Children who have a positive relationship with their primary school teacher go on to be less aggressive as teenagers, a Cambridge University study has found.
The study found the key time for this to happen was around the age of 10 to 11 years old, with a good pupil-teacher relationship markedly influencing the development of "pro-social" behaviours such as co-operation and altruism, as well as significantly reducing problem classroom behaviours such as aggression and oppositional behaviour.
Beneficial behaviours resulting from a positive teacher-student relationship when a child is on the cusp of adolescence lingered for up to four years, well into the difficult teenage years, research found.
Researchers found that students with a more positive relationship with their teacher displayed towards peers, on average, 18% more pro-social behaviour (and 10% more up to two years later), and up to 38% less aggressive behaviour (and 9% less up to four years later), over students who felt ambivalent or negative toward their teacher.
Positivity toward their teacher also resulted in students displaying an average of 56% less "oppositional defiant" behaviour: such as argumentativeness and vindictiveness toward authority figures. This was still reduced by 22% up to three years later.
In fact, the researchers found the beneficial effect on behaviour was as strong, if not stronger, than that of established school-based "intervention programmes" such as counselling and other anti-bullying therapies.
The importance of good teacher relationships on infant behaviour was already known, and programmes have been designed to help pre-school teachers improve relationships with pupils, which in turn improves pupil behaviour.
Researchers say the latest results suggest that developing similar programmes for those who teach students in early adolescence has the potential to promote better classroom behaviour in schools that may otherwise rely more on exclusionary practises - such as detentions, or being sent out of class - to manage student behaviour.
"Teachers play an important role in the development of children," said the study's lead author Dr Ingrid Obsuth.
"Students who feel supported tend to be less aggressive and more pro-social, and we now have evidence that this is the case from pre-school right through to adolescence.
"Educational and school policies should take this into consideration when supporting teachers in fostering their relationships with students."
The research was conducted by members of the violence research centre at Cambridge's Institute of Criminology, along with colleagues from ETH Zurich and the University of Toronto. The findings are published in the Journal Of Youth And Adolescence.
The latest study analysed data from more than 1,000 students randomly sampled across 56 schools in Zurich, who formed part of a previous study.
Only students who experienced a change of teacher between ages nine and 10 were used for the study, with data gathered from teachers, students and their parents on an annual and later biannual basis.
Interview from interviews and surveys was used to score the children across 100 different characteristics or experiences that could potentially account for good or bad behaviour - from background to past behaviour, parenting to student and teacher genders.
They then matched students in pairs with highly similar scores in all respects except one: how they felt about their teacher, and how the teacher felt about them.
Researchers said a student's perception of the relationship was most important for behaviour.
Cambridge's Prof Manuel Eisner, senior author on the study, said: "Most adults remember some teachers that they admired and that fit their learning needs, and others that they felt hard done by.
"This is not necessarily only because they have more or less supportive teachers.
"Each child will respond differently to a teacher's style and personality.
"Our study shows that once a child develops an impression of a teacher, one way or the other, it can have significant long-term effects on their behaviour."
Dr Obsuth added: "Ideally, building healthy and supportive teacher-student relationships would become part of the curriculum in teacher training and intervention programmes as a way of improving adolescent well-being."