The brain's fusiform face area activates when focusing on faces, and its activation decreases for other objects with directed attention.

“So when people are saying like, "I'm really seeing that face, the details of the face, 'cause I'm paying attention to the face," even though we know their eyes are also looking at and engaged with the contents of the house that's right there, smacked on top, the fusiform face area lights up. And when they're saying like, "Nah, I'm really focused on the house now," we see activation in the fusiform face area decline and other areas of the brain's neurological real estate start to engage.”