Abstract
People with developmental or congenital prosopagnosia (CP) have never learned to adequately recognise faces, despite intact sensory and intellectual functioning. Recent research suggests these individuals can have a deficit restricted to recognising facial identity, with no apparent difficulties recognising facial expressions. These findings are currently being used to infer dissociable cognitive systems underlying facial identity and facial expression recognition. However, this logic only holds if the intact facial processes are achieved via the same mechanisms as controls, rather than compensatory strategies developed to overcome deficits. At present, this is yet to be established. The aim of this project was to determine whether CPs with apparently intact facial expression recognition abilities were using “normal” mechanisms to process this non-identity information from faces, or whether they were using atypical compensatory mechanisms. We assessed the facial expression recognition abilities of a group of adult CPs and a group of age- and sex- matched controls. All of the CPs demonstrated “spared” facial expression recognition abilities on a sensitive battery of facial expression tasks. Given this, we assessed whether the CPs would also show evidence of holistic facial expression perception in a composite task. Composite facial expressions were composed by aligning the top half of one expression (e.g., anger) with the bottom half of another (e.g., happiness). Control participants were slower to identify the expressions in one half of the face when they were aligned rather than misaligned; that is a “composite effect”. Results suggest that the group of CPs also displayed a composite effect for expression. This indicates that CPs and controls use similar mechanisms to perceive facial expressions, and thus that facial identity and facial expression recognition might indeed be dissociable in developmental disorders of face recognition.