Who is an adolescent?

Our research shows that adolescence is a critical developmental period. Children’s experiences and explorations during this time shape their cognitive skills (including critical thinking and decision-making) and social and emotional skills (including moral reasoning).

Adolescence also lasts longer than we tend to think. Important brain development begins during late childhood, around eight to nine years. Intense changes then follow during early adolescence (ages ten to 14). But these changes continue well into the twenties, and full cognitive and emotional maturity is not usually reached until around age 24.

However, everyone’s brain matures at a different rate. That means there is no definitive age at which we can say humans have reached “adult” levels of cognitive maturity. What we do know is the period of early adolescence is critical.

What does puberty do to the brain?

Puberty is a defining feature of early adolescence. Most of us are familiar with the changes that occur in the body and reproductive systems. But the increase in puberty hormones, such as testosterone and oestrogen, also triggers changes in the brain. These hormones increase most sharply between ten and 15 years of age, although gradual changes continue into the early twenties.

Puberty hormones change the structures in the brain that process emotions, including the amygdala (which encodes fear and stress) and ventral striatum (which is involved in reward and motivation).

This makes adolescents particularly reactive to emotional rewards and threats. Our research has shown the brain’s sensitivity to emotions increases throughout early adolescence until around 14 or 15 years old.

At the same time, changes in puberty have been linked to increased sensation-seeking and impulsive behaviours during early adolescence.

This context is crucial when we discuss children’s behaviour in the ten to 14 age range. The way their brains change during this period makes them more sensitive and responsive to emotions and more likely to seek experiences that are new and intense.

How do adolescents make decisions?

The emotional context of puberty influences how younger adolescents make decisions and understand their consequences.

Decision-making relies on several basic cognitive functions, including the brain’s flexibility, memory and ability to control impulses.

These cognitive abilities – which together help us consider the consequences of our actions – undergo some of the steepest development between ages ten and 14. By age 15, the ability to make complex decisions has usually reached adult maturity.

But adolescents at this age remain highly susceptible to emotions. So, while their brains may be equipped to make complex decisions, their ability to think through the consequences, weighing up costs and benefits, can be clouded by emotional situations.

For example, research has shown that 13-14-year-olds were more distracted from completing a task and less able to control their behaviour when they viewed images that made them feel negative emotions.

The social world of teenagers also has a significant impact on how they make decisions, especially in early adolescence. One study found that while older adolescents (aged 15-18) are more influenced by what adults think when weighing up risk, adolescents aged 12-14 look to other teenagers.

Experiments have also shown that adolescents aged 12-15 make riskier decisions when they are with peers than by themselves. Their brain responses suggest that they experience a greater sense of reward in taking those risks with peers.

How do teens understand the consequences of their actions?

The concept of criminal responsibility is based on whether a person is able to understand their action and know whether it is wrong.

Moral reasoning—how people think about right and wrong—depends on the ability to understand another person’s mental state and adopt their perspective. These skills are developed throughout adolescence.

Research suggests that adolescent brains may take more effort to process “social” emotions, such as guilt and embarrassment, compared to adults. This is similar to how they make moral judgements. This evidence suggests that teenage brains may have to work harder when considering other people’s intentions and desires.

Young adolescents have the cognitive ability to appreciate that they made a bad decision, but it is more mentally demanding. And social rewards, emotions and the chance to experience something new all have a strong bearing on their decisions and actions in the moment — possibly more than whether it is right or wrong.

Early adolescence is critical for the brain

There are also a number of reasons adolescent brains may develop differently. This includes various forms of neuro disability such as acquired brain injury, fetal alcohol spectrum disorder, attention-deficit hyperactivity disorder (ADHD) and intellectual disability, as well as exposure to trauma.

Teenagers with neurodevelopmental disorders will likely cope differently with decision-making, social pressure, impulse control and risk assessment and face extra difficulties. Across the world, they are disproportionately incarcerated.

In Australia, Indigenous children and adolescents are incarcerated in greater numbers than their non-Indigenous peers.

Each child matures differently, and some face extra challenges. But for every person, the period between ten and 14 is critical for developing the cognitive, social and emotional skills they’ll carry throughout their lives.

Susan M. Sawyer, Professor of Adolescent Health, The University of Melbourne; Director, Royal Children’s Hospital Centre for Adolescent Health, The University of Melbourne and Nandi Vijayakumar, Research Fellow, School of Psychology, Deakin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.