An Integrated Theory of the Mind

1. An Integrated Theory of the Mind John Anderson et al.Psychological Review, 111, 1036-1060 (2004)

2. ACT • Computational cognitive model • 20-30 years, army of researchers • Model & modeling environment • Applied to many cognitive tasks • Constrained by common architecture & parameters • Initially focused on high-level cognition • Elaborated with perceptual-motor modules

3. Architecture Long-term Memory Goals Productions Working Memory Perception Action

4. Productions • If-Then rules • Triggered by contents of WM • Depend on current goal, knowledge, and perceptual input • Outputs: • Update goal • Update declarative knowledge • Perform action • “Central decision makers”

5. Example Declarative Knowledge Goal Stack Do Addition Addition Fact Add Units Summand 3 Working Memory Recall Sum Summand 4 Sum 7 Goal: Add Units Summand 3 Sum 7 Summand 4 IF: Goal = Recall Sum Summand X Summand Y Addition Fact: X + Y = Z THEN: Remove Summand X Remove Summand Y Add Sum Z Pop Goal IF: Goal = Add Units Sum X THEN: Write X Pop Goal Goal: Recall Sum Motor Perception 73 +44 “7”

6. Issues • Characterization of modules • Subsymbolic processing • Learning • Modeling complex tasks • Mapping to neuroanatomy