Psychology 466:
Judgment & Decision Making
Psychology 466: Judgment & Decision Making
Instructor: John Miyamoto
10/01/2015: Lecture 01-1
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Outline
• General course information
• Get to know each other
• Psychology of judgment & decision making –
What is it?
• Background ideas from general cognitive psychology
Psych 466, Miyamoto, Aut '15
General Information re This Course
2
General Information
Instructor:
John Miyamoto
Email:
jmiyamot@u.washington.edu
Office:
215 Guthrie
Phone: 206-368-9761
Office hours: Thursday 12:00 – 1:00 in the Suzallo study room
across from the coffee shop (if you can't find me,
send me a text or phone message);
OR
make an appointment (contact by email or phone)
• UW computing provides JM with all student email addresses.
Let JM know if you use a non-UW email address.
Let JM know if you are not officially enrolled in this class.
Psych 466, Miyamoto, Aut '15
Textbooks
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Required Textbooks
• Hastie, R., & Dawes, R. M. (2009). Rational choice in an
uncertain world (2nd edition).
♦
Amazon prices: $68.40 in paperback.
• Kahneman, D. (2011). Thinking, fast and slow.
♦
Amazon price: $6.74 as a paperback.
• Hammond, J. S., Keeney, R. L., & Raiffa, H. (1998). Smart
choices: A practical guide to making better decision.
♦
Amazon price: $21.68 as a paperback.
• [Gigerenzer, G., & Brighton, H. (2009). Homo Heuristicus: Why biased
minds make better inferences. Topics in Cognitive Science, 1, 107-143.
pdf ]
There are ebook versions of these books (Kindle, possible epub).
Psych 466, Miyamoto, Aut '15
PDF’s On Psych 466 Website
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PDF’s for Week 1 Required Reading
• Hammond, J. S., Keeney, R. L., & Raiffa, H. (1998). Smart
choices: A practical guide to making better decisions.
Table of Contents, Preface & Chapter 1
• Hastie, R., & Dawes, R. M. (2009). Rational choice in an
uncertain world (2nd ed.). Table of Contents; Chapter 1;
Chapter 2;
• Gigerenzer, G., & Brighton, H. (2009). Homo Heuristicus: Why
biased minds make better inferences. Topics in Cognitive
Science, 1, 107-143.
• **NO PDF FOR KAHNEMAN**
PDF’s can be downloaded from the Psych 466 website.
Psych 466, Miyamoto, Aut '15
Reading Assignment for Week 1
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Reading Assignment for Week 1
• Chapters 1 & 2 of Hastie & Dawes (HD).
• Preface and Chapter 1 of Smart Choices.
• Gigerenzer, G., & Brighton, H. (2009).
Homo Heuristicus: Why biased minds
make better inferences. Pages 107 – 110.
A standard view of JDM
Applied Decision Making
Two Conflicting View
of Heuristic Reasoning
• Kahneman (2011). Thinking, Fast and Slow.
Pages 19 – 49.
♦
Ch 1: The characters of the story;
♦
Ch 2: Attention and effort;
♦
Ch 3: The lazy controller
Psych 466, Miyamoto, Aut '15
Psych 466 Website
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Psych 466 Website
• URL:
https://faculty.washington.edu/jmiyamot/p466/p466-set.htm
• Pdf’s of papers are posted here.
• Powerpoint lecture slides are posted here.
• Preview of the next lecture is posted here.
• Other stuff is posted here.
• All of this week’s readings are posted on the course website
as pdf’s.
Psych 466, Miyamoto, Aut '15
Assignments, Exams, Formula for the Course Grade
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Assignments and Exams
• One midterm exam and a final exam.
All exams are take-home exams.
Exam answers are submitted over the internet.
• Three short assignments.
% Grade
Assignments 1, 2 & 3
Psych 466, Miyamoto, Aut '15
9 (each)
Midterm
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Final Exam
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Course Website & Collect-It Website
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Course Website & Collect-It Website
• Course website
http://faculty.washington.edu/jmiyamot/p466/p466-set.htm
• Assignments and lecture notes will be posted.
• Catalyst Collect It website for turning in assignments & exams
https://catalyst.uw.edu/collectit/dropbox/jmiyamot/36460
Psych 466, Miyamoto, Aut '15
Get To Know Each Other
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Get to Know Each Other
Psych 466, Miyamoto, Aut '15
What is a Decision?
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What is a decision?
• Discuss
• Give some examples. Get some examples from the class.
Psych 466, Miyamoto, Aut '15
What is a Decision? – Some Examples
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What is a decision?
• Major reflective decisions:
♦
Whether or not to invest in a stock or business?
♦
Whether or not to buy a house? Which house to buy?
Similar buying decisions for other major items, e.g., cars, computers, etc.
♦
Whether to start a relationship with someone?
Whether to end a relationship with someone?
♦
Medical decisions – whether or not to have surgery for a problem?
• Low level decisions
♦
Shopping in a supermarket
♦
Which way to go when driving a car to a particular location
♦
What to wear today
• Neural decision making (by neural mechanisms in the brain)
Psych 466, Miyamoto, Aut '15
What Factors Do or Should Affect a Decision?
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• What factors that DO affect a decision?
• What factors that SHOULD affect a decision?
• Are there factors that affect decisions even though
they should not?
• Discuss
Psych 466, Miyamoto, Aut '15
General Description of Factor That Should Affect a Decision
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What factors that DO or SHOULD affect a decision?
Three concrete decision examples:
♦
Whether or not to take a particular course.
♦
Whether or not to buy a new, better computer.
♦
Whether or not to end a relationship with someone. Suppose the
relationship has a number of good features but also some bad features.
• What you want. Also, what you want to avoid.
How you feel about different ways the decision could turn out.
• How strong are your preferences (and dislikes) for particular
outcomes?
• What factors or events will affect whether the outcome
will be good, mediocre or bad, and to what degree?
• How likely are the different possibilities?
Psych 466, Miyamoto, Aut '15
Normative Decision Analysis – What Is It?
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Normative Decision Analysis
• Enumerate outcomes
• Enumerate options
• Construct a decision analysis for the decision
• Evaluate the probabilities of different possible outcomes
• Determine which option has the greatest "expected utility."
Psych 466, Miyamoto, Aut '15
What Are Typical Characteristics of Human Decision Making?
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What Are Typical Characteristics
of Human Decision Making
• Usually not analytic.
• Difficulty integrating feelings and thoughts
(affect and cognition).
• Fast. Reasonably accurate.
• Difficulties with complex information.
• Cognitive factors, e.g., limited memory, limitations on speed of
mental processing, limitations on available effort, ....
This course will help you be a better decision maker, especially
for careful, reflective decisions.
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History of the Psychology of Decision Making
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History of the Psychology of Decision Making
• Victorian rationality, Freudian irrationality,
behaviorist arationality.
• Expected utility theory (Von Neumann & Morgenstern, 1944)
Rational agent model of economic behavior
• Heuristics and biases movement, 1970 – 1990 (approx.)
• Reactions to heuristics and biases movement
Evolutionary psychology, ecological psychology, naturalistic decision making,
Bayesian models of psychological processes
• Psychology of happiness
• Separate development – neuroscience of decision making
(current hot topic!)
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The Cognitive Approach to Judgment & Decision Making
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Thursday, October 01, 2015: The Lecture Ended Here
• See <lec02-1.p466.a15.pptm>:
The lecture for the following Monday.
It has improved versions of the some of the following
slides.
Psych 466, Miyamoto, Aut '15
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The Cognitive Approach to Judgment & Decision Making
• Cognitive limitations – limitations on human cognitive capacity
affect judgment and decision making
• Heuristics and biases movement: 1970 – 1990 (approx.)
• Reactions to heuristics and biases movement
♦
Evolutionary psychology
♦
Ecological psychology
♦
Naturalistic decision making
♦
Bayesian models of psychological processes
♦
Emotion in decision processes
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The Standard Memory Model
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The Standard Cognitive Model of Human Memory
H&D
Fig. 1.1
Sensory Input Buffers
Working Memory
Central Executive
Phonological
Buffer
Goal
Stack
Visuospatial
Buffer
Long-Term Memory
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Sensory Registers
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H&D
Fig. 1.1
Sensory Input Buffers
Working Memory
Central Executive
Phonological
Buffer
Goal
Stack
Visuospatial
Buffer
Long-Term Memory
• Sensory registers retain the sensory information for very brief
periods of time.
Psych 466, Miyamoto, Aut '15
Working Memory
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H&D
Fig. 1.1
Sensory Input Buffers
Working Memory
Central Executive
Phonological
Buffer
Goal
Stack
Visuospatial
Buffer
Long-Term Memory
• Working memory (WM) holds a limited amount of information
for 10 – 20 seconds. Thoughts are actively manipulated in WM.
Psych 466, Miyamoto, Aut '15
Long-Term Memory22
H&D
Fig. 1.1
Sensory Input Buffers
Working Memory
Central Executive
Phonological
Buffer
Goal
Stack
Visuospatial
Buffer
Long-Term Memory
• Long-term memory (LTM) retains information over longer periods
of time. LTM interacts with WM.
Psych 466, Miyamoto, Aut '15
General Hypothesis of Cognitive Research
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H&D
Fig. 1.1
Sensory Input Buffers
Working Memory
Central Executive
Phonological
Buffer
Goal
Stack
Visuospatial
Buffer
Long-Term Memory
General Hypothesis of Cognitive Research
♦
Limitations in working memory impose limitations on human ability to
engage in complex reasoning.
♦
Decision making requires complex reasoning.
Psych 466, Miyamoto, Aut '15
Basic Message: Cognitive Limitations Produce Simplifications 24
Basic Message from Many Cognitive Studies
• LIMITED WM CAPACITY:
When information is complex, people are forced to simplify the
information. Simplifications can lead to distortions.
• Exception: Experience can teach one to integrate specific types
of complex information but only in some cases.
♦
Example: Expert chess players can reason about complicated chess
problems.
♦
Example: Experienced drivers can understand traffic situations that are
actually very complex.
• Next a complex representation of decisions under risk
(decision trees).
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Where We Are in the Lecture
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Where We Are in the Lecture
• Normative and prescriptive decision models
require complex representations and processing
• Cognitive limitations cause us to simplify decisions,
and this can produce errors
NEXT: How to Deal with Cognitive Complexity
• Intuitive clinical judgment versus statistical Models
• Brunswik’s Lens Model of Human Judgment
Next Lecture
• Linear models applied to making better choices
• Applications to clinical judgment
Psych 466, Miyamoto, Aut '15
Clinical vs Actuarial Jdmt
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Intuitive Judgment versus Acturial Judgment
• Intuitive judgment
♦
♦
Combine complex information in your head
Make decision based on gut feeling
• Actuarial judgment (a.k.a. statistical model or linear model)
♦
Base decisions on a statistical decision rule.
Psych 466, Miyamoto, Aut '15
Statistical Models Outperform Human Judges
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Examples of Judgment Problems
• We will only consider decisions to which intuitive judgment and
actuarial judgment (statistical methods) both apply.
-------------------------------------------------------------------------E.g., Clinicians attempt to identify patients with progressive
brain dysfunction.
♦
♦
♦
Data = intellectual test results
Experienced clinicians achieved 58% correct detection of new cases.
Statistical model achieved 83% correct detection of new cases.
• E.g., Bank loan officer must decide which loan applications are
“good risks” and which are “bad risks.”
• E.g., Professors must decide which applicants will do well in
grad school and which will not do well.
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Critique of Clinical Judgment – What Is It?
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Critique of Clinical Judgment
• Clinical insight – does it exist?
• Clinical judgment – what is it good for?
• Clinical judgment – what are its weaknesses?
• Accusation: Belief in the efficacy of intuitive clinical judgment
is a cognitive conceit.
Psych 466, Miyamoto, Aut '15
General Finding: Stat Models Outperform Human Judges
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General Finding: Stat Models Outperform Human Judges
• Statistical models almost always outperform the human judges
on clearly defined decision tasks.
• Human cognitive processes are good at noticing particular pieces
of information.
♦
Does my friend look happy? Sad? Stressed? Irritated?
♦
Is the patient nervous? Defensive? Exhibitionistic?
• Human cognitive processes are not good at integrating
multiple pieces of information.
♦
Can I predict how my friend will feel about a surprise party?
♦
Can the clinician predict how the patient will progress after 4 months
of therapy?
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Implications of this Lecture / END
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Implications of this Lecture
• We can improve human decisions by stressing what humans are
good at:
... noticing what are important issues that are relevant to a
decision;
... evaluating how good or bad is an outcome on a specific
dimension;
while avoiding what we are not good at:
... combining complex information in our heads.
• Know thyself → Make better decisions
• NEXT WEEK: Linear models of human judgment ......
and what they tell us about us!
Psych 466, Miyamoto, Aut '15
END
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