Unawareness of impaired face recognition.

We report investigations of the face processing abilities of SP, a right-handed woman who had suffered a subarachnoid haemorrhage from a right middle cerebral artery aneurysm. Although she could correctly assign visual stimuli to the 'face' category without difficulty, SP performed poorly on all other face processing, tasks, including 'closure' (Mooney faces), perception of facial expression, unfamiliar face matching, and identification of familiar faces. Identification of familiar people from nonfacial cues (names) remained relatively well-preserved, but severe impairments were evident on all face recognition tasks. Her errors mostly involved either failures to find a face familiar at all, or misidentification as another familiar person. In face-name learning tasks, there was evidence of 'covert' recognition of faces she failed to recognize overtly. SP's face processing impairment remained stable across a 20-month period of investigation, yet throughout this period she did not think that she had any problems in face recognition, and continued to show lack of insight into this impairment even when directly confronted with its consequences on formal testing. In contrast, SP showed adequate insight into other physical and cognitive impairments produced by her illness, including poor memory, hemiplegia, and hemianopia. We propose that her lack of insight into her face recognition problems involves a deficit-specific anosognosia, resulting from impairment of domain-specific monitoring abilities.