How teenagers become human

How teenagers become human
Inventing Ourselves: The Secret Life of the Teenage Brain

by Sarah-Jayne Blakemore (Penguin Ireland, €16)



In a congenial, fascinating book neuroscientist Sarah-Jayne Blackmore explores the wondrous malleability of the human brain. The brain is continually changing and adapting. If I took up juggling, the part of my brain that co-ordinates the movement of my limbs would expand, as would the region responsible for orientation and spatial awareness if I were to start driving a taxi.

The term ‘adolescent’ – a recent coinage – describes that distinct phase between childhood and adulthood, when young people turn ‘changeful and fickle’ as Aristotle put it.

Blakemore explains teenage capriciousness and willingness to take risks in terms of the uneven growth of the brain during adolescence: the area that restrains and inhibits us develops more slowly than the region that produces the sensations of pleasure we experience after taking a chance, or trying something new.


Warning adolescents about the long-term risks of smoking, drinking or taking drugs is close to pointless, Blakemore argues. Adolescents lack a developed understanding of the consequences of their actions. They don’t have a store of cautionary memories, unlike adults, who know what a hangover feels like, and how difficult it is to give up the gaspers.

In relation to smoking Blakemore suggests that parents talk to their teenagers about bad breath, malodorous clothes and stained teeth: they might usefully tell people who want their peers to consider them cool that smoking makes you smell horrible.

Adolescents are receptive beings. As their brains develop, they become more aware of the feelings of others, more empathetic, more sensitive. They listen to socially useful messages, about bullying and its prevention for instance.

Teenagers might learn more efficiently if schools opened and closed later, Blakemore suggests. As children enter adolescence their circadian rhythm – body clock – changes: their brains prefer to remain active longer into the evening, and rest longer in the mornings.

This altered circadian rhythm also explains why teenagers like a lie-in at weekends: they’re simply catching up on missed sleep.

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