Task 5- M&M Flashcards
What does ACT-R stand for?
Adaptive character of thought theory: complex cognition arises from an interaction of procedural and declarative knowledge
How is procedural knowledge represented?
procedural knowledge = skills; in units called production rules
How is declarative knowledge represented?
in units called chunks
How are individual units created?
by simple encodings of objects in the environment (chunks) or simple encodings of transformations in the environment (production rules)
What does the power of human cognition depend on according to the ACT-R theory?
depends on the amount of knowledge encoded and the effective deployment of the encoded knowledge
How is intelligence seen according to ACT-R theory? (in reference to Gestalt principle)
- simply the accrual and tuning of many small units of knowledge that in total produce complex cognition
- > The whole is no more than the sum of its parts, but it has a lot of parts
What are production rules?
- embody procedural knowledge
- conditions and actions are defined in terms of declarative structures
What can production rules create?
new declarative structures
How are production rules represented?
-in terms of chunks -> schema-like structures (consist of an isa-pointer specifying their category and some number of additional pointers encoding their contents
How can chunks be created/ where do they originate from?
- can be created by actions of production rules
- chunks originate from encoding of environment -> ACT-R sensationalist theory
How do chunks originate from encoding of the environment?
- Seeing object -> system associates a set of features with each object
- Features within spotlight ->synthesized into recognized objects ->objects are then available as chunks in ACT’S working memory
How are shifts of attention controlled in the ACT-R model?
by explicit firings of production rules
What about features of an object before an object is recognized in the ACT-R model?
features (e.g. the bars in the letter H) are available as parts of an object, but object itself is not recognized
Can the ACT-R system respond to features anywhere in the visual field?
-When can it recognize a pattern?
can respond to feature anywhere in the visual field BUT can only recognize a pattern (=conjunction of parts) if it pays attention to it
How is knowledge made available in a particular context in the ACT-R model? What is the formula?
made available according to the odds of being used in a particular context
–>Posterior odds= Prior-odds* likelihood- ratio
What do ACT-R, which memory to choose and which category to place an object in all have in common?
all are sensitive to both prior information and information about appropriateness to the situation at hand
What is the goal of cognitive modeling?
to scientifically explain one or more of these basic cognitive processes, or explain how these processes interact e.g. perceiving, learning, remembering
What are two hallmarks of cognitive modeling?
- are described in formal mathematical or computer language
- are derived from basic principles of cognition
What are 3 advantages of cognitive modeling?
- by using mathematical or computer languages, cognitive models are guaranteed to produce logically valid predictions
- capable of making precise quantitative predictions
- generalizability
What are examples of cognitive models?
- prototype model of categorization
- exemplar model of categorization
- artificial neural network models
- decision tree models
- production rule models of categorization
What are the 5 steps of coming up with a cognitive model?
1. Reformulate a conceptual theoretical framework into a more computational, mathematical one
2. Adhoc assumptions: add smth if theory is too weak
3. Estimate the parameters (weight that are initially unknown) -> based on observations
4. Compare your model with other models and decide which is the better one
5. Reformulate theoretical framework and start constructing new models based on feedback and results
Which different theories of cognitive modeling are there?
- Logic Theorist by Newell, Shaw and Simon
- GPS (General Problem Solver) by Newell and Simon -> rule-based; Logic Theorist generalized into GPS; (used rules to simulate human solutions to various kinds of problems)
- ACT system by Anderson-> rule-based
- ACT-R by Anderson
Which features of production rules are there?
- IF part= condition
- THEN part= action
- represent general information about the world or represent information about how to do things in the world (declarative and procedural knowledge)
- can have multiple conditions and actions
How do the ACT-R and the recognition heuristic relate to each other?
- Chunk/ production rules as heuristics in ACT-R
- Chunks: like prototype; use of prototypes which integrate features and recognize object -> Recognition heuristic: recognize stuff by prototype
- If…then rule
- The more often its used, the more easily it is retrieved
