Does your brain really have a patch just for faces?

Yes, though how exclusive it is remains debated. A small region called the fusiform face area, or FFA, in the fusiform gyrus of the inferior temporal cortex, is specialized for facial recognition: it is generally agreed to respond more to faces than to most other categories, and it is even active in people blind from birth. What psychologists argue about is why. One camp sees an evolutionary reason, a region dedicated to faces. The other sees expertise: the FFA also responds to familiar objects, so faces may simply be the things everyone is most expert at.

The most vivid evidence for something special comes from a patient known as C.K. After brain damage from a car accident, he developed object agnosia: he had great difficulty recognizing everyday objects, even parts of his own body, yet he performed very well at recognizing faces. A later study found his weak spot. When faces were turned upside down or otherwise distorted, in ways that ordinary people still recognized easily, C.K. could not identify them, which is taken as evidence that the FFA is specialized for faces in their normal orientation.

Justine Sergent first described the region in 1992, and Nancy Kanwisher named it in 1997, arguing that it showed the visual system has domain-specific parts. The expertise camp, championed by Isabel Gauthier, has evidence too. In an adversarial collaboration with Kanwisher, Gauthier's team found some FFA activation when car experts identified cars and bird experts identified birds, later replicated for chess displays and X-rays. And in a study with novel objects called greebles, people's FFA first preferred faces, but responded equally to faces and greebles once they had become greeble experts.

The region even reacts to things that only look like faces. In a 2009 study, objects seen as faces through pareidolia triggered FFA activity after about 165 milliseconds, at a time and place similar to real faces, while other everyday objects did not.