Lecture 11

Question 0

What is induction?

Answer 0

Provides probabilistic evidence

Question 1

What is deduction?

Answer 1

If the premises are valid then conclusion must be true

Question 2

What is syllogistic reasoning?

Answer 2

Syllogism consists of two premises followed by a conclusion

Inference is valid if conclusion follows necessarily from the premises given

Question 4

What is the modus ponens rule

Answer 4

If p then q, therefore q.

All bananas are yellow. This is a banana. Therefore it is yellow

Question 5

What is affirming the consequent (errors)

Answer 5

If p then q, therefore p.
All bananas are yellow
This is yellow
Therefore it is a banana

Question 6

What is the modus tollens rule?

Answer 6

If p then q
Not q
Therefore not p

All bananas are yellow
This is not yellow
Therefore it is not a banana

Question 7

What is denying the antecedent? (error)

Answer 7

If p then q
Not p
Therefore not q

All bananas are yellow
This is not a banana
Therefore it is not yellow

Question 8

How good are people at deductive reasoning?

Answer 8

• Modus ponens 97%
• Modus tollens 73%
• Affirming the consequent 63%
• Denying the antecedent 55%

Question 9

What is the reason for failure of reasoning?

Answer 9

Because people know and use logistical rules. Failure of reasoning occurs because people have difficulty combining these rules

Question 10

What was the results in Watson’s selection tasks?

Answer 10

People were able to comprehend the beer example better than the vowels example because the content of the prepositions effects our reasoning process

Question 11

What are pragmatic rules?

Answer 11

Rules we use that are domain specific i.e rules that apply to certain situations
They are activated by the content of the reasoning process

Question 12

What is the permission rule?

Answer 12

That if an action is to be taken, then a precondition is to be satisfied.

Question 13

What is the evidence for pragmatic rules

Answer 13

Envelope problem
– If the letter is sealed, then it has a 5-­‐d stamp on it
– Hong Kong Ss are familiar with the “sealed envelope” scenario
• Cholera problem
– If the form says “Entering” then the other side lists cholera among the list of diseases.

Question 14

What are the characteristics of deductive reasoning?

Answer 14

It is slow and effortful. People make lots of errors, particularly if the scenario is unfamiliar.

Question 15

What are the two systems involved in deductive reasoning?

Answer 15

System 1-
operates quickly and automatically, with little or no effort and no sense of voluntary control.

System 2-
allocates attention to the effortful, mental activities that demand it…and is associated with the subjective experience of agency, choice and control.

Question 16

What is inductive reasoning?

Answer 16

Probabilistic reasoning; e.g.
John majored in accountancy
John now works in an accounting firm
John is an accountant.

Is not deductively valid but inductively strong

Question 17

What is Heuristics?

Answer 17

Rules of thumb; asking an easier question
Tversky & Kahneman-
In inductive reasoning, heuristics is applied and probability rules are ignored.

Question 18

What is availability heuristics?

Answer 18

Estimating the probability on the basis of how easy it is to generate instances
Leads to errors because factors other than frequency affect availability
e.g.
Are there more words in English beginning with K or with K in third position?
Are politicians more likely to be unfaithful?
Are film stars more likely to divorce?

Question 19

What is Representativeness heuristic

Answer 19

Estimating the probability on the basis of similarity

e. g. Jane is medium height, wears nice but comfortable clothes, is single and likes the read 18th century English poetry and plays. Is she more likely to be a shop assistant or an english lecturer
answer: shop assistant because there are more of them.

Question 20

What is a mood heuristic?

Answer 20

No correlation between answers to these questions
- How happy are you these days?
-How many dates did you have in the last month?
High correlation when the question order reversed.
Dating question provides ready answer to more complex question.

Question 21

Examples of target questions vs heuristic questions

Answer 21

Target:
How much would you contribute to save an endangered species.
Heuristic (people might think):
How much emotion do i feel when i think about dying dolphins
Target:
How happy are you with your life these days
Heuristic: What is my mood right now

Question 22

How does availability heuristics affect marriages?

Answer 22

Worsens them-

e. g. How large was your personal contribution to keeping the house tidy in percentages?
- What was your personal contribution to taking the garbage out?

Sum of both partners typically should add up to 100%- but always ends up much higher

Question 23

How is judgement affected in Availability heuristics?

Answer 23

by the number of instances retrieved and by the ease of retrieval.

Question 24

What is the base rate rules?

Answer 24

The probability of something being a member of a class is greater the more class members there are.

Question 25

What is the conjunction rule?

Answer 25

The probability of a proposition cannot be less than the probability of the proposition conjoined with another proposition

e. g. rate the likelihood of each scenario
- Nadal wins
- Nadal loses first set but wins match
- Nadal wins first set but loses match
- nadal loses first set

Question 26

What is the narative fallacy?

Answer 26

Tendency to construct narratives based on flimsy evidence

Question 27

What is the halo effect?

Answer 27

Early information is weighted more heavily
First impressions count
“What you see is all there is”

Question 28

What is hindsight bias?

Answer 28

People have difficulty remembering what they used to believe

Evaluation/post mortem of procedures often based on outcome rather than whether decision was correct or not