She starts by telling us about MRIs. There are two types of MRIs to measure brain function, a structural MRI and a functional MRI. A structural MRI takes high resoultion shots of brain and how the gray matter changes during development. A functional MRI is used to take movies of the brain as a person is doing a task. Pictures taken during functional MRIs have shown that the brain continues to develop through adolescents to the early twenty's.
The section of the human brain that goes through the most changes is the prefrontal cortex. This part of the brain is found to be the largest in humans and takes part in decision making, planning, and stopping inappropriate behavior, but this area is still going through development during adolescent stage. The Medial prefrontal is more active when adolescents are making social decision and thinking of other people, this activity decreases as they grow older. The Limbic system is highly hypersensitive to the rewarding feeling you get from risk taking.
When your a child your gray matter increases, peaks when your a teen, then decreases, but that's not something to be worried about. Blakemore tells us that when gray matter decreases it is ridding of unused synapses, and strengthens the ones you do use.
A test Blakemore likes to conduct is to show a photo of a soccer player after he missed a goal, and the crowds behind him. Almost everyone in the photo has the same reaction, even the player himself as he slides on the ground. This test shows how we, as humans, we can tell what a person is feeling, and in this photo it's disappointment. Another test they do at Blakemore's lab involves a computer game in which a person must move the things the man in the game ask them to move. The player is able to see all the objects on the shelves, some of the objects however are blocked from the man. A reduction of errors that happen during the experiment as the age groups get older, but mid-adolescents and adults have the same amount of errors.
Blakemore tells us the environment that the adolescent grows up in will shape their brains, and 40% of teenagers don't have access to secondary school education even though this is when the brain is going through development. Blakemore closes telling the audience that what is sometimes seen as the problem with adolescent (high risk taking, no self control, self-consciousness) actually show that they are developing social skills and gaining an education.