ACT-R Adaptive Control of Thought – Rational

An Integrated Theory of the Mind

By Nina Department of Psychology, Zhejiang Sci-Tech University Contact me : weizhuxiaona@gmail.com

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.