How is the MRI used in Steele's study of human behavior as noted in the nonfiction book, Whistling Vivaldi?

Magnetic Resonance Imaging is a way of detecting brain activity, by measuring blood flow and the amount of iron in the blood. As a social psychologist, Steele is usually only able to study people’s behaviors, and what is visible from the outside. Follow up studies have been able to confirm and expand upon his and his colleagues’ findings by using MRIs and other physiological measures to look at what is actually going on inside the brain and the body. While Steele’s initial studies tell us what is going on when someone faces pressure from a stereotype, MRI studies help clear up the how and why.