According to the NIH prosopagnosia information page, " Prosopagnosia is a rare neurological disorder characterized by the inability to recognize faces . . . . In some cases it is a congenital disorder, present at birth in the absence of any brain damage. Congenital prosopagnosia appears to run in families, which makes it likely to be the result of a genetic mutation or deletion . . Prosopagnosia can be socially crippling . . . Children with congenital prosopagnosia are born with the disability . . . Their impairment may not be obvious to them or anyone else until they reach adulthood." http://www.ninds.nih.gov/disorders/prosopagnosia/Prosopagnosia.htm Recent studies show that Prosopagnosia is not a rare condition. Two independent estimates indicate that it could affect 2% of the population, a prevalence comparable to amblyopia and dyslexia. Yet, there has been little or no systematic research to understand this common, seriously disabling visual deficit. We will characterize the range of deficits to aid in its diagnosis and to obtain fuller understanding of the condition. We have three main AIMS. First, we will systematically study a large population of prosopagnosic subjects so as to better appreciate its heterogeneity, recognizing at the outset that it comes in pure forms with no other visual deficiencies and in an iconic form where there is a concomitant deficit in visual memory. (Results suggest that these two forms have differing genetic and physiological substrates.) To accomplish this, we will exhaustively test prosopagnosics on many visual functions, assessing the recognition and memory of faces, visual objects and visual scenes. Second, we will more rigorously evaluate several new training regimes where three prosopagnosic subjects have significantly improved on their face recognition capabilities, and we will determine which persons are most likely to benefit from specific training procedures. Third, acknowledging that there are many children suffering from prosopagnosia with no help or understanding of the condition, we will initiate a project to identify children and adolescents with the condition, modifying the above training methods to improve face recognition in these children. PUBLIC HEALTH RELEVANCE Prosopagnosia is a surprisingly common visual deficit characterized by the inability to recognize faces. It can be severely disabling, leading to lost friendships and job opportunities and for some, depression and social isolation. We propose to develop behavioral tests to diagnose and characterize prosopagnosia in adults and in children. In addition, we will determine the efficacy of a new training method to ameliorate the effects of this serious condition.