We all have that mate who gets a little rowdy after downing a few too many drinks, and it turns out that it comes down to a scientific reaction in the brain. Although drinking and aggression have been linked in the past, without scientific evidence, drunken behaviour has often been put down to the characteristics of the drinker. Alcohol related violence is a huge problem in Australia, with over 59 per cent of assault cases related to consumption according to government statistics.
However, a research team from the University of NSW School of Psychology has identified that alcohol has a chemical effect on the human brain, shutting down the prefrontal cortex [translation: the area of the brain associated with moderating social behaviour and decision making].
"Although there was an overall dampening effect of alcohol on the prefrontal cortex, even at a low dose of alcohol we observed a significant positive relationship between dorsomedial and dorsolateral prefrontal cortex activity and alcohol-related aggression," says Thomas Denson, lead researcher on the project.
The study analysed the effects of alcohol on the brains of 50 men, through the use of MRI scans. Subjects in the experiment were given two drinks each, with half receiving a vodka based drink, and the other half given a non-alcoholic equivalent. Whilst under MRI surveillance, the men were then provoked.
Denson and his team identified that whilst the neuron response to negative stimulus was the same in all subjects, those who reacted aggressively experienced a dip in prefrontal cortex functioning after only two drinks.
"These regions may support different behaviours, such as peace versus aggression, depending on whether a person is sober or intoxicated."
The study supports a growing wave of research that has been linking prefrontal cortex activity to aggression and the effects of alcohol on the brain. The identification of alcohol’s effects will be key in forming strategies to combat trends of violence.