Abstract
It has long been presumed that face-space coding and holistic processing are primary determinants of successful face recognition. Here, however, we present a case of a severe developmental prosopagnosic who showed normal face-space coding and holistic processing. Subject SP (a 23 year-old female) demonstrated severe face perception and face memory deficits, scoring 2.24 – 6.87 SD below the mean on the Cambridge Face Perception Test, the Cambridge Face Memory Test, and the MACCS Famous Face Test 2008. Her deficits appeared to be face-specific: performance was well within the normal range on a general intellectual test (Raven), a word memory task, the Birmingham Object Recognition Battery, and the Cambridge Car Recognition Test. To investigate SP's face-space coding, we used a wide range of face adaptation aftereffect experiments. Compared to controls, SP showed normal eye-height, expanded/contracted, and identity aftereffects for faces; she also showed normal expanded/contracted aftereffects for side-views of horses. Importantly, we ruled out the interpretation that SP's normal face aftereffects arose from object-general representations: exactly like controls (Susilo, McKone, & Edwards, VSS 2009), SP showed weak transfer of aftereffects between a vertically-distorted T-shape and test faces varied in eye-height. To investigate holistic processing, SP completed three composite tasks (one naming, two same/different) with three different sets of faces. She demonstrated normal composite effects for upright faces. Crucially, she showed no composite effect for inverted faces, ruling out the possibility that the upright effect was driven by a general global attentional bias. The case of SP suggests that face-space coding and holistic processing alone may not be sufficient to explain face recognition, and speaks to the possibility of other important determinants behind successful face recognition performance.
Supported by: Australian Research Council DP0450636 and DP0984558 to EM scholarship support from ANU Centre for Visual Sciences and overseas student fee waiver from ANU Department of Psychology to TS.