First the nose, last the eyes in congenital prosopagnosia: Look like your father looks

Objective: To contribute to the limited body of eye movement (EM) studies of children and family members with congenital prosopagnosia (CP), a task requiring a verbal response for the identification of personally familiar faces was used for the 1st time. Method: EMs were recorded in a father and his son (both diagnosed with CP) and controls (N = 2). In the identification tasks they watched personally familiar faces and distracters and responded by saying the names of the familiar faces or saying "I don't know." Two discrimination tasks were added to distinguish the specificity of the EM pattern for the recognition tasks. In all tasks, faces were presented 1 by 1 until the response onset; thus, the EM pattern was not saturated by overexposure to the stimulus. The 1st fixation position was examined to localize the 1st area of the face attended to. The spatial-temporal fixation pattern was examined to evaluate the attention devoted to specific regions. Results: Both family members were inaccurate and slower than controls in the identification but not the discrimination tasks. In all tasks, they made a number of fixations comparable to those of controls but showed longer fixation durations than controls did. In the identification tasks, they showed poor spatial-temporal distribution of fixations on the eyes and rare 1st fixations on the eyes. Conclusions: Consistent with the literature, both family members showed the typical reduced sampling of the eyes. Nevertheless, our protocol based on explicit verbal responses (which included EM only until response onset) showed that they did not increase the spatial sampling overall by making more fixations than controls did. Instead, they showed longer fixation durations across tasks; this was interpreted as a generalized problem with face processing in affording a more robust sampling of information.