Neuroscience is unraveling the mysteries of the adolescent brain

How would you describe the average teenager? To the majority the following characteristics can come to mind: temperamental, impulsive, risky, prone to succumb to peer pressure.

While it is clear that adolescence is a period of life that is plagued by stereotypes, there is some truth in the clichés. Many neuroscientific studies have established that significant changes occur in the brain during adolescence. And the things that teens are often ridiculed for, such as their risk-taking and vulnerability to peer pressure, are actually rooted in the changes that occur in their brains. There is only one problem with this: many teenagers do not conform to stereotypes.

We all know from personal experience that the way in which adolescents think and act can vary widely depending on the adolescent in question. But, despite this, the vast majority of studies to date have focused on the means: what happens on average with the brain during adolescence or how do teenagers behave and feel on average?

Relying on the means in this way has an important statistical benefit, since researchers are more likely to be able to detect a genuine effect if they averaged their findings among many participants. But the obvious cost is that these general findings do not apply to each and every one.

Understand individual differences

In a recent article, my colleagues and I argue that this must change. From now on, adolescent brain research needs to pay more attention to these important variations among adolescents, which is known in the field as "individual differences."

In addition to documenting that all adolescents are different, we must also begin to understand why this is so. Studies that are already investigating this have shown that both genetics, nutrition, parenting, and mental illness affect the way our brain develops and the way we behave during adolescence. And in our last article, we analyzed three other factors that could affect brain development: socioeconomic status, relationships with peers and culture.

Socioeconomic status is a measure of a person's social and financial position in society, and is often measured by the level of education of their parents and by total family income. Research has already found that your brain develops differently in adolescence depending on your socioeconomic status. But what we still do not fully understand is why. It could be, for example, that being raised in a low-income environment is more stressful or related to different types of nutrition, and that this in turn affects the development of the brain, but more studies are needed on this topic.

Classmates and culture

The type of relationship that teens have with their peers also affects brain activity. Adolescents with a history of harassment, for example, show different patterns of brain activation in the face of certain social information: their brains seem to be more sensitive to the experience of being excluded. For the same reason, having many friends and a history of being loved by classmates also affects brain activation, and can make you more resistant to the development of mental health problems.

All over the world, teenagers also grow up in very different cultures, which affects many aspects of their lives: from how many years they spend studying until they get married and even how much time they spend with their families.

Recently, scientists have been interested in how this could be reflected in the differences in adolescent brains. We already know that adults from different cultures show interesting differences in their activity and brain structure, and this is now beginning to be investigated in adolescents.

Only your average teenager

The reason why most adolescent brain research does not yet consider individual differences is due in part to the fact that the field is only 20 years old, and new areas of research must start with the basics, the means , before trying to understand the nuances.

Adolescent brain research is a relatively new field

There are also practical reasons. The brain imaging technology to date has not been good enough to map exactly how specific factors, such as peer relationships, could affect brain development. Then there is also the fact that to have sufficient capacity to detect reliable findings, large sample sizes are needed.

This means hundreds, sometimes thousands, of teenagers. At the moment, a brain scan costs around € 600 per hour, so the size of the samples is often limited by cost. One way to solve this problem is for scientists to share their data with each other, and this is already beginning to happen.

All the brains are different

Recognizing that all teenagers are different has really important implications for things like education or advertising. If, for example, the way adolescents learn depends on their specific pattern of brain development, then media-based educational strategies will only have limited utility.

In the same way, advertising campaigns for topics such as sexual health, if based on studies that average between participants, will work for some adolescents, but not for others.

The sooner we understand the difference between adolescents, the sooner we can integrate this information into schools and policies. This is important because, after all, there is no average adolescent, and we must remember this as we continue to refine our understanding of the adolescent brain.