Some 56 primary schools were randomly selected in the city of Zurich, Switzerland at the beginning of the so-called z-sproso study in 2004. One feature of the sample group was its heterogeneity, with more than 80 nationalities taking part and all types of social backgrounds being represented: all children entering grade one that year, their parents (during the first year of the study) and teachers were asked to participate in the study and requested to provide information regarding their family, school, personal attitudes as well as violent and problem behaviour every one to two years. More than 90 percent of the original sample, encompassing 1,400 children, participated in at least one interview over a time span of 11 years, i.e. the entire duration of the study. The z-sproso study has already led to more than 70 academic articles.
Social background plays a minor role in explaining violent behaviour
The z-sproso study was designed to answer whether it is possible to predict ten years in advance, which children are most likely to be involved in acts of violence and crime by the time they reach the age of 17. The study focused on aggression and violence, including experiences of victimisation and the participants’ own aggressive behaviour. Contrary to widespread beliefs, social background played a minor role in explaining aggressive or non-aggressive behaviour. "The most important demographic factor is by far gender. Boys show higher levels of most types of antisocial behaviour including physical aggression, bullying and serious offending," Eisner said.
«There is no single cause behind crime or violence. Aggressive behaviour at all ages is always linked to other types of behaviour problems.»
No single cause behind violent behaviour
"A single cause behind a criminal or violent behaviour does not exist. Aggressive behaviour at all ages was linked to other types of behaviour problems such as depressive disorders, ADHD, lack of empathy and non-aggressive conduct problems," Eisner stressed. "The most important long-term predictors of adolescent criminal offenses include early signs of high impulsivity and sensation seeking, a lack of empathy and poor conflict resolution skills. We also found that a history of harsh parenting such as imposing severe corporate punishment and imposing erratic educational methods during childhood is predictive of future adolescent behavioural problems," he added.
Generally, physical aggression evens out to similar levels in both girls and boys as they grow older. In this respect, there are actually almost no differences between boys and girls at the age of 15. "Children acquire new skills between the ages of 7 and 15 enabling them to express themselves better, use foresight and exert self-control," Eisner noted.
Stable family structure and good teacher-student relationship crucial
The study found that children with a stable family situation were significantly less likely to be involved in violence at the age of 17. The effectiveness of two early prevention programmes, one offering parental training and the other, a school-based programme focusing on training social skills, was also analysed – with disappointing results. "Overall, there were no effects from these two preventive programmes on the future reduction of violence," Eisner underlined. What did help though was a good teacher-student relationship. "It does have a major influence on reducing the development of problem behaviour in primary school. Early childhood intervention is an important strategy in reducing future violence," he added.
«Victims of violence are more likely to be perpetrators and vice versa.»
Victims of violence are often perpetrators themselves
In many cases, victims of violence are themselves perpetrators, according to the results of the z-sproso study. "It seems that young victims start thinking about revenge, leading to violence. They also tend to seek out friends who can help them to defend themselves and then enter into a spiral of violence," Eisner said. A strong correlation between watching violent media and pornography, as well as playing violent video games and violent behaviour also emerged in the study. "Consuming violent media is probably not the direct cause of violence, but a facilitator. It provides negative behavioural role models for the youths," Eisner emphasised.
Pocket money is positively correlated with violence
A similar correlation was found between drinking alcohol or consuming illegal drugs, and being violent. "Youths respond to conflicts in an emotionally uncontrolled way when drinking or smoking pot, increasing the risk of violent behaviour," the expert added. A remarkable correlation that will alert all parents with children begging for pocket money or youths badgering about more pocket money is that the larger the amounts of pocket money youths are allocated, the more they are likely to be involved in violent behaviour. "This has been scientifically proved by our study," Eisner said.
«The larger amounts of pocket money the youths are allocated, the more likely they are to be involved in violent behaviour.»
Today’s society far less violent than it used to be
The level of interpersonal violence in Western societies has gradually declined since the Middle Ages. "Medieval society was in many ways a much more violent society than the one we live in, even if our present society has much more destructive technologies at hand," Eisner noted. The level of violence has significantly declined over the past 20 years in most Western countries. "This drop has been documented for assault, bullying, murder and robbery to cite just a few examples," Eisner said. This does not mean the society we live in is that peaceful. "The proportion of people who are victims of violence is still far too high with hate crimes on the rise in some countries. We are also only about to start understanding the severe emotional consequences of violent forms of cybercrime, which seems to be increasing fast," he concluded.