1. Title of tutorial: Introduction to the ACT-R cognitive architecture

2. Name of contact person: John R. Anderson

3. Affiliation: Psychology Department
                Carnegie Mellon University

4. Address including post code/zip code and country:
                Pittsburgh, PA 15213
                USA

5. Telephone: +1 (412) 268-2788

   Fax:       +1 (412) 268-2844

   Email:     ja+@cmu.edu

6. Names and affiliations of additional authors:

   Christian Lebiere
   Psychology Department
   Carnegie Mellon University
   Pittsburgh, PA 15213
   USA
   Tel: +1 (412) 268-2815
   Fax: +1 (412) 268-2844
   Email: cl+@cmu.edu    

7. Duration of your proposed tutorial: Full day (6 hours)

8. Resource needs: Overhead projector and display panel.

9. Abstract (not to exceed 200 words), for inclusion in conference
   announcements and the program:

This tutorial will cover the fundamentals of the ACT-R architecture. 
ACT-R is a cognitive architecture based on experimental results and
theoretical assumptions about the acquisition, organization and
application of human knowledge.  It is a fully implemented simulation
system that has been applied to tasks ranging from simple reaction time
to complex air traffic control.  The goal of this full-day tutorial is
to provide a comprehensive introduction to the ACT-R theory, including
knowledge representation, symbolic and subsymbolic levels, and learning
mechanisms.  Numerous examples will be presented interactively to
illustrate each theoretical concept.  While the length of this tutorial
will not allow participants to complete any exercises, the aim is to
provide a sufficiently detailed introduction to the architecture as to
allow them to complete on their own the exercises provided as part of
the interactive web tutorial available on the ACT-R home page
(http://act.psy.cmu.edu).

10. Abstract biography of presenter(s), (not to exceed 200 words total):

John R. Anderson is the Walter VanDyke Bingham Professor of psychology
and computer science at Carnegie Mellon University.  He received his
B.A. from the University of British Columbia in 1968 and his Ph.D. from
Stanford University in 1972.  He has developed the ACT theory of human
cognition and  published a number of books including Human Associative
Memory (1973 with Gordon Bower), Language, Memory, and Thought (1976),
The Architecture of Cognition (1983), The Adaptive Character of Thought
(1990), Rules of the Mind (1993) and The Atomic Components of Thought
(1998 with Christian Lebiere).

Christian Lebiere is a post-doctoral researcher in the psychology
department at Carnegie Mellon University.  He received his B.S. in
computer science in 1986 from Universite de Liege (Belgium) and his M.S.
and Ph.D. in computer science in 1990 and 1998 respectively from
Carnegie Mellon University.  His interests include cognitive science,
machine learning and hybrid architectures.

11. Case for support - Not more than 1500 words arguing the case
    for including this tutorial at Cognitive Science 1999.
  
This tutorial will cover the fundamentals of the ACT-R architecture. 
ACT-R is a cognitive architecture based on experimental results and
theoretical assumptions about the acquisition, organization and
application of human knowledge.  It is a fully implemented simulation
system that has been applied to tasks ranging from simple reaction time
to complex air traffic control.  Computational modeling is becoming an
increasingly important tool to test and develop cognitive theories.  In
the range of its applications and the details of its predictions, ACT-R
is one of the most advanced instances of that practice.

ACT-R distinguishes between a symbolic and a subsymbolic level.  The
symbolic level rests on the idea of a production system that
differentiates between permanent representations of declarative and
procedural knowledge.  Declarative knowledge is represented in the form
of "chunks" while procedural knowledge is encoded in productions. 
Underlying the symbolic level, a subsymbolic level based on the concept
of "Rational Analysis" (Anderson, 1990) allows the architecture to adapt
to the statistical structure of the environment.  The tutorial describes
the most recent version of ACT-R as it was published in the recent book
"The Atomic Components of Thought" by J.R. Anderson & C. Lebiere
(Erlbaum).  A short introduction to ACT-R is provided in "ACT-R: A
simple theory of complex cognition" (Anderson, 1995: American
psychologist, 51 (4), pp. 355-365).

The tutorial will last for a full day, or about 6 hours, and will be
organized around the following sections, each of which will be
illustrated by example ACT-R models.  Each section will be covered in
approximately 1.5 hour, with about an hour for the theoretical
introduction and half an hour for the model demonstrations.

(1) Introduction
This section introduces the basic concepts of ACT-R and provides an
overview of the overall system.  The structure of chunks and productions
is described and the pattern matching process that relates declarative
and procedural knowledge is outlined.  Finally the concept of goals and
their organization in a goal stack are explained.

(2) Performance
This section covers the central subsymbolic concepts of ACT-R and
discusses the processes of activation spreading, partial matching, and
conflict resolution.  Empirical results and example models are presented
to illustrate and justify these concepts.

(3) Learning
ACT-R is a learning architecture which proposes mechanisms to learn new
symbolic knowledge (chunks, productions) as well as their subsymbolic
parameters (chunk and production strength, activation links, cost and
success estimates of productions, etc.).  In this section the various
learning mechanisms are introduced and illustrated by example
applications.

(4) Applications
Finally some ACT-R models and their relationship to empirical data are
presented in detail.  These models, varying from list and sequence
learning to complex problem solving, exemplify the scope of the ACT-R
architecture and emphazise its empirical success.  At the end of the
tutorial we briefly introduce ACT-R/PM, a newly developed
perceptual-motor interface to ACT-R.

Although the attendees are expected to have some familiarity with the
concept of cognitive modelling, no formal pre-requisite is required. 
The tutorial is intended both as an introduction to ACT-R and as a
refresher to participants who might be familiar with a previous version
of the theory (e.g. ACT*).  The tutorial will aim to be as accessible as
possible to anyone with a general interest in cognitive science.

The format will alternate between a theoretical introduction of the
architecture and numerous models illustrating those features.  Those
models will be presented interactively using a display panel.  Even
though participants will not be required to complete any exercises, they
are encouraged to ask questions and make suggestions and the instructors
might demonstrate some modifications to the knowledge structures and
parameters of the models as discussion proceeds.  Ample opportunity will
be provided for discussions and questions throughout the tutorial.

This tutorial was given in a similar format at the European Conference
on Cognitive Model (ECCM98) in April 1998 in Nottingham, England. 
Attendance was excellent, the discussions vigorous, and the participants
generally satisfied.  It has been modified somewhat to include more
recent models as well as portions of the web tutorial used in the ACT-R
summer school for the last five years.  The example material is
available at the ACT-R home page at http://act.psy.cmu.edu.