Each dimension explained significant variance in the brain representations (except, surprisingly, “being alive”), however, to a lesser extent than in behaviour. The five dimensions explained much variance in the similarity judgments. We used a stimulus set of 128 images, optimized by a genetic algorithm to disentangle these five dimensions. Here, we investigate the importance of five object dimensions related to animacy (“being alive”, “looking like an animal”, “having agency”, “having mobility”, and “being unpredictable”) in brain (fMRI, EEG) and behaviour (property and similarity judgements) of 19 participants. Despite distinct brain and behavioural responses to animate and inanimate things, it remains unclear which object properties drive these responses. It is proposed that at the behavioural level, category-specific deficits arise when both critical identifying attributes of knowledge are lost and the intercorrelation between features causes disintegration of the category such that each exemplar ‘regresses’ towards a category prototype.ĭistinguishing animate from inanimate things is of great behavioural importance. We suggest that category-specific deficits for living things probably results from a combination of atrophy to medial and neocortical temporal structures, including the inferior temporal lobe. The data are discussed with reference to various theories of category-specific impairment. In fact her comprehension and naming were slightly but significantly better for living things. The other patient with semantic dementia demonstrated relatively poor knowledge of visual attributes but failed to exhibit a category-specific impairment for animate kinds. One patient with dementia of Alzheimer's type presented with relatively poor performance on living things but failed to show a difference between knowledge of visual and associative-functional information. We present data collected from two patients, which question the apparent relationship between category-specific deficits and loss of specific attribute types. Perhaps the most influential view of category-specific deficits is one in which the dissociation between living and non-living kinds reflects differential reliance on, or weighting of visual or associative-functional attributes.
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