Abstract
Prosopagnosia is a severe impairment in identifying faces that has been associated with deficits in configural face processing—perceiving relations among facial features. Prosopagnosia can result from post-natal occipito-temporal damage (AP—acquired prosopagnosia), or occur with no apparent brain damage and be present from early in life (DP—developmental prosopagnosia).
Here we examined three types of configural face processing in eight adults with DP. The first task measured sensitivity to the first-order relations that define faces (i.e., two eyes above a nose and mouth): classifying Mooney stimuli as either face-like or not. The second task used the Composite Face Task (Hole 1994) to measure holistic processing (gluing the features into a gestalt). The third task measured sensitivity to second-order relations: discriminating faces that differ only in the spacing of features (Mondloch et al., 2002). For comparison we also tested LH, an adult with AP (de Gelder & Rouw, 2000). Prosopagnosics were compared to a normal control group that spanned the same age range (18–73 years).
LH was severely impaired on all three tasks and showed no evidence of any type of configural processing. A different pattern was found for DP. All eight cases performed normally on classifying Mooney stimuli as faces, and all but one showed the composite face effect that indexes holistic processing. However, only one case showed normal processing of second-order relations. The others either showed deficits in distinguishing upright faces that differ in the spacing of the features, or failed to demonstrate the inversion effect for these faces. Although other tests with this cohort indicate that prosopagnosia is not restricted to configural processing deficits, the present results show that AP can be associated with impairment in all three types of configural processing, whereas DP is associated mainly with deficits in one particular type—sensitivity to second-order relations.