ACT-R Adaptive Control of Thought – Rational
An Integrated Theory of the Mind
By Nina Department of Psychology, Zhejiang Sci-Tech University Contact me : [email protected]
What
Where How
ACT-R
Cognitive Psychology
Brain Imaging
What ?
Cognitive Computing
fMRI Lisp
John Anderson
Models
Declarative
Procedural
Symbolic
Java Python
Memory
Attention Complex Tasks
Executive Control
Education
Neuroscience Language
Decision HCI
ACT-R is a cognitive architecture: a theory for simulating and understanding human cognition. Researchers working on ACT-R strive to understand how people organize knowledge and produce intelligent behavior. As the research continues, ACT-R evolves ever closer into a system which can perform the full range of human cognitive tasks: capturing in great detail the way we perceive, think about, and act on the world.
What ?
History
Inspiration
1973-1990
1990-1998
1998-present
What ?
History
Inspiration
1973-1990
1990-1998
1998-present
Allen Newell
The idea of unified theories
An ultimate scientific questions: How can the human mind occur in the physical universe ? A presentation on 4 December 1991.
What ?
History
Inspiration
1973-1990
1990-1998
1998-present
Allen Newell
John R. Anderson Gordon Bower
Early years: HAM and ACT theory 1
The idea of unified theories
Human Associative Memory --the original declarative memory system --described by Anderson & Bower in 1973
The 1st version of the ACT theory --introducing a computational dichotomy
+ the procedural memory
The ACT* model of human cognition
What ?
History
Inspiration
1973-1990
1990-1998
1998-present
Allen Newell
John R. Anderson Gordon Bower
Early years: HAM and ACT theory 1
The idea of unified theories Integration with rational analysis
John R. Anderson
Rational Analysis, a mathematical approach to cognition, whose basic assumption of Rational Analysis is that cognition is optimally adaptive, and precise estimates of cognitive functions mirror statistical properties of the environment.
Rational Analysis (as a unifying framework)
the ACT theory
ACT-R
+ The importance of the new approach in the shaping of the architecture
ACT-R 4.0 --optional perceptual and motor capabilities --mostly inspired from the EPIC
What ?
History
Inspiration
1973-1990
1990-1998
1998-present
Allen Newell
John R. Anderson Gordon Bower
Early years: HAM and ACT theory 1
The idea of unified theories Integration with rational analysis
John R. Anderson
CMU Groups
Current developments
ACT-R 4.0 --optional perceptual and motor capabilities --mostly inspired from the EPIC
ACT-R 5.0 --introducing the concept of modules --specialized sets of procedural and declarative representations that could be mapped to known brain systems --Specialized structures for holding temporarily active information
ACT-R 6.0 --a new version of the code, presented in 2005 --including significant improvements in the ACT-R coding language
a cognitive architecture
a programming language
What ?
Basic Theory
What ?
Basic Theory
• time to perform the task, • accuracy in the task, and, • (more recently) neurological data such as those
obtained from FMRI. • collect quantitative measures that can be directly
compared with the quantitative measures obtained from human participants.
Where ?
Models
learning and memory
problem solving & decision making
language & communication
cognitive development individual differences
perception & attention
Where ?
Applications
Some of the most successful applications, the Cognitive Tutors for Mathematics, are used in thousands of schools across the country. Such "Cognitive Tutors" are being used as a platform for research on learning and cognitive modeling as part of the Pittsburgh Science of Learning Center.
How ?
Mechanism
Modules
Buffers
Pattern matcher
Main components
How ?
Modules
Take care of with the real word The visual and the manual models
Two kinds of memory modules
Perceptual-motor modules
Memory modules
How ?
Memory Modules
Declarative memory
Procedural memory
How ?
Memory Modules
Declarative memory: facts
Procedural memory
Eg. Washington D.C. is the capital of United States.
How ?
Memory Modules
Declarative memory: facts
Procedural memory: productions
Eg. How to type the word “COPSY”.
How ?
Buffers
• ACT-R accesses its modules (except for the procedural-memory module) through buffers.
• For each module, a dedicated buffer serves as the interface with that module.
• The contents of the buffers at a given moment in time represents the state of ACT-R at that moment.
How ?
Pattern matcher
• The pattern matcher searches for a production that matches the current state of the buffers.
• Only one such production can be executed at a given moment.
• That production, when executed, can modify the buffers and thus change the state of the system.
• Thus, in ACT-R cognition unfolds as a succession of production firings.
How ?
Pattern matcher
ACT-R is a hybrid cognitive architecture.
Its symbolic structure is a production system.
The subsymbolic structure is represented by a set of massively parallel processes that can be summarized by a number of mathematical equations.
The subsymbolic equations control many of the symbolic processes,whether (or how fast) a fact can be retrieved from declarative memory depends on subsymbolic retrieval equations, which take into account the context and the history of usage of that fact.
They are also responsible for most learning processes in ACT-R.
How ?
Detailed Information
"How Can the Human Mind Occur in the Physical Universe" (2007)
Any question? Thank you.
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