Face and object imagery in congenital prosopagnosia: a case series

It has been reported that congenital prosopagnosics may have a general imagery deficit or an imagery deficit specific to faces. However, much of this evidence is based on self-report questionnaires, rather than experimentally based testing (Grüter et al., 2007, 2009). This study tested face and non-face based imagery in a case series of congenital prosopagnosics, utilising both questionnaire based and forced choice accuracy measures. Our findings indicate that all the prosopagnosics showed impaired face based imagery, which contrasted with normal performance on imagery of objects and colours - a pattern that is consistent with reports of acquired prosopagnosia (Barton, 2008; Michelon and Biederman, 2003). Given all our experimentally based testing indicated face imagery impairments, despite no such problems being seen on self-report questionnaires, we would argue that testing based only on the latter must be interpreted with some caution. Overall, we would advocate that our findings demonstrate a category specific visual imagery impairment in congenital prosopagnosia, such that general imagery skill can be intact in such cases.