Prosopagnosia: Seeing the World through Fog-Colored Glasses :: Biology Essays Research Papers

Prosopagnosia: Seeing the World through Fog-Colored Glasses With impressive consistency, the visual system, along with each accompanying component that in sum total constitutes a person, develops without error. Patterns of input impinge on complex layers of cells, with the resulting neural interpretation allowing us to negotiate the spatial world around us such that we may avoid causing harm to ourselves or to others. Various devices and techniques have been devised to allow those who are not equipped with a similarly functioning visual system to escape natural selection's discerning grasp. However, various gradations of dysfunction exist between perfect and no vision, which complicate the life of the person suffering from these disorders no less. The disorder prosopagnosia, in particular, otherwise known as "face blindness," causes a crippling deficit in a person's ability to recognize faces (1, 2, 3, 6, 7). It is a somewhat ill understood and deceiving phenomenon. Those individuals suffering from prosopagnosia are able to see perfectly well , to the extent that their perception of visual stimuli is not impaired. However, when presented with a person's face, they are utterly unable to recall having seen that face or having interacted with the person attached to it. Some people would make the distinction between prosopagnosia and facial agnosia (4, 8), with the former applying only to familiar faces while the latter applies more generally to prevent the recognition of any faces. While this might suggest memory impairment as a possible cause, evidence for perceptual deficits has been consistent (4), thereby refuting the notion that these individuals are simply not able to remember people they have encountered. Specifically, the locus of damage that results in prosopagnosia appears to be the medial occipitotemporal cortex (4), though the disorder may be congenital or acquired (2). Lesions in this somewhat posterior and deeply embedded region of the brain, suggested by some researchers to be bilateral in the instance of this disorder, would be consistent with the presented deficits in perception. However there are certain elements of the research and the disorder which seem counterintuitive. For instance, that these "face blind" individuals only ci te difficulty in recognizing familiar faces suggests that the problem may be more than just perceptual. Furthermore, there is separate evidence suggesting that visual processing occurs on a unilateral level (4), and that stimuli are perceived contralaterally. This orientation does not preclude a bilateral lesioning being at the root of prosopagnosia, however it does offer some complicating factors.