Abstract
Variability of the representation
Abstract
Objects contours a b s t r a c t
Abstract
We evaluated the contribution of four structural dimensions (object parts, internal details, objects contours and variability of the representation), as a possible source of categorical processing differences and category-specific deficits. Importantly, these dimensions aggregate 22 different structural measures that have been proposed to describe the Snodgrass and Vanderwart (1980) picture set. Study 1 analysed the differences between the four dimensions across domains and categories. Study 2 investigated how these dimensions may contribute to the performance of two patients with category-specific deficits that have been reported previously in the literature (Farah et al., 1991). The results showed that living things were structurally more complex than non-living things, scoring higher in object parts and object contours. Regarding the variability of the representation, living things did not show much within-item diversity but did show more contour overlap and less visual similarity, the latter two qualities of living things being detrimental to object processing in a naming task. Parts, contours and variability of the representation also differentiated animals, fruits and vegetables and, to a certain degree, non-living things: animals had more parts, fruits had more object contours and non-living things had a lower variability of the representation (which was especially related to higher within-item diversity and lower contour overlap). The same three dimensions predicted patient performance. However, when structural dimensions were considered together with domain (living/non-living) and concept familiarity, only variability of the representation contributed significantly to patient performance.
Abstract
ª 2011 Elsevier Ltd. All rights reserved.
Abstract
The study of brain-damaged patients exhibiting impaired knowledge for one or several categories of objects and relatively preserved knowledge for other categories has been crucial for the current understanding of conceptual organization. The first clinical observations of these category-specific deficits were reported by Nielsen in 1946 (Forde and Humphreys, 1999), and Warrington and Shallice (1984) provided the first systematic empirical study of these patients. Since then a considerable number of other cases have been described (e.g., Capitani et al., 2003; Forde and Humphreys, 1999). The notion that structural factors (and visual complexity in particular) may play an important role in the observation of category-specific deficits has been extensively discussed (e.g., Cree and McRae, 2003; Funnell and Sheridan, 1992; Mahon and Caramazza, 2009 Available herrerajohn@example.org
Abstract
Journal homepage: www.elsevier.com/locate/cortex c o r t e x 4 9 ( 2 0 1 3 ) 2 6 6 e2 7 5
Abstract
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a b s t r a c t
We evaluated the contribution of four structural dimensions (object parts, internal details, objects contours and variability of the representation), as a possible source of categorical processing differences and category-specific deficits. Importantly, these dimensions aggregate 22 different structural measures that have been proposed to describe the Snodgrass and Vanderwart (1980) picture set. Study 1 analysed the differences between the four dimensions across domains and categories. Study 2 investigated how these dimensions may contribute to the performance of two patients with category-specific deficits that have been reported previously in the literature (Farah et al., 1991) . The results showed that living things were structurally more complex than non-living things, scoring higher in object parts and object contours. Regarding the variability of the representation, living things did not show much within-item diversity but did show more contour overlap and less visual similarity, the latter two qualities of living things being detrimental to object processing in a naming task. Parts, contours and variability of the representation also differentiated animals, fruits and vegetables and, to a certain degree, non-living things: animals had more parts, fruits had more object contours and non-living things had a lower variability of the representation (which was especially related to higher within-item diversity and lower contour overlap). The same three dimensions predicted patient performance. However, when structural dimensions were considered together with domain (living/non-living) and concept familiarity, only variability of the representation contributed significantly to patient performance.
a b s t r a c t
ª 2011 Elsevier Ltd. All rights reserved.
Introduction
The study of brain-damaged patients exhibiting impaired knowledge for one or several categories of objects and relatively preserved knowledge for other categories has been crucial for the current understanding of conceptual organization. The first clinical observations of these category-specific deficits were reported by Nielsen in 1946 (Forde and Humphreys, 1999 ), and Warrington and Shallice (1984 provided the first systematic empirical study of these patients. Since then a considerable number of other cases have been described (e.g., Capitani et al., 2003; Forde and Humphreys, 1999) . The notion that structural factors (and visual complexity in particular) may play an important role in the observation of category-specific deficits has been extensively discussed (e.g., Cree and McRae, 2003; Funnell and Sheridan, 1992; Mahon and Caramazza, 2009 ). Several authors have proposed that these category-specific deficits may be at least partially explained by differences

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