06:42am Sunday 19 November 2017

Kids’ brains are plastic. Will tech make them fantastic?

The adolescent brain is a natural wonder forged by evolutionary forces which have differentiated it from both the child and adult brain. Although “adolescence” was barely acknowledged before the 1900s, and teenagers are often referred to as a modern social invention, our brains suggest otherwise. The teenage brain is distinct in its extraordinary capacity to adapt to the environment around it.

Imagine, then, what might be happening inside the heads of the first generation of “digital natives”? In the United States, teenagers are averaging 8.5 hours a day of learning, playing and interacting via computers, mobile phones and other screen based devices (which jumps to 11.5 hours if you allow for multi-tasking).  In Australia, the comparable average screen time was 7 hours and 38 minutes in 2009.

Digital communication has ushered in more changes in the past 15 years than in the 570 years since Gutenberg’s printing press. And teenagers are the world’s stand-out “early adopters” as the pace of technological change accelerates. It took 38 years for radio to reach its first 50 million people, 20 years for the telephone, 13 years for television, four years for the World Wide Web , 3.6 years for Facebook and even less for Twitter. For Google + it was 88 days.

In terms of evolutionary adaptation, even 10,000 years is merely a blink of an eye. So, our brains did not evolve for reading, which dates back about 5,000 years, let alone spending most of our waking hours sitting down dealing with words and symbols. Today’s remarkable adolescent brain was honed to cope with the demands of learning to survive independently while securing food and shelter, which required rapid, efficient adaptation.

We know this largely because of the relatively recent insights offered by magnetic resonance imaging which show that both the decision-making and reward circuitry of the human brain undergo dramatic changes around puberty.

From then, until the mid to late 20s, human brains are especially “plastic”, which means they can enhance certain pathways and related abilities, and eliminate, or “prune” others depending on what they need to achieve. After the late 20s, however, we do tend to get more set in our (neurological) ways.

Teams of researchers all over the world are currently poised, watching for signs of various technology-driven adaptations, such as the superficial “mile wide, inch deep” thinking of multitasking sidelining the persistence, patience and focus required for in-depth scholarship.

We already have decades of scientific consensus about the perils of multi-tasking; talking on a mobile phone while driving, for example, is as dangerous as driving drunk. That’s because we cannot truly multi-task. The brain is actually constantly switching backwards and forwards between tasks, for which we pay a toll in speed and efficacy.

But, will the “plastic” teenage brain adapt by learning to switch more rapidly and effectively to enable it to do lots of things at the same time with less impairment?

And what of the digital content our teenagers are consuming? Ninety-nine percent of US teenage boys and 94 per cent of girls play online games and the burgeoning global industry is engaging our brain’s rewards system with ever increasing intensity, mostly through violent and sexual themes.

From a neurological point of view online games are stimulating the teen brain’s reward circuitry mainly via the brain chemical dopamine just as puberty is ushering in profound changes in the brain’s reward system driving sexual interest and aggression, evolutionary necessities for survival.

Could such easy access to online games, then, raise the threshold for what our brains deem rewarding? Could the instant gratification available in virtual worlds stunt the next generation’s capacity to work towards long term relationship, work and life goals which do not offer such quick, dopamine-rich returns?

Much current discussion is seeking to characterise the digital revolution as either good or bad when it is probably both. We already know teenage brains are wired to take risks; the neural circuitry involved in impulse control, judgment and long term planning undergoes dynamic changes well into the 20s. That gives parents reason to fret. But, on the other hand risk-taking is an essential launching pad for young people to forge their own paths with optimism, creativity and a sense of the endless possibilities of life.

As one counterintuitive recent trend suggests there isn’t much point in making premature judgments. Teenagers may already be working through powerful emotions online, without potentially negative real world consequences. The soaring popularity of increasingly violent and sexual explicit online games has coincided with a decline, not an increase, in the juvenile murders and violent crime and teen pregnancies.

However, the ways in which the “plastic” teenage brains do adapt to the most ferociously paced change humanity has even seen will certainly define our future.

It could be that we are coddling a generation of shallow thinkers obsessed by superficial Facebook friendships who are too busy staring at screens to bother with saving the world. But, technology is also offering phenomenal educational opportunities, great entertainment and expanding social interactions which will certainly change the world—in ways that those of us with older, less “plastic” brains cannot even imagine. 893

Dr Jay Giedd is an international expert on the adolescent brain. He delivers the keynote speech to the Brain Sciences Symposium at the University of New South Wales today.

This opinion piece first appeared in The Punch.


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