Technical Report Available

[Melanie Mitchell]

The following technical report is available from the Center for Research on
Concepts and Cognition at Indiana University:

     The Right Concept at the Right Time:  How Concepts Emerge as Relevant 
                  in Response to Context-Dependent Pressures
		            (CRCC Report 42)

                Melanie Mitchell and Douglas R. Hofstadter
              Center for Research on Concepts and Cognition
                            Indiana University

                                  Abstract

     A central question about cognition is how, when faced with a situation, 
     one explores possible ways of understanding and responding to it.  In 
     particular, how do concepts initially considered to be irrelevant, or 
     not even considered at all, become relevant in response to pressures 
     evoked by the understanding process itself?  We describe a model of 
     concepts and high-level perception in which concepts consist of a central
     region surrounded by a dynamic nondeterministic "halo" of potential 
     associations, in which relevance and degree of association change as 
     processing proceeds.  As the representation of a situation is 
     constructed, associations arise and are considered in a probabilistic 
     fashion according to a "parallel terraced scan", in which many routes 
     toward understanding the situation are tested in parallel, each at a rate
     and to a depth reflecting ongoing evaluations of its promise.  We 
     describe Copycat, a computer program that implements this model in the 
     context of analogy-making, and illustrate how the program's ability to 
     flexibly bring in appropriate concepts for a given situation emerges from 
     the mechanisms that we are proposing.

(This paper has been submitted to the 1990 Cognitive Science Society 
conference.)

To request copies of this report, send mail to 

mm at cogsci.indiana.edu or mm at iuvax.cs.indiana.edu

or 

Melanie Mitchell
Center For Research on Concepts and Cognition
Indiana University
510 N. Fess Street
Bloomington, Indiana 47408