Research of Richard Tremblay

It is commonly said that the peak age for violent behaviour is mid-adolescence. Four decades of research by Professor Richard Tremblay demonstrate that a more accurate statement would be that while the visible consequences of violence are greatest in mid-adolescence, the peak age for aggression and violence in children is 2-3, with those children destined to be the most troublesome offenders in teenage years already distinguished at age 3 by levels of aggression 10 times higher than the most peaceable 30% of toddlers. Tremblay’s research is summarised and has an important message for the most effective age of intervention to reduce violence in society.

In four decades of research into the origins of violent behaviour, Professor Richard Tremblay of the University of Montreal has found solid evidence that the most violent adolescents did not become more violent in their adolescent years; they were already very violent at age 6. In fact comparisons at age 3 show they had much higher levels of violence than other children of the same age, and that they maintained that higher level of violence for the next 10-15 years. At age 29 months (2½ years)  the 17% most aggressive toddlers are already 10 times more aggressive than the 32% least aggressive.

Those who have not learned to control their aggressive reactions by the time they enter the school system enter a vicious circle of negative interactions, where rejection from their peers, because of their aggressive behaviour, leads to more aggression. Such children need intensive interventions to help them learn alternatives to physical aggression at a time when it is developmentally appropriate, i.e. pre-school.

The factors underlying these early differences include the quality of the prenatal and postnatal environments, and gene-environment interactions. Tremblay suggests that society pays a tremendously expensive price for not fostering the quality of early brain development in high risk children, knowing: a) that quality of this crucial organ’s development ensures the quality of behaviour regulation and, b) that chronically violent youth and adults show important cognitive dysfunctions (Tremblay, 2008).

He brings a new perspective to the gene-environment by introducing the scientific term epigenetics. Epigenetics is now suggesting the environment, especially during pregnancy and very early childhood, activates and silences good and bad genes crucial for mental well-being and social adaptation. These studies also indicate that inadequate perinatal environments are not only silencing or activating a few specific genes, but thousands of genes may be affected by maternal stress, inadequate nutrition, obesity, diabetes, alcohol and tobacco use. The prenatal factors that eventually lead to obesity, cardiovascular problems and cancer may also lead to serious mental health problems throughout an individual's life. He argues that a substantial increase in resources to support pregnant women, preschool children and their families would produce major rewards in prevention of mental illness and improvement in health and behaviour of the next generation.