Technical reports available

[David Chalmers]

The following two technical reports are now available from the Center for
Research on Concepts and Cognition at Indiana University.

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          SYNTACTIC TRANSFORMATIONS ON DISTRIBUTED REPRESENTATIONS

                             David J. Chalmers
          
               Center for Research on Concepts and Cognition
                            Indiana University
                                CRCC-TR-40

There has been much interest in the possibility of connectionist models whose
representations can be endowed with compositional structure, and a variety of
such models have been proposed.  These models typically use distributed
representations which arise from the functional composition of constituent
parts.  Functional composition and decomposition alone, however, yield only
an implementation of classical symbolic theories.  This paper explores the
possibility of moving beyond implementation by exploiting holistic 
structure-sensitive operations on distributed representations.  An experiment
is performed using Pollack's Recursive Auto-Associative Memory.  RAAM is used
to construct distributed representations of syntactically structured sentences.
A feed-forward network is then trained to operate directly on these
representations, modeling syntactic transformations of the represented 
sentences.  Successful training and generalization is obtained, demonstrating
that the implicit structure present in these representations can be used for a
kind of structure-sensitive processing unique to the connectionist domain.

This paper is to appear in CONNECTION SCIENCE.

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                    WHY FODOR AND PYLYSHYN WERE WRONG:
                          THE SIMPLEST REFUTATION

                             David J. Chalmers
          
               Center for Research on Concepts and Cognition
                            Indiana University
                                CRCC-TR-41

This paper offers both a theoretical and an experimental perspective on the
relationship between connectionist and Classical (symbol-processing) models.
Firstly, a serious flaw in Fodor and Pylyshyn's argument against connectionism
is pointed out: if, in fact, a part of their argument is valid, then it
establishes a conclusion quite different from that which they intend, a
conclusion which is demonstrably false.  The source of this flaw is traced to
an underestimation of the differences between localist and distributed
representation.  It has been claimed that distributed representations cannot
support systematic operations, or that if they can, then they will be mere
implementations of traditional ideas.  This paper presents experimental
evidence against this conclusion: distributed representations can be used to
support direct structure-sensitive operations, in a manner quite unlike the
Classical approach.  Finally, it is argued that even if Fodor and Pylyshyn's
argument that connectionist models of compositionality must be mere
implementations were correct, then this would still not be a serious argument
against connectionism as a theory of mind.

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To obtain a copy of either of these papers, send e-mail to
dave at cogsci.indiana.edu.