Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Chapter 12: Decision
Making and Reasoning
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Decision Making
• 2 different types of models for decision
making
– Prescriptive models
• Models describing the best way to make a decision
– Descriptive models
• Models describing the way decisions are actually
made
• Cognitive psychologists are interested in
how people actually make decisions
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Classical Decision Theory
• Assumed decision makers
– Knew all the options available
– Understood pros and cons of each option
– Rationally made their final choice
– Goal was to maximize value of decision
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Howard’s Dilemma
• Thagard & Milgram (1995)
– “An eminent philosopher of science once encountered a noted
decision theorist in a hallway at their university. The decision
theorist was pacing up and down, muttering, ‘What shall I do?
What shall I do?’
– ‘What's the matter, Howard?’ asked the philosopher.
– Replied the decision theorist, ‘It's horrible, Ernest - I've got an
offer from Harvard and I don't know whether to accept it.’
– ‘Why Howard,’ reacted the philosopher, ‘you're one of the world's
great experts on decision making. Why don't you just work out the
decision tree, calculate the probabilities and expected outcomes,
and determine which choice maximizes your expected utility?’
– With annoyance, the other replied, ‘Come on, Ernest. This is
serious.’ ”
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Subjective Utility Theory
• Goal
– Seek pleasure and avoid pain
– Actual judgment of pleasure and pain is
made by each decision maker (subjective)
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Subjective Expected Utilities
• Consider all possible alternatives
• Use all information currently known
• Weigh potential costs and benefits
• Subjective weighing of various
outcomes
• Sound reasoning consider above
factors
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Satisficing
• To obtain an outcome that is good
enough
• Term introduced by Herbert A. Simon
in his Models of Man 1957
– Simon noted that humans are rational but
within limits (bounded rationality)
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Elimination by Aspects
• Tversky (1972)
– Begin with a large number of options
– Determine the most important attribute and then
select a cutoff value for that attribute
– All alternatives with values below that cutoff
are eliminated
– The process continues with the most important
remaining attribute(s) until only one alternative
remains
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Group Decision Making
• Can enhance decision making
• More ideas
• Better memory of events
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Disadvantage of Group Decisions
• Groupthink
– Premature decision made by members
trying to avoid conflict
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Symptoms of Groupthink
• Closed-mindedness
• Rationalization
• Squelching of dissent
• Formation of “mindguard”
• Feeling invulnerable
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Heuristics Influencing Decision Making
• Representativeness
• Availability
• Anchoring & adjustment
• Overconfidence
• Illusory correlation
• Hindsight bias
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Making Decisions
• Chris is 6’7”, 300 pounds, has 12
tattoos, was a champion pro wrestler,
owns nine pit bulls and has been
arrested for beating a man with a
chain.
– Is Chris more likely to be a man or a
woman?
– A motorcycle gang member or a priest?
– How did you make your decision?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Making Decisions
• Steve is meek and tidy, has a passion
for detail, is helpful to people, but has
little real interest in people or realworld issues.
– Is Steve more likely to be a librarian or a
salesperson?
– How did you come to your answer?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Making Decisions
• Linda is a 31-year-old, single, outspoken,
and very bright person. She majored in
philosophy. As a student, she was deeply
concerned with issues of discrimination and
social justice, and also participated in
antinuclear demonstrations.
– What is the probability that Linda is a bank
teller?
– What is the probability that Linda is a feminist
bank teller?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Representativeness Heuristic
• Judge probability of an event based on
how it matches a stereotype
• Can be accurate
• Can also lead to errors
• Most will overuse representativeness
– i.e. Steve’s description fits our vision of a
librarian, Linda seems to be more of a
feminist
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Representativeness Heuristic
• Gambler’s Fallacy
– Mistaken belief that a random event is
affected by previous random events
– Believe that “your turn to win” has come
– In reality, probability to win is still same
probability
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Base rate Information
• The actual probability of an event
– How many bank tellers are there in the world?
– How many feminists are there?
• Much research in the 1970’s &1980’s seemed to
•
indicate that base rate information in these type
of problems were ignored
Current research focuses on when participants
do pay attention to base rates
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Koehler (1996)
• Base rates are used when
– Problems are written in ways that
sensitize decision-makers to the base rate
– Problems are conceptualized in relative
frequency terms
– Problems contain cues to base rate
diagnosticity
– Problems invoke heuristics that focus
attention on the base rate
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Making Decisions
• Which are you more afraid of?
– Flying in an airplane
– Driving in a car
• Meyers (2001)
“The Air Transport Association reports that 483
passengers were killed in plane crashes from 19951999 (97 per year). During these years, the National
Safety Council's Research and Statistics Department
tells me, we were 37 times safer per passenger mile in
planes than motor vehicles.”
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Availability Heuristic
• Making judgments about the frequency
or likelihood of an event based on how
easily instances come to mind
• Actual frequency influences how easily
evidence comes to mind but so do
other factors
– Media
– Vividness
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Schwartz (1991)
• Manipulated how many instances participants
had to give of previously being assertive
– One group had to recall six examples of when
they had been assertive
– A second group had to think of twelve examples
– Both groups were then asked to score their
assertiveness
– Participants who thought of six examples scored
themselves higher than the group that had
difficulty thinking of twelve examples
– Pattern of results attributed to the availability
heuristic
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Anchoring-and-Adjustment Heuristic
• Begin by guessing a first
approximation (an anchor)
• Make adjustments to that number on
the basis of additional information
• Often leads to a reasonable answer
• Can lead to errors in some cases
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Anchoring-and-Adjustment
• People are influenced by an initial
anchor value
• Anchor value may be unreliable,
irrelevant, and adjustment is often
insufficient
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Anchoring-and-Adjustment
• Participants asked to calculate in 5 secs
the answer to one of the following
problems:
– 1 x 2 x 3 x 4 x 5 x 6 x 7 x 8= 512
– 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1= 2,250
• The order of presentation for these two
groups had a significant impact on their
estimates
• The correct answer, in both cases, is
40,320!
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Effect of Framing on Decisions
• Which choice would you make?
– Suppose you have invested in stock equivalent to the
sum of $60,000 in a company that just filed a claim
for bankruptcy. They offer two alternatives in order
to save some of the invested money:
• If Program A is adopted, $20,000 will be saved
• If Program B is adopted, there is a 1/3 probability that
$60,000 will be saved and a 2/3 probability that no money
will be saved
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Rönnlund, Karlsson, Laggnäs, Larsson, &
Lindström (2005)
• Examined the impact of framing on risky
decisions
• Manipulated age (young/older) and type
of framing (positive/negative)
• Participants read one of 3 scenarios
• Participants selected either a risky or
certain outcome
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Sample Scenario
•
•
•
Suppose you have invested in stock equivalent to the sum of
$60,000 in a company that just filed a claim for bankruptcy.
They offer two alternatives in order to save some of the invested
money:
Positive Framing
– If Program A is adopted, $20,000 will be saved (certain outcome)
– If Program B is adopted, there is a 1/3 probability that $60,000 will be
saved and a 2/3 probability that no money will be saved (risky outcome)
Negative Framing
– If program A is adopted $40,000 will be lost (certain outcome)
– If program B is adopted, there is a 1/3 probability that no money will be
lost, and 2/3 probability that $60,000 will be saved (risky outcome)
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Try It!
•Write your name on a piece of paper and indicate the truth of
the following statements
– 1 means you are sure it is true, 10 means you are sure it is false
Truth
Rating
1. Martin Luther King was 39 when he died.
2. The gestation period of an Asian elephant is 225 days.
3. The earth is the only planet in the solar system that has one moon.
4. The number of lightning strikes in the United states per year is 25
million.
5.The Rhöne is the longest river in Europe.
Collect the sheets.
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Try It Answers
• Martin Luther King was 39 when he died
• The gestation period of an Asian elephant is
•
•
•
not 225 days--It is 645 days
The earth is the only planet in the solar
system that has one moon. False, Pluto also
has one moon
The number of lightning strikes in US is
approximately 25 million
The Rhöne is not the longest river in Europe
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Illusory Correlations
• An illusory correlation is a perceived relationship
that does not, in fact, exist
• Illusory correlations are formed by the pairing of
two distinctive events
–
–
–
–
Redelmeier and Tversky (1996)
18 arthritis patients observed over 15 months
The weather was also recorded
Most of the patients were certain that their condition
was correlated with the weather
– The actual correlation was close to zero
• What illusory correlations may affect your
decisions?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Demonstration- Future events
•
•
Predict whether you will experience these events
this semester
1.
2.
3.
4.
5.
6.
Obtain an A in your favorite course.
Have an out-of-town friend visit you.
Lose more than ten pounds.
Drop a course after the 5th week.
Be the victim of a crime.
Get a parking or speeding ticket.
How confident are you of your judgment for
each item? (100%, 80%, 60%.....)
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Overconfidence
• People tend to have unrealistic optimism
•
about their abilities, judgments and skills
Examine your confidence judgments about
future events asked on a previous slide—are
you confident your judgments are accurate?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Dunn & Story (1991)
• Examined overconfidence of students
– At beginning of the semester students were
given 37 items like the ones on the previous
slide
– At end of the semester, students were asked to
indicate which events had actually occurred
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Dunn & Story (1991)
• Results indicated that all students exhibited
•
•
large tendencies toward overconfidence
Confidence influences how we make
decisions, yet our confidence may not be
based on a realistic estimate of events or
skills
Why is this a problem?
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Try it again…Predict your past answer
1 means you were sure it was true
10 means you were sure it was false
Your past
answer
1. Martin Luther King was 39 when he died.
2. The gestation period of an Asian elephant is 225 days.
3. The earth is the only planet in the solar system that has one moon.
4. The number of lightning strikes in the United states per year is 25
million.
5.The Rhöne is the longest river in Europe.
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Hindsight Bias
• The memory of how we acted
previously changes when we learn the
outcome of an event
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Hindsight Bias
• Reconstruction after feedback theory
(RAFT)
– Proposed by Hoffrage,Hertwig &
Gigerenzer (2000)
– Allows us to remove clutter by tossing
out inaccurate information and embracing
the right answers in our memory
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Do People Reason Logically?
• Deductive reasoning
– Formal procedure that ensures accuracy if rules
of logic are followed
– Given some premises that are true, one can
reach a conclusion that must also be true
– Example:
• All men are mortal.
• Socrates is a man.
• Therefore, Socrates is mortal.
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Deductive Validity
• How do we know when an argument is
valid?
• Typically deductive arguments have
three statements:
– If P, then Q (Conditional if-then statement)
– Statement about whether P or Q is true or
not true
– A conclusion about P or Q
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Two Valid Deductive Inferences
• Modus Ponens
– If P, then Q
– P is true
– Q is true
All fruit grows on trees
An apple is a fruit
Therefore, apples grow on trees
– If P, then Q
– Not Q
– Not P
All fruit grows on trees
Tomatoes do not grow on trees
Therefore, tomatoes are not a fruit
• Modus Tollens
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Two Deductive Fallacies or Errors
• Denying the antecedent
– If P, then Q
– Not P
– Not Q
All fruit grows on trees
Tomatoes are not a fruit
Therefore, tomatoes do not
grow on trees
• Affirming the consequence
– If P, then Q
–Q
–P
All fruit grows on trees
Acorns grow on trees
Acorns are fruit
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Wason Card Selection Task
A
2
X
3
• Each card has a letter on one side and a digit on
the other. Determine by turning over the
minimum number of cards if this rule is true: If
there is a vowel on one side, there is an even
number on the other side.
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Wason Selection Task
A
2
X
3
• If vowel then even number on the other side
– Must turn over A (Modus Ponens)
•
•
Most get this card right, confirmation bias
Because a vowel, want to see if even number of other side
– Must turn over 3 (Modus Tollens)
•
•
Only 15% of college students get this correct
Must be sure there is not a vowel on the other side
– 2 card doesn’t matter
•
Rule does not state that all even numbers have to have vowels
– X card doesn’t matter.
•
Rule does not specify anything about consonants.
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Syllogistic Reasoning
Statement 1: All men are animals
Statement 2: Some animals are aggressive
Conclusion: Some men are aggressive
This seems to be a reasonable conclusion, but then consider the following:
Statement 1: All men are animals
Statement 2: Some animals are female
Conclusion: Some men are female
Now the conclusion appears to be ridiculous and false
- yet the reasoning is exactly the same as in the first example.
Thus, the first example has a false conclusion.
The animals who are aggressive are not necessarily men.
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Griggs & Cox (1982)
Beer
22
Coke
• Four people are sitting at a table.
17
Who do
you question to determine whether the law
is being broken? If a person is drinking
beer, then the person must be 21 or over.
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Pragmatic Reasoning Schema
• Cheng & Holyoak (1985)
– Theorized a permission schema exists that helps
to solve the problem
– Once activated, the schema enables the person
to determine what evidence is necessary to
evaluate the rule
– Activated by a context that involves permission
• To use the pool, you must be a patron of the hotel
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Cheng & Holyoak (1985)
• Reframed the Wason card selection
task in the form of a permission
statement
• Found that 61% of college students
now got the problem correct versus
only 19% when the problem was not
framed in terms of permission
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Syllogistic Reasoning
• Draw a conclusion based on two
premises
– A major premise
– A minor premise
– A conclusion
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Syllogistic Reasoning
True Categorical Syllogism
All men are animals
Some animals are aggressive
Some men are aggressive
False Categorical Syllogism
All men are animals
Some animals are female
Some men are female
The second conclusion appears to be ridiculous and false
- yet the reasoning is exactly the same as in the first
example. The first example thus has a false conclusion.
The animals who are aggressive are not necessarily men
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
How do People Solve Syllogisms?
• Mental Model
– A mental model represents one
possibility, capturing what is common to
all the different ways in which the
possibility may occur.
– Mental models represent explicitly what
is true, but not what is false. These
characteristics may lead to systematic
errors.
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Working Memory and Syllogisms
• Gilhooly & Associates (1993)
• Present syllogisms orally or visually
• Oral presentation leads to heavier load
on working memory
• Participants in the oral presentation
performed more poorly.
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Obstacles to Deductive Reasoning
• Overextension errors
• Foreclosure errors
• Confirmation bias
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Enhancing Deductive Reasoning
• Avoid heuristics and biases that distort
our reasoning
• Consider more alternatives
• Training and practice
• Being sad
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Evolutionary View
• Cosmides & Tooby (1996)
– Humans are social animals
– Humans have evolved to deal well with
social rules
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Inductive Reasoning
• Involves reasoning from specific cases
to more general, but uncertain,
conclusions
– Cannot reach a conclusion with 100%
accuracy
– Can reach a highly probable outcome
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
How People Make Causal Inferences
• John Stuart Mill’s Cannons
– Method of Agreement
– Method of Difference
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Schustack & Sternberg (1981)
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Schustack & Sternberg (1981)
Results
• Indicated 4 pieces of information were
used to determine causality
– Joint presence of possible cause and
outcome
– Joint absence of cause and outcome
– If one was absent and other was present
then no causality
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Confirmation Bias
• Tendency to search for and interpret
evidence in a way that confirms our
theories and avoid evidence that
contradicts prior beliefs
– E.g., Self-fulfilling prophecy
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Deductive vs. Inductive Reasoning
•
•
Turvey (1999) provides example of each type of reasoning in a
forensic context
Deductive reasoning
•
Inductive reasoning
– Fingerprint in blood is on knife
– Fingerprint belongs to D
– Therefore, D was in contact with knife after victim began to bleed
– 85% of known killers who use severe blunt force trauma to the faces of their
victims live with their mother
– 75% of known killers who tie up their victims during a crime are between the
ages of 25-31, drive a 4x4 truck, are white, and are highly intelligent
– Therefore, the offender may be a white male, age 25-31, who lives with his
mother, and drives a 4x4 truck.
Cognitive Psychology, Fifth Edition, Robert J. Sternberg
Chapter 12
Alternate View of Reasoning
• Sloman (1996)
– Two complementary systems of reasoning
• Associative system
• Rule-based system