A social signal that helps judge personality or mating potential 

 

Vancouver, BC, CA. Beauty may be in the eye of the beholder, but according to research conducted by a third-year medical student, eye candy fails to find a sweet tooth in patients with a rare disorder.

Chris Waite, University of British Columbia (UBC), has studied how patients with prosopagnosia — the inability to recognize familiar faces, even family members, because of brain injury — perceive facial attractiveness.

 

The findings may provide another assessment tool to help clinicians localize areas of brain damage.

 

“We don’t know a tenth of what goes on the brain,” says the 26-year-old. “Face perception is a highly complex visual skill. Exploring how the brain processes judgments about facial beauty help us identify the role of various regions of the brain.”

 

Waite worked with UBC prof Jason Barton, Canada Research Chair in the Neuropsychology of Vision and Eye Movements, and investigators from Harvard and the Massachusetts Institute of Technology. The study was the first of its kind and earned Waite the American Academy of Neurology Award for best medical student essay. 

 

The research team studied eight individuals with prosopagnosia, an impairment also known as of face-blindness. They wanted to know where the brain processes visual information that adds up to a judgment about facial attractiveness.

 

Researchers are studying brain damage that causes "face blindness" which in severe cases means individuals can't recognize their own reflection.

 

Photo: Martin Dee.

 

 

Individuals with prosopagnosia have trouble extracting and integrating information they see in a face and rely on other characteristics, such as hair, body shape and gait to recognize people. The condition can result from trauma to the head, illness such as encephalitis, or inflammation of the brain, stroke, coma or insufficient oxygen supply at birth. In 2006, a web survey of 1,600 people conducted jointly by a team from Harvard and University College London suggested that up to two per cent of people have some degree of face-blindness.

 

The damaged area of the brain for those with face-blindness is usually found in the medial side of the occipital (low back of the brain, near the spinal cord) and temporal, or side lobes. The region is called the fusiform face area. Because attractiveness depends on non-changing elements of facial structure — which in Western society include a strong jaw, big eyes and a straight nose — it was thought that attractiveness might be processed in this area.

 

However, because attractiveness is a social signal that helps us judge personality or mating potential, scientists believed it might be processed in a region of the brain that “reads” changing facial properties, an area called the superior temporal sulcus that is located at the tops of the temporal lobes. Although prosopagnosia patients cannot identify faces, they can judge subtle facial clues, such as a raised eyebrow or pursed lips that express emotion and convey social cues.

 

The investigators’ wanted to determine if recognizing facial beauty took place in the region that supports identification (fusiform face) or the one supporting social signals (superior temporal sulcus). 

 

The research subjects, heterosexual men and women prosopagnosics ranging in age from 20s to 60s, were shown 80 anonymous male and female faces, both average and attractive, and asked to rate their attractiveness. A second test involved viewing a series of similar images while researchers timed how long participants looked at each image. A control group of 19 provided comparison data. Prosopagnosics also looked at famous beautiful faces to further test the relationship between ability to identify familiar faces and ability to judge beauty.

 

Both tasks showed that the same damage that prevented them from identifying faces impaired prosopagnosics in processing facial attractiveness. They rated the attractiveness of beautiful faces only slightly higher than average faces.  Also, they were much more willing than the control group to continue looking at images of average faces.

 

The researchers concluded that processing facial attractiveness must use the same neural pathways superior temporal sulcus — those found in the fusiform region of the brain — used to process identity.

 

“While the beauty of a face might seem a more fitting topic for an artist, this work helps settle a debate by showing that areas that code the identity of a face also play a key role in the perception of beauty,” says Jason Barton. "It helps us understand the contributions of different ‘modules’ of the brain to human experience." Barton is an investigator at the Brain Research Centre at UBC Hospital and a member of the Vancouver Coastal Health Research Institute (VCHRI).

 

Although Waite feels fortunate to have conducted research with eminent neuroscientists, his heart still belongs to medicine and vision science in particular, influenced in part by his mother who is an optician. Once he completes his undergraduate degree in medicine, Waite is considering a residency in ophthalmology, among other options.

“I think vision is the most important sense,” he says. “If I could fix something to make a patient’s life better, that would be a great feeling. That’s what I want to do.”

 

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Funding for the study was provided by the American Academy of Neurology and the UBC Dept. of Ophthalmology and Vision Sciences Thomas Dohm Scholarship.

 

Abstract. Prosopagnosia is a deficit in face recognition in the presence of relatively normal object recognition. Together with older lesion studies, recent brain-imaging results provide evidence for the closely related representations of faces and objects and, more recently, for brain areas sensitive to faces and bodies. This evidence raises the issue of whether developmental prosopagnosics may also have an impairment in encoding bodies. We investigated the first stages of face, body, and object perception in four developmental prosopagnosics by comparing event-related potentials to canonically and upside-down presented stimuli. Normal configural encoding was absent in three of four developmental prosopagnosics for faces at the P1 and for both faces and bodies at the N170 component. Our results demonstrate that prosopagnosics do not have this normal processing routine readily available for faces or bodies. A profound face recognition deficit characteristic of developmental prosopagnosia may not necessarily originate in a category-specific face recognition deficit in the initial stages of development. It may also have its roots in anomalous processing of the configuration, a visual routine that is important for other stimuli besides faces. Faces and bodies trigger configuration-based visual strategies that are crucial in initial stages of stimulus encoding but also serve to bootstrap the acquisition of more feature-based visual skills that progressively build up in the course of development.

 

 

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