Illustration: Cathy Wilcox.
People prone to aggressive behaviour can reduce their outbursts and control their impulse to fight by using their non-dominant hand or consuming a little sugar, new research has found.
Studies presented at the University of New South Wales found the unusual treatments worked by improving the self-control of aggressive people.
''Self-control is like a muscle, so it requires an energy source - that's the sugar - and practice; that's why we ask people to use their non-dominant hand,'' said psychologist Tom Denson, the study leader and an associate professor at the university.
After the treatments, the aggressive participants felt less desire to act aggressively to others when provoked with an insult or taunt.
Dr Denson said while more research was needed, the therapies could form the basis of interventions for incarcerated violent offenders.
''Ideally, if we could get people to control themselves, we wouldn't have to send them to jail.''
In one series of experiments, university students who identified as aggressive were asked to use their non-dominant hand to perform tasks such as using their computer mouse and picking up a glass. In doing this, they had to override their habitual behaviour, a form of self-control.
Most acts of self-control share neural pathways in the brain, so practising self-control in one area carries over to other domains, Dr Denson said.
After performing the exercise for two weeks, the participants reported feeling less angry and better able to control their outbursts.
Jailed violent offenders were given a sugar drink before being asked to play a computer game against a prisoner in another institution. The winner could then decide how long and how loud the loser was blasted with white noise. While the games were rigged by the investigations so the participants were not really playing anybody, the exercise served as a well-established measure of aggression.
Dr Denson found the prisoners given a sweet drink were considerably less aggressive towards their imaginary opponent than those given a placebo.
''But whether you gave people sugar or had them practise self-control, those who report they get into fights, their aggression went away.''