This month we delve into the teenage brain, a very frightening place, luckily we have a skilled navigator. New to the blog is Alexandra Highcock. Alexandra has just left school and will begin studying Biomedical Sciences at St Catherine’s College, Oxford in October with a view to hopefully specialise in neuroscience. She has had a long-standing interest in neuroscience, in particular adolescent brain development and hopes to pursue this further in the future. Here she does an excellent job of helping us understand why teenagers take risks.
“There is scarcely a single one of our acts from that time which we would not prefer to abolish later on… but adolescence was the only time when we ever learned anything.”
- Marcel Proust
Do you live with a teenager at home? Or do you remember being one? Ask most people to describe teenage behaviour and it’s often ruefully described by adults as careless and reckless and their behaviour can be a major source of stress and despair for those around them. Even Aristotle described adolescence, over 2300 years ago as a period where, “the young are heated by nature as drunken men by wine.” Although teenagers undoubtedly make poor choices at times, their strong willed risk taking actually has many advantages for their development and transition to adulthood.
Neural development continues from birth until the mid-twenties, and the period of adolescence in particular is a time of extensive neural rewiring and pruning. The remaining neuronal connections become faster and the brain as a whole becomes more efficient (so far so good). This process occurs from the base of the brain (near the spinal cord) to the front and so one of the final areas to develop is the pre-frontal cortex, which is responsible for executive function (planning and decision-making). As a result of this, our ability to moderate our behaviour and integrate memory and experience into our decision-making continues to improve well into our twenties.
So what does this mean for the developing teen brain and body? Teenagers are hypersensitive to pleasure and rewards as the neurotransmitter dopamine release is at its peak during adolescence and this is in turn linked to their decision to make risky choices. This reward system is closely attuned to the brain’s social network, which uses oxytocin, another neurotransmitter that reinforces bonding between mammals. This link results in teenagers strongly associating social interactions with happiness and so therefore constantly seek out social situations. Moreover, teens are more likely to seek out fun and novel experiences in order to experience this extreme ‘buzz’ they feel when taking a new risk. Research has shown that a teenager’s emotional responses are fully functional and in some circumstances, are even more active than an adult’s. However, since the pre-frontal cortex is still developing, adolescents find it harder to filter and control their emotional reactions and so act impulsively. Furthermore, some of the final connections to be fully established in the brain are between the pre-frontal cortex and the amygdala (the emotional centre in the limbic system) leading to a typically less considered approach to events.
There is more to the story than just having a less mature pre-frontal cortex however, since after all, children have an even less well-developed brain and yet still typically take fewer risks than adolescents. This is because decisions are not solely made by a developing pre-frontal cortex but are rather due to competition between the reward processing centre and the control centre in the brain. The key point is that teenagers do understand the risks involved in certain situations, they just value the short-term rewards more and are less able to evaluate the potential outcomes of their actions.
Adolescents clearly perform worse and make less considered judgements in emotional situations and this effect is heightened in front of peers. Teenagers are particularly susceptible to peer-pressure and if you ask them to play something like ‘Grand Theft Auto’ in front of their friends they tended to take more risks and make poorer decisions. On the other hand, when no one else was watching teenagers performed as well, if not better, than adults at the game. Therefore in emotionally neutral situations, teenagers are capable of making just as good decisions as adults but in the heat of the moment when peer pressure and social acceptance come into play, adolescents are far more impulsive.
Although these attributes may not sound helpful and can lead to dangerous outcomes, in an evolutionary context this predisposition to these behaviours was hugely beneficial. Without the desire to explore and try new things, adolescents may never have moved away from their parents. It’s not hard to imagine the impact this could have had on things like global mobility, colonisation and the spread of populations. Additionally, the desire to spend time with one’s peers reinforced intra-generational bonding, leading to strong and self-reliant communities. So its not all bad news and sometimes knowing why teenagers behaves the way they do (when it seems utterly nonsensical to us) can really help to understand them and help put them in situations where their pre-frontal cortex is allowed to take control!