Does Prosopagnosia Take the Eyes Out of Face Representations? Evidence for a Defect in Representing Diagnostic Facial Information following Brain Damage

Abstract

One of the most impressive disorders following brain damage to the ventral occipitotemporal cortex is prosopagnosia, or the inability to recognize faces. Although acquired prosopagnosia with preserved general visual and memory functions is rare, several cases have been described in the neuropsychological literature and studied at the functional and neural level over the last decades. Here we tested a brain-damaged patient (PS) presenting a deficit restricted to the category of faces to clarify the nature of the missing and preserved components of the face processing system when it is selectively damaged. Following learning to identify 10 neutral and happy faces through extensive training, we investigated patient PS's recognition of faces using Bubbles, a response classification technique that sampled facial information across the faces in different bandwidths of spatial frequencies [Gosselin, F., & Schyns, P. E., Bubbles: A technique to reveal the use of information in recognition tasks. Vision Research, 41, 2261-2271, 2001]. Although PS gradually used less information (i.e., the number of bubbles) to identify faces over testing, the total information required was much larger than for normal controls and decreased less steeply with practice. Most importantly, the facial information used to identify individual faces differed between PS and controls. Specifically, in marked contrast to controls, PS did not use the optimal eye information to identify familiar faces, but instead the lower part of the face, including the mouth and the external contours, as normal observers typically do when processing unfamiliar faces. Together, the findings reported here suggest that damage to the face processing system is characterized by an inability to use the information that is optimal to judge identity, focusing instead on suboptimal information.

Atypical information-use in children with autism spectrum disorder during judgments of child and adult face identity

“…There is a broad consensus that efficient (i.e., in some sense optimized) information use and flexible processing strategies support typical face expertise, but this link is yet to be empirically tested. It is true that evidence of atypical strategic information use in populations with face reading difficulties are consistent with this notion, for example, autism spectrum disorder (e.g., current study, also Neumann et al, 2006; Spezio et al, 2006, 2007) and prosopagnosia (e.g., Caldara et al, 2005; Xivry et al, 2008). Still these groups demonstrate other, potentially influential visuoperceptual and/or social atypicalities, making it an interesting open question whether this association truly holds and/or extends to the typical population.…”

“…Here, they relied significantly upon information in the eye region (particularly the left side eye) and the mouth region, as reported in Butler et al (2010), Caldara et al (2005), Schyns et al (2002). Small idiosyncrasies were observed between these two typical groups, for example, adults consistently also used a left side jawline cue.…”

Deficits in face perception in the amnestic form of mild cognitive impairment

“…Rather, a selective problem with processing the eye region at unlimited durations is reminiscent of the deficit in some studies of acquired prosopagnosia patients, many with fusiform lesions [29,[38][39][40][41][42]. These show reduced diagnosticity of the eye region of the face [38,39] and fewer ocular fixations on the upper face [40].…”

“…This may reflect several factors. The ocular region has a wealth of structural detail [42] with considerable local configural as well as long-distance metric relations to other facial features [48], more so than for features such as the mouth and nose [49,50]. Details from the upper part of the face may offer particularly salient information in the initial structuring of categorical knowledge about individual faces [51] and may have particular importance in social signaling, as with direction of gaze [52].…”

Early sensitivity for eyes within faces: A new neuronal account of holistic and featural processing

“…The eyes seem to be the diagnostic feature used to recognize identity, several facial expressions, and gender (Dupuis-Roy et al, 2009;Schyns et al, 2007). Better expertise in face processing seems to be driven by better information extraction from the eye region (Vinette et al, 2004), a capacity that might go awry in some cases of prosopagnosia in which the eye region is not properly attended (Caldara et al, 2005). Eyes provide essential cues to others' attention and intention through gaze perception, putting them at the core of social cognition and its impairments as seen in Autism Spectrum Disorder (Itier & Batty, 2009 for a review).…”