Until recently, it was thought that human brain development was all over by early childhood but research in the last decade has shown that the adolescent brain is still changing into early adulthood. Jim Al-Khalili talks to pioneering cognitive neuroscientist Professor Sarah-Jayne Blakemore who is responsible for much of the research which shows that our brains continue to develop through the teenage years. She discusses why teenagers take risks and are so susceptible to influence from their peers as well as her childhood growing up with the constant threat of attacks from animal rights groups.