An elderly man was admitted to a hospital. The staff soon noticed that he became agitated when walking by pictures hanging on the walls. These were framed prints encased in glass. When passing by the picture, he would catch a reflection of himself and then turn and start yelling, “Get away from me! Leave me alone!” He would ask the nurses plaintively, “Why does that man keep following me?”

This man suffered from a disorder known as prosopagnosia, which refers to the inability to recognize faces. This bizarrely specific disorder is due to lesions in the fusiform gyrus, a multimodal association region that is located at the bottom of the temporal lobe. The fusiform gyrus integrates perceptual information about faces into recognizable wholes. When this region is damaged, the person cannot perceive faces as a recognizable whole but only as a collection of visual parts. Some readers may be familiar with this disorder from Oliver Sacks’s book The Man Who Mistook His Wife for a Hat.