I love brain research. That may seem an odd thing to say, but I find recent advances in brain imaging and what it reveals about our brains fascinating. I also love brain research because I’m a parent, and one of the interesting things that brain imaging and research has revealed is how much longer the brain takes to develop than we’d imagined. In particular, the prefrontal cortex – the place where decision making lies – develops far more slowly than we’d thought in general and develops even more slowly in boys than girls in particular. Which helps to explain a lot about the behavior of our adolescent...