"The idea that the brain is somehow fixed in early childhood, which was an idea that was very strongly believed up until fairly recently, is completely wrong. There's no evidence that the brain is somehow set and can't change after early childhood. In fact, it goes through this very large development throughout adolescence and right into the 20s and 30s, and even after that it's plastic forever, the plasticity is a baseline state, no matter how old you are. That has implications for things like intervention programs and educational programs for teenagers."
Sarah-Jayne Blakemore is a leading social neuroscientist of adolescent development. She has reawakened research interest into the puberty period by focusing on social cognition and its neural underpinnings.