The Newell Test for a Theory of Mind Anderson, John R., & Lebiere, Christian (forthcoming), “The Newell Test for a Theory of Mind”, Behavioral & Brain Sciences Newell, Allen (1980), “Physical Symbol Systems”, Cognitive Science 4: Newell, Allen (1990), Unified Theories of Cognition (Cambridge, MA: Harvard University Press).

The Newell Test Based on lists of criteria that cognitive theories should satisfy. Anderson & Lebiere: –Classical connectionism: Newell-test strengths: –Addresses empirical phenomena –Especially in language, cognitive development NT weaknesses: –Fails to acknowledge symbolic level of thought –ACT-R (Anderson’s own theory): NT strengths: –Includes symbolic & subsymbolic components –Both are tightly integrated NT weaknesses: –Lacks intensive analyses of some NT criteria

Newell’s Criteria: Summary 12 functional constraints on cognitive architecture –First 9: Things needed “to implement human intellectual capacity” –Last 3: “Constraints on how these functions are to be achieved” There are others, not on the list: –E.g., a system could satisfy all 12, but “not correspond to the human mind” –So: could add others (but won’t): Behavioral adequacy: –cognitive theory should correspond to details of human cognition Be capable of practical application (e.g., to education, therapy) There is a grading scheme!

Newell’s 12 Criteria 1.Flexible behavior 2.Real-time performance 3.Adaptive behavior 4.Vast KBnecessary 5.Dynamic behavior for 6.Knowledge integrationcognition 7.Natural language 8.Consciousness 9.Learning 10.Development 11.Evolutionconstraints 12.Brain

1. Flexible Behavior I.e., computational universality Grading: –If theory is well-specified, then s/b easy to determine whether computationally universal –Doesn’t require that: people find everything equally easy human performance be error free

2. Real-Time Performance Theory should explain how humans can satisfy criterion 1 in real time Grading: –If theory has well-specified constraints on speed of its processes, then s/b easy to determine whether it can achieve real time for specific cases of cognition

3. Adaptive Behavior Human computations are relevant to their needs –How do basic processes of the architecture serve useful functions? –How is the whole system put together? Does its overall computation meet human needs? Grading: –If theory is completely specified, then s/b able to determine if its behavior would be functional in real world

4. Vast Knowledge Base Distinguishes human cognition from expert systems –Problems: Not all K is equally reliable or relevant Relevance can change with time Storage/retrieval problems Grading: –Determine how performance changes with scale of KB –If theory is well specified, then s/b able to formally analyze –Size may affect performance Cf. learning names of 20 students vs. 200 students

5. Dynamic Behavior Precondition for survival: –World can change in unexpected & uncontrollable ways –Human actions can have unexpected effects –Requires theories of perception, action, & cognition BUT: NOT(reaction is all there is to cognition) But also: NOT(cognition can ignore external world) Grading: –Test system in an uncontrolled environment

6. Knowledge Integration I.e., achieving the capability to “combine symbols intellectually” in order to make inferences about the external world Grading: –Can the theory deal with inference, induction, metaphor, analogy

7. Natural Language Complete theory of mind must be able to communicate in NL –Newell: language depends on symbol manipulation (! ) Grading: –Read a passage & answer questions about it. Requires parsing, comprehension, inference, use of prior knowledge Conversational ability is nice, but not necessary

8. Consciousness Important for a full theory of human cognition –[what about a full theory of cognition, simpliciter?] Grading: –Ability to produce subliminal perception, implicit learning & memory, metacognitive processes –& show how they are functional aspects of human cognition

9. Learning “Theory of cognition must account for humans’ ability to acquire their competencies” Grading: –Semantic memory, episodic memory, skills, priming, conditioning Based on Squire’s (1992) theory of memory in the hippocampus

10.Development (constraint #1) Human cognition is constrained to unfold as the organism grows & responds to experience. Grading: –Can the theory account for specific cases of developmental progression?

11. Evolution (constraint #2) Evolutionary constraint: –Human cognitive abilities evolved Comparative constraint: –Differences between human and other-mammalian cognition E.g., cognitive plasticity, language What’s unique to human cognition? Grading: –How does the theory relate to these constraints?

12. Brain (constraint #3) Degree to which data about brain functioning constrains the cognitive theory. Grading: –Enumeration: Mapping of parts of the cognitive architecture onto brain structures –Proof: Brain computations match cog-arch computations

Grading BEST: criterion on which theory has done the best Better:4 criteria on which the theory has done better mixed:2 criteria on which theory has most mixed record worse: 4 criteria on which the theory has done worse worst: criterion on which theory has done the worst

Scoreboard CriterionConn’ismACT-RSNePS Flexible mixedBetter Mixed Real-time worse BEST Mixed Adaptive Better Worse Vast KB worse mixed Better Dynamic mixedBetter Worse Kn. Integration worse mixed Best Nat. Lang. Better worse Better Conscious worse Better Learning Better Development Better worse Worse Evolution worst Worst Brain BEST worse

Comparative Ranking GradeConnec’ismACT-RSNePS BESTBRAINREAL-TIME KN. INTEG BetterLearning Nat’l Lang Adaptive Conscious. DevelopmentDynamic Vast KB Nat’l. Lang.Flexible Learning mixedflexiblek. integration Flexible dynamicvast k.b. Real Time worsereal-timenat’l. lang. Dynamic vast k.b.development Adaptive k. integrationbrain Developmt consciousness Brain worstevolution