Abstract
ABSTRACTMultiple accounts have been proposed to explain category-specific recognition impairments. Some suggest that category-specific deficits may be caused by a deficit in recurrent processing between the levels of a hierarchically organized visual object recognition system. Here, we tested predictions of interactive processing theories on the emergence of category-selective naming deficits in neurologically intact observers and in patient GA, a single case showing a category-specific impairment for natural objects after a herpes simplex encephalitis infection. Fragmented object outlines were repeatedly presented until correct naming occurred (maximum 10 times), and the fragments increased in length with every repetition. We studied how shape complexity, object category, and fragment curvature influence the timing of correct object identification. The results of a survival analysis are consistent with the idea that deficits in recurrent processing between low- and high-level visual object representations can cause category-selective impairments.
Highlights
Multiple accounts have been proposed to explain category-specific recognition impairments
The category body-parts was typically spared in the former patients but impaired in the latter, while the category food was typically spared in the latter patients but impaired in the former (Gainotti, 2000). These results show that the pattern of categorical impairment does not respect the natural/living versus manmade/nonliving distinction, and strongly suggest that the injured brain areas house exactly those neurophysiological mechanisms that contribute to the acquisition of the disrupted semantic categories: the acquisition account (Gainotti et al, 1995)
We used a build-up paradigm where we repeatedly presented a fragmented object outline during a trial, until the observer could correctly name the object depicted at the basic level
Summary
Multiple accounts have been proposed to explain category-specific recognition impairments. We tested predictions of interactive processing theories on the emergence of category-selective naming deficits in neurologically intact observers and in patient GA, a single case showing a category-specific impairment for natural objects after a herpes simplex encephalitis infection. The sensory/functional account was proposed by Warrington and Shallice (1984) They investigated the visual identification deficits of four patients who made a partial recovery from a herpes simplex encephalitis (HSE) infection. Categories arise because semantic knowledge is organized in a domain-specific manner, distinguishing natural and manmade stimuli They argued that “evolutionary pressures have resulted in specialized mechanisms for perceptually and conceptually distinguishing animate and inanimate kinds leading to a categorical organization of this knowledge in the brain” They argued that “evolutionary pressures have resulted in specialized mechanisms for perceptually and conceptually distinguishing animate and inanimate kinds leading to a categorical organization of this knowledge in the brain” (p. 17)
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