1. The Psychology of Inductive Inference
Psychology 355: Cognitive Psychology Instructor: John Miyamoto 05/24/2018: Lecture 09-4
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2. Lecture probably ends here
Outline
Deductive and inductive reasoning
Expected utility theory - the normative theory of rational action
The heuristics & biases research program
The availability heuristic – What is it?
The representativeness heuristic – What is it?
Lecture probably ends here
Psych 355, Miyamoto, Spr ‘18
Introduction to Reasoning

3. Introduction to Reasoning
Deductive & inductive inference - what are they?
Expected utility theory - the normative theory of rational action
The heuristics & biases research program - what is it?
The availability heuristic – What is it?
The representativeness heuristic – What is it?
Psych 355, Miyamoto, Spr '18
2 x 2 Table Showing Contrast between Deductive & Inductive Inference

4. Deductive and Inductive Inference
Psych 355, Miyamoto, Spr '18
Focus on Deductive Inference

5. Deductive Reasoning Examples of deductive reasoning:
Math problem solving
Logic problems
Some aspects of physics problem solving; and other natural science problem solving
Four Card Problem
Psych 355, Miyamoto, Spr '18
Definition of Inductive Reasoning

6. Inductive Reasoning Examples of inductive reasoning:
How likely is it that it will rain tomorrow in Seattle?
How likely is it that the defendant in a criminal trial is guilty?
What do the results of an experiment imply about a hypothesis that is tested in the experiment?
Economic forecasts: How likely is a recession in Europe during 2019/2020?
Based on what we know about American history, politics and culture, what is likely to happen in the next national elections?
Psych 355, Miyamoto, Spr '18
Why Psychologists Are Interested in Inductive Reasoning

7. Why Psychologists Are Interested in Inductive Reasoning
Most real-world questions involve uncertainties. How do people make decisions when faced with risk and uncertainty?
Rational decision model: Expected utility theory
Bayesian decision theory
Central assumption of economic theory & business decision making: Rational decision makers obey the Bayesian decision theory.
Heuristics & biases research: Cognitive critique of the rational agent model.
Modern behavioral economics
General issue of how humans acquire knowledge from uncertain information.
Psych 355, Miyamoto, Spr '18
Psychology of Risk – What Are Basic Issues?

8. Psychology of Risk and Likelihood – What Are Basic Issues?
How do people make decisions when faced with risk and uncertainty?
Example: Deciding whether to buy a house. Deciding which house to buy among the available choices.
Example: Deciding what medical treatment is best for a given patient (maybe yourself; maybe for someone else).
How do people judge the likelihood of events?
Example: How likely is it that North Korea will sell nuclear technology to other terrorists?
Example: How likely is it that you will find a good job if you pursue a career in X, e.g., marketing?
How do people judge how much they like or dislike particular possibilities? How do people predict their future preferences?
Psych 355, Miyamoto, Spr '18
Basic Elements of a Rational Decision Model

9. Basic Elements of a Rational Decision Model
All decisions can/should be represented as choices between gambles. Every possible action should be represented as a specific gamble.
Mathematicians, economists and philosophers have identified rules of reasoning that govern how a rational agent would choose a best course of action (best gamble) from the available actions.
Psychological Issues in the Critique of Rational Decision Models
How do humans perceive risks? How do humans respond to risks?
How do humans evaluate uncertainties?
How do humans evaluate the relative strength of preference for different outcomes.
Psych 355,, Miyamoto, Spr '18
Rational Decision Model & JDM

10. Rational Decision Model & JDM
Rational decision model: Expected utility theory
Bayesian decision theory
Central assumption of economic theory & business decision making: Rational decision makers obey the Bayesian decision theory.
Judgment & Decision Making (JDM) – a branch of cognitive psychology; generally critical of the rational decision model
Human cognitive processes lead to counterproductive (suboptimal) judgments and decisions
Heuristics & biases research: Cognitive critique of the rational agent model.
Heuristics & biases research program is a major part of JDM research.
Psych 355, Miyamoto, Spr '18
Definition - Heuristic Reasoning Strategies

11. Heuristic Reasoning Strategies
Heuristic reasoning strategies – reasoning strategies that are useful because they are easy and generally effective, even though they can sometimes lead to errors.
Psych 355, Miyamoto, Spr '18
Main Claims of the Heuristics & Biases Movement

12. Main Claims of the Heuristics & Biases (H&B) Movement
Human cognitive processes do not follow the pattern of a rational model.
(Rational model = expected utility theory & Bayesian decision model)
Human decision making uses heuristic strategies that are useful, but they can lead to systematic errors.
Heuristic reasoning strategies ....
.... are often fast and effective,
.... place low demands on cognitive resources.
.... but they can lead to errors in particular situations.
Behavioral economics – the application of cognitive psychology to the analysis of economic behavior.
Psych 355, Miyamoto, Spr '18
Heuristic Reasoning Strategies - Definition

13. Some Heuristics in Inductive Reasoning
Availability
Representativeness
Anchoring & Adjustment
Confirmation bias
Focusing illusion
Framing effects
Mental accounting
More heuristics that have been proposed than are listed here.
Psych 355, Miyamoto, Spr '18
Availability Heuristic

14. Availability Heuristic
Frequency of Experience
Other Factors
Availability of Memory for an Event
Learning
Judged Likelihood of a Similar Event
Judgment
Availability heuristic – events are judged more probable if similar events are easy to recall or easy to imagine.
In general, frequently encountered events are easier to recall.
The availability heuristic exploits the converse of this relationship: Events that are easy to recall are thought to be frequent in occurrence.
Availability heuristic causes biased probability judgments when other factors that influence availability are not taken into account.
Psych 355, Miyamoto, Spr '18
Same Slide Without Emphasis Rectangles

15. Availability Heuristic
Frequency of Experience
Other Factors
Availability of Memory for an Event
Learning
Judged Likelihood of a Similar Event
Judgment
Availability heuristic – events are judged more probable if similar events are easy to recall or easy to imagine.
In general, frequently encountered events are easier to recall.
The availability heuristic exploits the converse of this relationship: Events that are easy to recall are thought to be frequent in occurrence.
Availability heuristic causes biased probability judgments when other factors that influence availability are not taken into account.
Psych 355, Miyamoto, Spr '18
Availability: Lists of Famous & Non-Famous Names

16. Condition I: Famous Male Non-Famous Female
Availability Bias Due to Ease of Encoding Famous/Non-Famous Names x Male/Female
Condition I: Famous Male Non-Famous Female
Bill Clinton Tom Hanks Michael Jordan
Mary Brooks Andrea Forbus Leanne Faris
Condition II: Famous Female Non-Famous Male
William Hale Murray Jencks Lionel Worley
Michelle Obama Angelina Jolie Sarah Palin
Subjects saw a list of names, one at a time, that mixed famous males with non-famous females, or vice versa. There were 18 famous and 19 non-famous names in the list.
Psych 355, Miyamoto, Spr '18
Next: Same Slide with No Barriers & Results

17. Results: Famous/Non-Famous Names x Male/Female
Condition I: Famous Male Non-Famous Female
Bill Clinton Tom Hanks Michael Jordan
Mary Brooks Andrea Forbus Leanne Faris
Condition II: Famous Female Non-Famous Male
William Hale Murray Jencks Lionel Worley
Michelle Obama Angelina Jolie Sarah Palin
Results:
Subjects reported that the list had more males than females, if the males were famous;
Subjects reported that the list had more females than males, if the females were famous;
Availability influences perceived frequency.
Psych 355, Miyamoto, Spr '18
Reminder of Link to Memory Model

18. Availability Heuristic
Frequency of Experience
Other Factors
Availability of Memory for an Event
Learning
Judged Likelihood of a Similar Event
Judgment
“Other Factors” that influence availability of a memory
Famous names are easy to encode and easy to retrieve. Non-famous names are harder to encode and harder to retrieve.
Psych 355, Miyamoto, Spr '18
Egocentric Bias - Intro

19. Egocentric Bias (Example of Availability Heuristic)
Egocentric bias: People overestimate the proportion of the total work that they have contributed to a project.
Ross & Sicoly (1979): Subjects were 37 married couples.
Working separately, husband and wife rated self and spouse for their work on 20 activities: making breakfast; cleaning dishes; cleaning house; making important decisions; ... ; causing arguments between themselves; making the house messy; irritating spouse.
primarily primarily husband wife
Psych 355, Miyamoto, Spr '18
Predicted Response Pattern If No Bias Existed

20. Rating Procedure in Egocentric Bias Study
Husband and wife rated self and spouse for their work on 20 activities
primarily primarily husband wife
Subjects rated their responsibility on a line as shown above.
Husband's rating measured as distance from the right end; wife's ratings measured as distance from the left end.
If husband and wife have accurate perceptions of responsibility, the sum of their ratings should equal the length of the line.
Wife's Mark
Husband's Mark
Husband's Rating of Self
Wife's Rating of Self
Psych 355, Miyamoto, Spr '18
Predicted Response Pattern If No Bias Existed

21. Example: Suppose that Husband & Wife's Ratings Are Consistent With Each Other
Husband and wife agree as to contribution of each to a task like washing dishes:
primarily primarily husband wife
If husband and wife were not egocentric, the couple's ratings would sum to +100.
▐ + 25 in husband's scoring ▐ + 75 in wife's scoring
+100 total of husband & wife
_________________________
Psych 355, Miyamoto, Spr '18
Predicted Response Pattern If Egocentric Bias Exists

22. Example: Suppose that Husband & Wife's Ratings Are Inconsistent With Each Other
Husband and wife disagree about their contributions to washing dishes.
primarily primarily husband wife
If husband and wife are egocentric, the couple's ratings would sum to more than 100.
▐ + 45 in husband's scoring ▐ + 75 in wife's scoring
+120 total of husband & wife
_________________________
Psych 355, Miyamoto, Spr '18
Results for Egocentric Bias Study

23. Results for Egocentric Bias Study
The inconsistent pattern is typical: On many activities, ....
The result holds for both good things (wash the dishes) and bad things (buy unnecessary things).
This pattern suggests an excessive attribution to the self of both credit and blame.
Husband’s Rating + Wife’s Rating > 100
Psych 355, Miyamoto, Spr '18
Why Do Couples Have an Egocentric Bias?

24. Why Do Couples Have an Egocentric Bias?
Is egocentric bias due to some aspect of male/female relations? Or is it due to something specific to male/female couples?
Probably not.
Self versus supervisor focus in attributing responsibility for BA thesis work.
Basketball players attributing responsibility for wins or losses.
Egocentric bias is probably due to the greater availability of self-actions than partner actions.
Death from asthma more likely than death from tornado, but people make opposite prediction. Death from appendicitus more likely than death from pregnancy, but people make opposite prediction.
Psych 355, Miyamoto, Spr '18
Sampling Bias in Everyday Media

25. Thursday, 24 May, 2018: The Lecture Ended Here
Psych 355, Miyamoto, Spr '18

26. Sampling Bias in Everyday Media
Biases in Information Sources
Biases in Availability
Biases in Perceived Likelihood of Events
Things we all know:
TV ads do not give an accurate picture of the value of products.
Political spin doctors are trying to manipulate our beliefs.
TV news is emphasizes dramatic events; it ignores undramatic events.
The portrayal of men/women, black/whites, rich/poor, gay/straight, on TV is not a representative presentation of these groups.
Our own experiences are not typical of everybody’s experience.
Etc.
We all know that these information sources are biased, but can we really correct for these biases when forming beliefs? Doubtful.
Insensitivity to sampling bias (exposure bias) is not strictly a cognitive bias. The world is biased, but we have difficulty taking this into account.
Psych 355, Miyamoto, Spr '18
Return to the Diagram of the Availability Heuristic & List of “Other Factors”

27. “Other Factors” that Influence the Availability of Events
Egocentric bias.
Dramatic events seem more common than non-dramatic events.
Biases in the media create biases in the availability of stereotypes.
Recent events seem more common than earlier events.
Anything that makes events easier to encode or retrieve can make the events seem more frequent than they are.
Conclude with remarks re the importance of probability judgment in decision making.
Tomorrow: Representativeness heuristic
Psych 355, Miyamoto, Spr '18
Summary re the Availability Heuristic - END

28. Summary re the Availability Heuristic
Judging probability in terms of availability is a heuristic.
I.e., it is generally a reasonable way to estimate likelihood, but it can lead to certain systematic errors.
Factors that are not related to experienced frequency can make make particular events more available.
E.g., the perceived probability of being killed by a random crazy person will tend to be exaggerated if biased news and cognitive biases make this kind of event more available than more mundane events.
Psych 355, Miyamoto, Spr '18
END