Dr Sarah-Jayne Blakemore of the University College London Institute of Cognitive Neuroscience has found from brain scans that when compared to adults kids from age 8 through the teen years use less of an area of the brain involved in empathy and emotional evaluation when making decisions about the reactions of themselves and others to future hypothetical situations.
Teenagers take less account than adults of people's feelings and, often, even fail to think about their own, according to a UCL neuroscientist. The results, presented at the BA Festival of Science today, show that teenagers hardly use the area of the brain that is involved in thinking about other people's emotions and thoughts, when considering a course of action.
Many areas of the brain alter dramatically during adolescence. One area in development well beyond the teenage years is the medial prefrontal cortex, a large region at the front of the brain associated with higher-level thinking, empathy, guilt and understanding other people's motivations. Scientists have now found that, when making decisions about what action to take, the medial prefrontal cortex is under-used by teenagers. Instead, a posterior area of the brain, involved in perceiving and imagining actions, takes over.
Kids are deficient in empathy and guilt because they haven't yet developed the brain areas needed to fully consider the effects of their actions on others.
Functional Magnetic Resonance Imaging (fMRI) brain scans done while adults and teenagers were asked the same questions showed a different pattern of brain activation in teenagers versus adults.
In the study, teenagers and adults were asked questions about the actions they would take in a given situation while their brains were being scanned using fMRI. For example, 'You are at the cinema and have trouble seeing the screen. Do you move to another seat?' A second set of questions asked what they would expect to happen as a result of a natural event eg. 'A huge tree comes crashing down in a forest. Does it make a loud noise?'
Although teenagers and adults chose similar responses, the medial pre-frontal cortex was significantly more active in adults than in teenagers when questioned about their intended actions. Teenagers, on the other hand, activated the posterior area of the brain known as the superior temporal sulcus – an area that's involved in predicting future actions based on past actions.
Adults can imagine emotional reactions more rapidly than teenagers can.
Participants aged eight to 36 years were asked how they would feel and how they would expect someone else to feel in a series of situations. Adults were far quicker than teenagers at judging emotional reactions – both how they would feel and how a third party might feel in a given situation. For example, "How would you feel if you were not allowed to go to your best friend's party?" or 'A girl has just had an argument with her best friend. How does she feel?"
Brains of kids undergo sharp growth spurts. Therefore the brain undergoes distinct stages of development.
"Whatever the reasons, it is clear that teenagers are dealing with, not only massive hormonal shifts, but also substantial neural changes. These changes do not happen gradually and steadily between the ages of 0–18. They come on in great spurts and puberty is one of the most dramatic developmental stages."
I'd like to see various types of criminals compared to a general adult population. Do some criminals lack fully developed medial prefrontal cortexes? Could neural growth hormones delivered in adolescence to juvenile delinquents steer them away from a life of crime?
"The superior temporal sulcus is usually used in making simple actions, or watching other people make actions," said Dr Blakemore. "We think adolescents are performing this task by simply thinking about the action they're going to take.
"The part of the brain that the adults are using more is involved in much higher level thinking, such as thinking about the consequences of your actions in terms of other peoples' emotions and feelings."
Basically, adults run more complex models of the world that take into account more factors. They also experience feelings resulting from their internal mental simulations of the world and those feelings temper their actions.
Blakemore thinks the law should take into account differences in stages of brain development (and FuturePundit agrees).
The work has implications for the types of responsibility given to adolescents, Blakemore says: “Teenager’s brains are a work in progress and profoundly different from adults. If you’re making decisions about how to treat teenagers in terms of the law, you need to take this new research into account.”
Brains go through quite a transformation in the adolescent years. Kids are not just surly, sullen, rude, cruel, unhappy, and insensitive because they are sexually frustrated or resentful of their low status. Their ability to read the emotions in the faces of others even dips sharply starting around the age of 11. See my post Adolescence Is Tough On The Brain.
|Share |||Randall Parker, 2006 September 10 01:40 PM Brain Development|