ABSTRACT
The observation that the perception and recognition of faces can be impaired in neurological patients can be traced back to the ancient Greeks (Thucidydes II, 47–50). This Greek general who fought in the Pelopenesian Wars described in his second book the strange behavior of soldiers who survived the plague. He observed, among other impairments, severe memory problems and, in some, an inability to recognize friends. Neurological case studies published in the second half of the nineteenth century often mention problems in this domain in patients who have suffered neurological disease (e.g., Charcot, 1888; Wilbrand, 1892). Hoff and Potzl (1937) suggested that face recognition might be a separate function that can be impaired after brain injury. However, it was not until 1947 that the German neurologist Bodamer published a report on a number of patients who experienced a particularly selective difficulty in recognizing faces. Bodamer named the condition “prosopagnosia” with reference to the Greek prosopon (face) and a-gnosis (without knowledge). Having this condition was, obviously, an extremely unpleasant experience. When Bodamer asked his patient (case 1) to inspect his own face in the mirror: “He first explored the mirror as if it were a picture, corrected himself, stared in the mirror for a long time as if he had a completely unknown object in front of him and subsequently stated that he did see a face, including all the features which he described, he also knew it was his face. However, he did not recognize it as his own. It could just as well be someone else’s or even a woman” (Bodamer, 1947, p. 15). As far as we know now, all prosopagnosic patients know when they are looking at a face, and they can identify and describe separate features such as the eyes and mouth (Blanc-Garin, 1984). Therefore, they clearly know that they are looking at a human face. However, the face has lost its value as a cue for identification of a person. In severe cases, even the faces of family members and close friends and sometimes the patient’s own face seen in a mirror are unrecognized. The patient studied by MacRae and Trolle (1956) commented that on several occasions, while looking in the mirror, he had grimaced or stuck his tongue out, “just to make sure” (p. 96). Not even a vague feeling of familiarity, when the patient is looking at a known face, survives.
