Prosopagnosia is a condition where you cannot recognize faces. Someone who suffers from this cannot identify a person based solely on their face. They do not recognize family or friends, so usually someone with this condition has anxiety with social interactions. Some cannot even recognize themselves. This is not due to an issue with the memory part of the brain. Rather abnormalities of one of the folds in the brain. This condition could result from stroke, traumatic brain injury, or you could be born with it. People who have this disorder use other things to identify people such as clothing, voice or other physical attributes. Many people who have autism also have this disorder which could account for the typical social aversion.