Affiliations: Faculty of Psychology, University of Lisbon, Lisbon, Portugal
Note: [] Corresponding author: Faculdade de Psicologia, Universidade de
Lisboa, Alameda da Universidade, 1649-013 Lisboa, Portugal. Tel.: +351
217943655; Fax: +351 217933408; E-mail: [email protected]
Abstract: Data from neuropsychological research suggest that categorizing
objects at different levels of specificity requires different cognitive and
neural processes. This short paper presents and discusses a theoretical
hypothesis for this organization in terms of feature sharedness. It is proposed
that superordinate concepts involve a larger absolute number of exemplars that
share a particular feature, thus making them more resistant to damage than
basic level concepts (i.e. superordinate advantage). Simultaneously, in
relative terms, features are less shared overall by superordinate members than
by basic level members, which imply higher executive requirements and can
conversely lead to superordinate deficits. This hypothesis is discussed in
relation to behavioral data from semantic dementia and stroke aphasia patients
and fMRI data from healthy subjects that support the role of feature sharedness
in the hierarchical organization of semantic knowledge.
