http://blog.wired.com/wiredscience/2009/04/schizoillusion.html
Dima and Jonathan Roiser of University College London wanted to understand why people with schizophrenia aren't fooled. They put 13 schizophrenia patients and 16 healthy control subjects in an fMRI scanner that measures brain activity, and showed them 3D images of concave or convex faces. As expected, all of the schizophrenic patients reported seeing the concave faces, while none of the control subjects did.
