Trends in Cognitive Sciences
The organization of conceptual knowledge: the evidence from category-specific semantic deficits
Section snippets
The Sensory/Functional theory
The original formulation of the Sensory/Functional theory by Warrington and collaborators 1, 2, 3 made two basic assumptions: (1) the semantic system is organized into modality-specific semantic subsystems (e.g. visual/perceptual, functional/associative); and (2) the ability to recognize/name living things differentially depends on visual/perceptual information, whereas the ability to recognize/name non-living things differentially depends on functional/associative information (for related
The Organized-Unitary-Content hypothesis
Although early discussions of the organization of the conceptual system focused on the assumption that conceptual knowledge is organized into modality-specific subsystems [32], some authors argued against this hypothesis and in favor of a unitary, amodal system of conceptual organization 33, 34, 35. The Organized-Unitary-Content hypothesis (OUCH) [34] is one such proposal. OUCH makes two basic assumptions: (1) conceptual features corresponding to object properties that often co-occur will be
Interim summary and directions
The three proposals reviewed above (the Sensory/Functional theory, the Domain-Specific hypothesis, and the Conceptual-Structure account) are contrary hypotheses of the causes of category-specific semantic deficits. However, the individual assumptions that comprise each account are not necessarily mutually contrary. For instance, whereas the Sensory/Functional theory can be rejected as a viable hypothesis of the causes of category-specific semantic deficits, it remains an open question as to
Clues from functional neuroimaging
In this section we address two questions: (1) Is there evidence from functional neuroimaging that different areas of the brain are differentially involved in processing/storing information corresponding to different categories of objects? (2) If so, do such data motivate the assumption that one constraint on the physical distribution of conceptual information in the brain is type or modality of information? We note at the outset that the scope of the empirical review to follow is limited to an
Conclusion
We have evaluated three hypotheses of the causes of category-specific semantic deficits. The basic predictions made by the Sensory/Functional theory 1, 2, 3, which was until recently the received view, are at variance with the facts of category-specific semantic deficits. The OUCH model [33] is not inconsistent with the facts of category-specific deficits but is too underdeveloped to provide a useful framework for interpreting those facts. When OUCH-type models have been elaborated to the point
Acknowledgements
The preparation of this article was supported in part by NIH grant DC 04542 to Alfonso Caramazza. We thank Erminio Capitani, Argye Hillis, Marcella Laiacona, and Jenni Shelton Young for sharing with us their ideas on the nature of category-specific semantic deficits, and Alex Martin and Lauren Moo for helping us to understand the neuroimaging data on conceptual knowledge. We also thank Joe Devlin and the anonymous reviewers for helpful comments on an earlier version of this paper.
References (65)
- et al.
Semantically bounded anomia: implication for the neural implementation of naming
Neuropsychologia
(1992) Category-specificity and modality-specificity in semantic memory
Neuropsychologia
(1989)Perceptual and associative knowledge in category specific impairment of semantic memory: a study of two cases
Cortex
(1993)- et al.
A progressive category-specific semantic deficit for non-living things
Neuropsychologia
(2000) - et al.
Towards a distributed account of conceptual knowledge
Trends Cogn. Sci.
(2001) Conceptual structure and the structure of concepts: a distributed account of category-specific deficits
Brain Lang.
(2000)Double dissociation of semantic categories in Alzheimer's disease
Brain Lang.
(1997)Category-specific impairment in patients with Alzheimer's disease as a function of disease severity: a cross-sectional investigation
Neuropsychologia
(2002)The effect of face inversion on activity in human neural systems for face and object perception
Neuron
(1999)Parallel visual motion processing streams for manipulable objects and human movements
Neuron
(2002)