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  • each member is unique. lots of perceptual variation, but all treated as identicle category members. CLEAR LINK TO FUNDAMENTALS OF PSYCHOLOGY

Kids, Cats and Concepts: Toward a Grand Unified Theory of ... Kids, Cats and Concepts: Toward a Grand Unified Theory of ... Presentation Transcript

  • Kids, Cats and Concepts: Toward a Grand Unified Theory of Thinking Geoff Norman
  • The Goal
    • To link research in three domains:
      • Dual processing models of thinking
      • Exemplar and prototype models of categorization / concept formation
      • Expertise and clinical reasoning
    • to a greater understanding of human information processing
  • How I got there
    • Distant
      • Studies of clinical problem-solving
    • Intermediate
      • Role of experience in clinical reasoning
    • Recent
      • Diagnostic errors and “dual processing”
  • A Difficult Diagnostic Task
  •  
  • An Easy Diagnostic Task
  •  
  •  
  •  
  • What are all these things?
    • chairs,
    • (of course)
    • What makes something a chair?
    • What does the chapter on chairs in:
    • Harrison’s Textbook of Internal Design
    • look like?
    • (What are the signs and symptoms of chairs)
  • The rule describes this….
  • Does it cover these…?
  •  
  •  
    • The rule is insufficient for the classification task
    • But we can do the task quickly, accurately, and effortlessly
    • HOW?
  • The Role of Similarity
  • Which is this most like?
  • Perceptual similarity - holistic Perceptual Similarity The two objects share common characteristics - similar colouring, similar overall shape, wings / flippers, tail - fin. They look the same. Available without analytical knowledge : Pattern recognition, holistic processing
  • Causal similarity, conceptual Conceptual Similarity The two objects share common conceptual features (mammals) - live birth, lactation, lungs, livers, etc. Available only with specific analytical knowledge : Causal reasoning
  • Functional / Feature similarity Function/feature Shared features - dorsal fin, tailfin, body shape. Shared functio movement in water, size, eat fish Available either from perceptual similarity or individual features They look a lot alike Size, shape, etc.
  • Which is this most like?
  • Perceptual similarity - holistic The two objects share common characteristics - similar colouring, similar overall shape, wings / flippers, tail - fin. Swim underwater. Eat fish. Air breathing Available without analytical knowledge : Pattern recognition, holistic processing
  • Conceptual similarity The two objects share common conceptual features (mammals) - live birth, lactation, lungs, kidneys, etc. Available only with specific analytical knowledge : Causal reasoning
  • DUAL PROCESSING Two basic strategies
    • System 1
      • Based on holistic similarity to prior examples
        • “ Exemplar theory” (more later)
    • System 2
      • Based on underlying conceptual characteristics
        • “ Causal models”
  • System 2 thinking Playing by the rules
  •  
  • Analytic View of Expertise
    • “ The matters that set experts apart from beginners are symbolic, inferential, and rooted in experiential knowledge…Experts build up a repertory of working rules of thumb or “heuristics” that, combined with book knowledge, make them expert practitioners.”
    • E. Feigenbaum. The fifth generation: artificial intelligence and Japan's computer challenge to the world. 1983
  • System 1 thinking I’ve seen it before and here it comes again
  •  
  •  
  •  
    • Successful categorization
      • From 2-D abstract representation
      • without analysis of features
      • without language
    • Successful generalization
      • To other 2 D abstraction in atypical orientation
  • The Non- Analytic View
    • “ We must be prepared to abandon the traditional view that runs from Plato to Piaget and Chomsky that a beginner starts with specific cases and… abstracts and interiorizes more and more sophisticated rules.It might turn out that skill acquisition moves in just the opposite direction; from abstract rules to particular cases.” H.L. Dreyfus, 2002
  • Outline
    • Dual processing
    • Concept formation and categorization
    • Expertise and Clinical Reasoning
    • Applications -- Implications
    • Levels of Processing
    • Perception
    • Transfer
    • Aging and reasoning
    • Intelligence
  • Three Literatures Concept formation (categorization) Clinical Reasoning Dual Processing (Thinking) Medin,Brooks Norman,Schmidt Stanovich, Evans, Kahnemann
  • Dual Processing
    • System 1
    • Rapid, unconscious, based on concrete similarity, “just” pattern recognition
    • System 2
    • Slow, logical, conceptual, energy-intensive,
  • CHARACTERISTICS System 1 System 2
    • Unconscious
    • Implicit
    • Automatic
    • Effortless
    • Rapid
    • Holistic,
    • Old (evolution)
    • Contextualized
    • Conscious
    • Explicit
    • Controlled
    • Effortful
    • Slow
    • Analytic
    • New (evolution)
    • Abstract
  • Neuroanatomy of System 1,2
    • System 1
    • “ right inferior prefrontal cortex”
          • Evans, 2008
    • “ Involves hippocampus”
          • Smith & DeCoster, 2000
    • System 2
    • “ ventral medial prefrontal cortex”
  • Neurophysiology of System 1,2
    • Glucose dose (vs. Placebo)
    • Shift of processing strategy toward System 2 (more energy demand) with glucose load
    • (Attraction effect - 17% vs. 47%)
        • (Masicampo & Baumeister, 2008)
  • Mental representations
    • SYSTEM 1
      • Abstract concepts
        • Feature list, probability, causal mechanism, process
    • SYSTEM 2
      • ???????
  • Categorization / Concept Formation
  • Prototype Theory - Rosch, Mervis
    • Categories are defined by an abstracted prototype
      • Prototype has most features of category, fewest features of confuseable categories (Bird--> robin)
      • identification of category membership based on number of features in common with prototype
      • Retrieval process is “analytic”, hence based on relevant features
      • Retrieval process is deliberate, logical, slow
      • (Like System 2)
  • Exemplar Theory - Medin, Brooks
    • Categories consist of a collection of prior instances
      • identification of category membership based on availability of similar instances
      • Retrieval process is “non-analytic (unaware), hence can result from objectively irrelevant features
      • Retrieval process is not deliberate, not available to introspection
      • (Like System 1)
  • Dual Processing in Medicine From Process to Knowledge (Analytical and Experiential)
  • The beginnings - clinical reasoning as a process
    • “ Hypothetico-deductive method”
    • (Elstein, Shulman, Sprafka, 1977)
    • Expert (and novice) clinicians generate multiple diagnostic hypotheses early in the encounter then gather data to confirm (usually) these hypotheses
  • Does hypothesis predict accurate solution? Barrows, Neufeld, Norman, 1981
  • Where do hypotheses come from?
    • “ Medical experts differed from novices in that they generated better hypotheses……
    • and we don’t know why!”
    • A. Elstein
    • Dx Error Conference
    • May 31, 2008
  • Expert Physicians and Dual Processing
    • To what extent does the:
    • formal knowledge of medical school
    • vs.
    • experiential knowledge of practice
    • contribute to expertise
  • Schmidt & Norman, 1991 Basic Science Mechanisms Basic Science Mechanisms Basic Science Mechanisms Examples Clinical Rules Clinical Rules Novice Intermediate Expert System 2 System 1
  • Who do you pick?
    • Dr. JW completed the specialty exam last year and stood 14th in the country.
    • Dr. WS completed the specialty exam 6 years ago. At the time, she was in the top 1/3 of all candidates.
  • The Conundrum
    • Why do we prefer the candidate with apparently less “competence” but much more experience?
    • What did she get from 10 years of experience?
    • 10 years of experience s
    • (System 1 knowledge)
  • BUT
    • Every measure of formal (System 2) knowledge decays right after graduation
  • Day and Norcini, 1988
  • RESEARCH AGENDA The Role of Experience
    • In the course of becoming an expert, one requires an extensive stable of examples which guide diagnosis and management of new problems
    • How is this experiential knowledge stored and retrieved from memory?
    • How is this knowledge coordinated with analytical knowledge?
  • Evidence of System 1 in Diagnostic Reasoning
  • Visual Diagnosis and Response Time
    • STUDY
    • 100 slides in 20 categories
    • Students, clerks, residents, GPs, Dermatologist
    • Accuracy and Response Time
  • Accuracy by Educational Level
  • Response time by Educational Level
  • Evidence of Exemplars
  • Effect of Similarity (Allen, Brooks, Norman, 1992)
    • 24 medical students, 6 conditions
    • Learn Rules
    • Practice rules
    • Train Set A Train Set B
    • (6 x 4) x 5 (6 x 4) x 5
    • Test (9 / 30)
  •  
  •  
  • Accuracy by Bias Condition
    • Is it just visual similarity?
    • If it’s “non-analytic” does it apply to objectively irrelevant features?
  • ECG Interpretation Hatala et al, 1999
    • Medical students/ Fam Med residents
    • PRACTICE (4/4 + 7 filler)
      • middle aged banker with chest pain
      • OR
      • elderly woman with chest pain
        • Anterior M I
    • TEST ( 4 critical + 3 filler)
      • Middle aged banker with chest pain
        • Left Bundle Branch Block
  • RESULTS Percent of Diagnoses by Condition
  • CONCLUSIONS - Medical Diagnosis and Dual Processing
    • Experiential knowledge is a major contributor to diagnostic expertise
    • Categories and concepts are based on our specific experience with the world
    • These specific experiences are accessed and used without awareness
  • When do experts use system 2?
  • Analytic reasoning and Diagnosis
    • Invoked for confirmation in all Dx encounters
    • Analytic knowledge of many forms:
      • Illness scripts
      • Symptom-disease probabilities
      • Semantic axes
      • Feature lists (e.g. DSM 4)
  • Where Do Clinicians Use Basic Science?
    • Most use basic science rarely?
      • Observational studies (Schmidt, Patel)
    • Some use basic science some of the time
      • Difficult problems in nephrology
    • Some use physiology ALL the time
      • Intensivists, anesthesiology
  • Most use it rarely (Patel, Schmidt)
    • Clinicians rarely use basic science explanation in routine practice.
    • While they may possess the knowledge, it remains “encapsulated” until mobilized for specific goals (to solve specific problems) (Schmidt, HG)
  • Some Use it with Difficult Cases (Norman, Brooks, Trott, Smith)
    • When experts are confronted with difficult cases, do they revert to causal reasoning?
  • Experimental Design
    • R1 --GP R2 -- IM Nephrol
    • n=4 n=4 n=4
    • Clinical Cases
    • k = 8
    • Explain and Diagnose
  • Diagnostic Accuracy
  • Causal Explanations
  • No of Diagnoses / Investigations
  • Conclusions - Use of Basic Science
    • In difficult diagnostic situations, clinicians use causal physiological knowledge and analytic reasoning
    • Expertise associated with more coherent explanations, better diagnosis
  • Dual Processing and Experience
    • With increasing experience, do people rely more or less on System 1 -- Non-analytic reasoning?
  • Studies of Relative Experts (Moruzi, Brooks, Norman, 2003)
    • Dermatologists/ GPs / residents
    • 36 slides (typical / atypical)
    • Condition A
      • Verbal description of slide (verbal)
      • then photo (visual + verbal)
    • Condition B
      • Photo only (visual)
  • Diagnostic Accuracy
  • Diagnostic Accuracy
  • Hatala et al.
    • ECG Diagnosis
      • Prior match / unmatch history
      • Postgraduate residents and med students
  • RESULTS Percent of Diagnoses by Condition Medical Students
  • Dual Processing and Instruction
  • Role of Instruction in reasoning
    • Since NA (System 1) reasoning occurs at all levels, is effective, is “automatic”
    • You can’t:
    • tell student to not do it
    • tell student to beware of biases
    • tell student to think of better diagnoses
  • Does a coordinated strategy improve accuracy?
    • Norman, Brooks, Colle (ECG)
    • Schmidt and Mamede (Gen Medicine)
    • Ark & Eva, (ECG)
  • Norman, Brooks Colle, 2000
    • Contrast instructions to:
      • Think of the first thing that comes to mind, then consider features
      • vs.
      • Gather all the data then arrive at diagnosis
    • 32 Undergrad Psychology students
    • 11 disorders, rules + examples
    • Test -- 10 new ECG’s
  • Diagnostic Accuracy Pattern + Rules Rules
  • Schmidt & Mamede, 2005
    • 42 I.M. residents
    • 16 written cases --- simple / complex
    • Within subject/case design
    • Instructions:
    • “ First thing that comes to mind”
    • vs.
    • “ Hypotheses, findings for/against, differential, ….”
  • Diagnostic Accuracy
    • Does increased reliance on pattern recognition with experience have a cost?
  • Subjects: 39 medical students in McMaster MD Programme 3rd instructional unit (7 months completed). No prior training in dermatology   Materials Learn 10 cases Test on 20 new cases, matched / unmatched on similarity Instructions “ First thing” then “Carefully consider features” vs. “ Carefully list features and diagnose” Moruzi, Norman, Brooks, 2005
  • Combined vs. Individual Strategies
  • ECG Diagnosis - Ark & Eva
    • 48 undergrad psychology students
    • 8 ECG diagnoses (A/A’, B/B’, C/C’,D/D’)
    • Instructions
    • Compare and contrast vs. Sequential
    • Combined Analytical/Non-analytical vs.
    • usual approach
    • Test
    • 20 ECG’s (10 old, 10 new)
    • Immediate / 1 week later
  • Effect of Examples and Instructions on New Cases after One Week Ark & Eva, 2005
  • Conclusions - Dual Processing and Diagnosis
    • Evidence that clinicians access both kinds of knowledge/ use both processes
    • Evidence that with increasing experience, greater reliance on system 1
    • Evidence that students benefit from explicit instruction to use both
  • Dual Processing and Thinking
    • DP and levels of processing
    • DP and perception
    • DP and transfer
    • DP and aging
  • Dual Processing and Levels of Processing
    • Are conceptual structures and deep processing an underpinning to development of System 1 (non-analytic) knowledge?
    • (Dreyfus)
  • Role of Basic Science in Novice Reasoning (Woods, Brooks, Norman, 2003)
    • 4 neurology / muscular diseases
    • 36 medical students
    • Basic Science or Symptom/Disease probability
  • Measurement
    • Diagnostic Test
      • 15 cases, 4-6 features
    • Administered at 0, 7 days
  • Score on Dx Test
  • Score on Dx Test
  • Score on Dx Test
    • Basic science is used to construct and reconstruct coherent relations between symptom and disease
  • Dual Processing and Perception
  • Word Superiority Effect
    • Higher - level concepts (words) in memory facilitate recognition of elements of words and pseudo-words:
      • R I N K
      • B I N K
      • N R I K
      • - possibly because of rapid (top-down) then slow (bottom up) processing
  • Influence on Feature Interpretation
    • Diagnostic hypotheses arise from pattern recognition processes based on similarity to prior examples
    • In situations of feature ambiguity, hypotheses may influence what is seen
  • Influence of Diagnosis on Feature Perception (LeBlanc et al)
    • 20 residents, 20 final year students
    • 8 photos of classical signs from clinical diagnosis textbooks
    • Correct history and diagnosis
    • vs.
    • Incorrect history and diagnosis
  •  
  • RESULTS Diagnostic Accuracy by Bias
  • RESULTS Number of Features of Correct Diagnosis by Condition
  • RESULTS Number of Features of Alternate Diagnosis by Condition
  • Dual Processing and Transfer
    • Although medical (and other) study is directed at conceptual learning, use of conceptual knowledge to solve problems (transfer) is rare and difficult.
    • WHY????
  • Spontaneous Transfer
    • 8 high performing undergrad (Health Sciences) students.
    • 3 principles (Laplace, Poiseuille, Starling)
    • 12 test cases
    • Score
      • 0= wrong answer,
      • 1= right answer, wrong explanation
      • 2 = right answer, right but poor explanation
      • 3= right answer, good explanation
    • Laplace’s Law
    • In a cylindrical vessel, the wall tension is proportional to the radius and pressure exerted by the vessel contents. This can be expressed as T = PR where T is wall tension, P is pressure exerted by the contents, and R is the radius of the vessel.
        • A 72 year old female has been diagnosed with an aneurysm (dilatation) of the aorta. The doctor tells her that if it grows to 5 cm in diameter she will need surgery to prevent bleeding. Explain why the increasing diameter is a problem.
  • Average Score
    • 15.2/36 = 42%
    • “… during early learning, the principle is only understood in terms of the earlier example… the principle and example are bound together. Even if learners are given the principle or formula, they would use the details of the earlier problem in figuring out how to apply that principle to the current problem” (Ross, 1987)
  • Why are the examples so seductive?
    • System 1
    • Fast, unconscious, contextualized, concrete
    • System 2
    • Slow, logical, abstract
    • Transfer amounts to overriding System 1 to utilize abstract, conceptual information
  • DP and Age
    • Evidence from psychology that with increasing age, we rely more on System 1 thinking
  • Eva & Cunnington, 2006
    • 15 family docs, 7 < 60 yr., 8>60 yr.
    • 8 cases:
      • 2 diagnoses, 4 conditions
        • Generated, Provided, Privileged, Extreme
        • --------------->>>>>> weight on second diagnosis
  • Diff (Dx 1 - Dx2)
  • DP and Intelligence
    • The Flynn Effect
      • If the test is held constant, every generation scores about 8 IQ points higher than previous.
      • Why??
    • Vocabulary, math
    • - constant over generations
    • “ Similarities”
      • A mouse is to a horse as a minnow is to a:
        • Whale
        • Shark
        • Tuna
        • Elephant
    • large generational, cultural differences
    • Flynn:
      • - Generational differences reflect increasing use of concepts in society
      • - Nurture, not nature
  • Gardner, Sternberg
    • Triarchic theory of intelligence - Sternberg
    • Multiple intelligences - Gardner
    • People can be very “intelligent” in their own domain but cannot perform on abstract tasks in IQ test
  • Additional evidence
    • I.Q. is strongly related to size of working memory
    • System 2 loads heavily on working memory
    • System 1 independent of working memory
    • Does “conventional IQ” (or some aspects) reflect System 2?
    • Contextually imbedded intelligence reflect System 1
  • Some Last Words
    • (from other people)
    • {the expert} does not solve problems. He does not even think. He just does what normally works, and, of course, it normally works…. The expert is simply not following any rules! He is… discriminating thousands of special cases.
    • H Dreyfus
    • “ In general, to preserve expertise we must foster intuition at all levels of decision-making, otherwise wisdom will become an endangered species of knowledge.”
    • H. Dreyfus
  • First and Last Word on Expertise
    • “ It is a profoundly erroneous truism, repeated by all copy-books and by eminent people making speeches, that we should cultivate the habit of thinking about what we are doing. The precise opposite is the case. Civilization advances by extending the number of operations which we can perform without thinking about them. Operations of thought are like cavalry charges in a battle -- they are strictly limited in number, they require fresh horses, and must only be made at decisive moments.”
    • A.N. Whitehead, 1911 (in J Bargh, 1999)
  • Bibliography
    • Dreyfus HL From Socrates to expert systems: The limits and dangers of calculative rationality. http://socrates.berkeley.edu
    • Evans J St BT. In two minds: dual - process accounts of reasoning. Trends in Cognitive Science 2003; 7: 454-459
    • Evans J StBT. Dual processing accounts of reasoning, judgment and social cognition. Ann Rev Psychol 2008;59: 255-78.