The hidden evolutionary advantages of the teenage brain

TEENAGERS, eh, what are they like? They have a reputation for being difficult, reckless and self-absorbed, but surely these negative stereotypes can’t be the whole story. Most other animals fly the nest soon after puberty, and none, including our closest primate relatives, has the prolonged adolescence that we do. Why would humans have evolved this peculiar life stage? A closer look at the teenage brain suggests it brings a hidden evolutionary advantage.

The past two decades of research has emphasised that the cerebral cortex, the brain region central to higher processing and cognitive control, continues to develop until our early to mid-20s. By contrast, regions that are sensitive to rewards – including an area called the ventral striatum – are firing on all cylinders by our mid-teens. This has bolstered the narrative that the adolescent brain is noisy and imbalanced, with its overactive reward system causing erratic, sub-optimal decision-making. Early assessments of adolescent cognitive performance seemed to support this. “Sometimes adolescents would do a task well and other times they would not. It was messy,” says Eveline Crone at Leiden University in the Netherlands. However, more recent studies have found that adolescents can be extraordinarily capable – they just need the right kind of task to showcase their skills.

In 2022, for example, Linda Wilbrecht at the University of California, Berkeley, and her colleagues presented 291 volunteers aged between 8 and 30 years old with a computer game in which…