This groundbreaking monograph offers a mechanistic theory of the
representation and use of semantic knowledge, integrating the strengths and
overcoming many of the weaknesses of hierarchical, categorization-based
approaches, similarity-based approaches, and the approach often called
"theory theory." Building on earlier models by Geoff Hinton in the 1980s
and David Rumelhart in the early 1990s, the authors propose that
performance in semantic tasks arises through the propagation of graded
signals in a system of interconnected processing units. The representations
used in performing these tasks are patterns of activation across units,
governed by weighted connections among them. Semantic knowledge is acquired
through the gradual adjustment of the strengths of these connections in the
course of day-to-day experience.
The authors show how a simple computational model proposed by Rumelhart
exhibits a progressive differentiation of conceptual knowledge, paralleling
aspects of cognitive development seen in the work of Frank Keil and Jean
Mandler. The authors extend the model to address aspects of conceptual
knowledge acquisition in infancy, disintegration of conceptual knowledge in
dementia, "basic-level" effects and their interaction with expertise, and
many findings introduced to support the idea that semantic cognition is
guided by naive, domain-specific theories.
Timothy T. Rogers is a research scientist at the Medical Research Council
Cognition and Brain Sciences Unit in Cambridge, England. James L.
McClelland is Bingham Professor of Psychology and Cognitive Neuroscience at
Carnegie Mellon University and Codirector of the Center for the Neural
Basis of Cognition at Carnegie Mellon and the University of Pittsburgh. He
is the author, with David E. Rumelhart and the PDP Research Group, of
Parallel Distributed Processing: Explorations in the Microstructure of
Cognition (MIT Press, 1986).