We know teenagers can be a bit gawky while they are still learning to coordinate their bodies, says Abigail Baird, a cognitive scientist from Dartmouth College in Hanover, New Hampshire. "We mustn't forget that cognition is doing the same." Teenagers take more risks, because they don't foresee the consequences adults do, she says.

Brain scans taken whilst subjects were analyzing risk situations (eating a salad, swimming with sharks) show that the prefrontal cortex was more active in the teens, suggesting they were making a greater effort to judge the results of each situation. The adults had more basal ganglia activity, pointing to a more automatic response, Baird told a meeting on Law and the Brain at the Institute of Advanced Legal studies, part of University College London.

It was thought that the highest levels of physical and brain maturity were reached by the age of 18. Researchers have identified that the region that inhibits impulsive behaviour is not completely formed until the age of 25. This latest evidence makes adolescence a dangerous time. This could explain the behaviour of many young motorists.
Road accidents are the single greatest cause of accidental death in 16- to 24- year-olds, even though they are at their fittest, with quick reflexes and senses intact.

Young people also take greater risks consistently when their friends are watching. This may be a contributing factor to the appeal of driving too fast, bungee-jumping or reckless skateboarding.

At the same time as the desire to push yourself to the limits arrives, so too does the seeming inability to understand anything your parents may be saying to you. David Skuse at the Institute of Child Health has shown that this inability is the result of a decline in the pubescent brain of boys and girls to read emotions in facial expressions. Whilst boys may be worse at this when younger, by 16 or 17 years they begin to catch up with girls. In the meantime expressions of disapproval may well be ignored!

So, if the adolescent needs more sleep to function effectively, is unable to tell the mood of someone and is less able to predict danger and enjoys risk taking, this might explain some of the challenges facing parents, teachers and youth employers.

Now just one more finding to dwell on: From the Human Brain Mapping Annual Meeting, Toronto, Canada. A small sample of 13 men (age 18 - 26) who played video games for 2 hours every day on average, were scanned using magnetic resonance imaging (fMRI) whilst playing a violent game (navigate a complex bunker, find and kill a terrorist and rescue a hostage). Klaus Mathiak was looking to compare, those parts of the brain activated immediately before fights and less aggressive aspects of the game. He found those parts of the brain activated or shut down were the same as other studies involving simulated violent situations or imagining an aggressive encounter. As you can't replicate these studies using real aggression situations, Mathiak believes this is as close as you can get to understanding responses to the threat of violence, and suggests video games are; "training the brain to react with this same pattern".