Reasoning and Decision Making II

Question 1

two types of reasoning

Answer 1

inductive reasoning
- drawing general conclusions from particular instances

deductive reasoning - drawing conclusions which follow necessarily from the premises, rules of logic

Question 2

propositional

Answer 2

about propositions containing the conditionals: if/and/not/or

Question 3

4 types of inference

Answer 3

modus ponens (if p then q)(It is raining.
Conclude I took the
bus.)

Denial of the
antecedent (if not p then not q) (It is not raining.
Conclude I did not
take the bus.)

affiriming the constant
p(A | B) =/= p(B | A)
(I took the bus.
Conclude it is
raining.)

modus tolens
(I did not take the bus.
Conclude it is not
raining.)

Question 4

study of how often people make 4 inferences

Answer 4

Denial of the
antecedent (DA) - 56%

Affirmation of the
consequent (AC) - 64%

people frequently commit these fallacies

possible explanation: we interpret “if” as “if and only if” (not that convincing)

Question 5

other study of poor reasoning

Answer 5

Wason (1968) Selection Task

D K 3 7

“if there is a d on one side, there is a 3 on the other”

correct answer: D and 7

but only 1 out of 34 people choose D and 7

possible explanation: confirmation bias

Question 6

experiment which shows confirmation bias is not a good explanation

Answer 6

Evans and Lynch (1973) Selection Task

“if S then 9”
“if 2 then not-9” -> participants chose 9, the logically correct answer (not conf bias)

Question 7

card task silly, can work with thematic social rules

Answer 7

Griggs and Cox (1982) Selection Task

“If a person is drinking beer, then the person must be
over 19 years of age”

abstract - 0 out of 40 correct
thematic - 29 out of 40 correct

concluded it is about PREVIOUS EXPERIENCE

Question 8

deontic reasoning

Answer 8

about obligations and permission

Question 9

Support for previous experience hypothesis

Answer 9

cross-cultural studies in which thematic framing only improved performance for participants whose country has a rule of that kind

Question 10

cheater detection/social contract hypothesis

Answer 10

Cosmides (1989) Selection Task

• abstract (25%)
• familiar experience (46%)
• unfamiliar experience about polynesian social rules (21%)
• unfamiliar social contract (cast as member of tribe) (75%)

other experiment: if people are on the hunt for cheats the correct answer will increase

Question 11

problems with cheater detection task

Answer 11

• doesn’t identify mental operations

- people get correct answer

Question 12

relevance/utility hypothesis

Answer 12

Girotto et al. (2001) Selection task

• True descriptive (9%)
• True deontic (62%)
• false descriptive (47%)
• false deontic (15%)

people have been led to the correct P,not-Q selection
by the perceived relevance of those options

Question 13

limitations of selection task

Answer 13

• understanding
  1. think it means if there is a D on TOP
  2. “If there is a D on one side, then there is a 3 on the other and vice-versa”
• doesn’t require any interference
• studies don’t report combinations of answers

Question 14

syllogisms problems

Answer 14

again, there are understanding issues

when being more explicit with language, correct answers rose from 1 in 40 to 27 out of 40

Question 15

atmosphere theory + problem

Answer 15

Begg and Denny (1969)

focused on problems where problems had NO valid solutions

positive premise = more likely to draw positive conclusion
negative
universal
particular

the “atmosphere” (quality and quantity) of the premises shapes beliefs about
the validity of different possible conclusions

issue: fails to explain why/how participants decide whether a syllogism has a valid conclusion

Question 16

mental models framework by Philip Johnson-Laird

Answer 16

1. comprehension- contrust model
2. description - combine models
3. validation - search for alternative models

If a reasoner fails to consider all of the alternative models, he or she is less likely to draw the correct inference

therefore, one-model syllogism easier
multiple-model syllogisms harder

Question 17

(indirect) evidence for mental models account

Answer 17

Copeland and Radvansky (2004)

more mental models = less accuracy, more slowly

participants with higher working memory span were more accurate and faster

Question 18

(more direct) test of mental models account

Answer 18

Newstead, Handley, and Buck (1999)

asked participants to indicate all the possible conclusions they had considered

1. people did not construct more models for multiple-model syllogisms
2. more models =/= higher proportion of correct answers

conclusion: people normally construct just one model

Question 19

how do we construct initial model answer? belief bias

Answer 19

Evans et al. (1983)

valid/invalid + believable/unbelievable

= plausibility increased the judged validity of both valid and invalid arguments.

Question 20

explanations of belief bias

Answer 20

SELECTIVE SCRUTINY HYPOTHESIS

• if conclusion is plausible, people accept it; reasoning occurs more when conclusion is unbelievable
• but no, Evans showed that people reject invalid arguments with plausible conclusions

MISINTERPRETED NECESSITY HYPOTHESIS
-if a conclusion isn’t logically necessary, people use believability more

Question 21

integrating belief and reasoning

Answer 21

Klauer et al. (2000)

• people make mental modes, usually just one
• if conclusion is believable, people try to construct model around this
• if conclusion is unbelievable, they attempt to construct a model which refutes it (alt model)
• when they fail to find one, they are swayed by their belief about the base-rate probability that the conclusion is valid