Abstract
Developmental prosopagnosia (DP) is defined by severe face recognition difficulties due to the failure to develop the visual mechanisms necessary for processing faces. The Two-Process Theory of face recognition (Morton & Johnson, 1991) implies that DP could result from a failure of an innate face detection system and that this failure could prevent an individual from then developing or tuning higher-level processes for face recognition (Johnson, 2005). Work with adults indicates some individuals with DP have normal face detection whereas others are impaired. However, face detection has not been addressed in children with DP, even though their results may be especially informative because they have had less opportunity to develop strategies that could mask face detection deficits. We therefore tested the face detection abilities of seven children with DP with two tasks. Children were identified as being DP if they reported real-life difficulties with face recognition and scored greater than two standard deviations below age-matched controls on the Cambridge Face Memory Test – Kids and/or the Dartmouth Face Perception Test. One face detection task required participants to find faces among non-faces (objects, scenes, etc.), and the other required participants to find two-tone faces among scrambled face parts. Four of the seven DP children were impaired at face detection to some degree (i.e. abnormally slow, or failed to find faces) while the remaining three children had normal face detection. Hence, the cases with impaired detection are consistent with the Two-Process Theory account suggesting that DP could result from a failure of face detection. However the cases with normal detection implicate a higher-level origin. The dissociation between normal face detection and impaired identity perception also indicates that these abilities depend on different neurocognitive processes.
Meeting abstract presented at VSS 2015