactive aggression, specifically by offering support to families and providing interventions in schools.”
He added: “Our findings also corroborate those of other studies, demonstrating that programs designed to prevent reactive aggression should focus on reducing experiences of victimization, whereas those meant to counter proactive aggression should be based on the development of pro-social values.”
Funding: This study was funded by the Social Sciences and Humanities Research Council, the Canadian Institutes of Health Research, the Fonds de recherche du Québec – Santé and the Fonds de recherche du Québec – Société et culture.
Source: Julie Gazaille – University of Montreal
Publisher: Organized by NeuroscienceNews.com.
Image Source: NeuroscienceNews.com image is adapted from the University of Montreal news release.
Original Research: Full open access research for “Heterogeneity in the development of proactive and reactive aggression in childhood: Common and specific genetic – environmental factors” by Stéphane Paquin, Eric Lacourse, Mara Brendgen, Frank Vitaro, Ginette Dionne, Richard Ernest Tremblay, and Michel Boivin in PLOS ONE. Published online December 6 2017 doi:10.1371/journal.pone.0188730
[cbtabs][cbtab title=”MLA”]University of Montreal “Childhood Aggression: Rooted in Genetics, Influenced by Environment.” NeuroscienceNews. NeuroscienceNews, 20 December 2017.
<https://neurosciencenews.com/genetics-environment-childhood-aggression-8216/>.[/cbtab][cbtab title=”APA”]University of Montreal (2017, December 20). Childhood Aggression: Rooted in Genetics, Influenced by Environment. NeuroscienceNews. Retrieved December 20, 2017 from https://neurosciencenews.com/genetics-environment-childhood-aggression-8216/[/cbtab][cbtab title=”Chicago”]University of Montreal “Childhood Aggression: Rooted in Genetics, Influenced by Environment.” https://neurosciencenews.com/genetics-environment-childhood-aggression-8216/ (accessed December 20, 2017).[/cbtab][/cbtabs]
Abstract
Heterogeneity in the development of proactive and reactive aggression in childhood: Common and specific genetic – environmental factors
Background
Few studies are grounded in a developmental framework to study proactive and reactive aggression. Furthermore, although distinctive correlates, predictors and outcomes have been highlighted, proactive and reactive aggression are substantially correlated. To our knowledge, no empirical study has examined the communality of genetic and environmental underpinning of the development of both subtypes of aggression. The current study investigated the communality and specificity of genetic-environmental factors related to heterogeneity in proactive and reactive aggression’s development throughout childhood.
Methods
Participants were 223 monozygotic and 332 dizygotic pairs. Teacher reports of aggression were obtained at 6, 7, 9, 10 and 12 years of age. Joint development of both phenotypes were analyzed through a multivariate latent growth curve model. Set point, differentiation, and genetic maturation/environmental modulation hypotheses were tested using a biometric decomposition of intercepts and slopes.
Results
Common genetic factors accounted for 64% of the total variation of proactive and reactive aggression’s intercepts. Two other sets of uncorrelated genetic factors accounted for reactive aggression’s intercept (17%) on the one hand, and for proactive (43%) and reactive (13%) aggression’s slopes on the other. Common shared environmental factors were associated with proactive aggression’s intercept (21%) and slope (26%) and uncorrelated shared environmental factors were also associated with reactive aggression’s slope (14%). Common nonshared environmental factors explained most of the remaining variability of proactive and reactive aggression slopes.
Conclusions
A genetic differentiation hypothesis common to both phenotypes was supported by common genetic factors associated with the developmental heterogeneity of proactive and reactive aggression in childhood. A genetic maturation hypothesis common to both phenotypes, albeit stronger for proactive aggression, was supported by common genetic factors associated with proactive and reactive aggression slopes. A shared environment set point hypothesis for proactive aggression was supported by shared environmental factors associated with proactive aggression baseline and slope. Although there are many common features to proactive and reactive aggression, the current research underscores the advantages of differentiating them when studying aggression.
“Heterogeneity in the development of proactive and reactive aggression in childhood: Common and specific genetic – environmental factors” by Stéphane Paquin, Eric Lacourse, Mara Brendgen, Frank Vitaro, Ginette Dionne, Richard Ernest Tremblay, and Michel Boivin in PLOS ONE. Published online December 6 2017 doi:10.1371/journal.pone.0188730
