reasoning

Question 1

reasoning

Answer 1

involves using knowledge within systems of formal logic

you have some knowledge of the world and how things are causally linked that allow you to come to some conclusion

2 types of reasoning
* inductive reasoning
* deductive reasoning

Question 2

inductive reasoning

Answer 2

specific facts = draw general conclusions

going from specific facts and drawing general conclusions from them
* primary ways to make predictions and generate knowledge about the world

Plato, Aristolte, Wundt, Skinner were all mortal….therefore all humans must be mortal

Question 3

deductive reasoning

Answer 3

general claims - asks what follows from these premises (go to more specific claims from there)

All humans are mortal. James is a human. Therefore James is normal

more research

which type of reasoning can you be more certain of
* has to do with how you think about things

Question 4

syllogisms

Answer 4

basic reasoning puzzle – given premises, does the conclusion follow?
– uses deductive reasoning

example:
* all men are mortal
* socrates is a man
* therefore, socrates is mortal

Question 5

syllogisms that don’t follow logically

Answer 5

If spot is a lizard
spot is not a lizard
therefore, spot is not an animal

if you clean your room, I will give you $10
you do not clean up your room
therefore, I do not give you $10

Question 6

syllogisms that follow logically

Answer 6

no democrats are conservatives
some Americans are conservatives
therefore some Americans are not democrats

no healthy things are cheap
some vitamin pills are cheap
therefore, some vitamin pills are not healthy things

Question 7

why are syllogisms hard

Answer 7

belief bias: the tendency to think that a syllogism is valid if its conclusions are believable

true and valid are not equivalent

true: the way the world as we know it works
valid: logically follows from premises

we are bias to see what we believe to be true to be logically valid as well

syllogisms do not reflect how people view the world

most of the time we use knowledge about the world and if the conclusion is believable, we say its logical even if it doesn’t formally make sense

we tend to confuse something that follows logically vs something that is valid

what makes it difficult?
* quantifiers
* negation

Question 8

quantifiers make syllogisms hard

Answer 8

the word “some”

none of the athletes is a student
some of the clerks are students
therefore

valid inference: some of the clerks are not athletes

Question 9

negation makes syllogisms harder

Answer 9

a refusal or denial of something

if it is friday night, then Bill is drunk.
It is Friday night
therefore Bill is Drunk

if it is Friday night, then Bill is drunk
Bill is not drunk
Therefore it is not Friday night

(doesn’t say anything about if he is not drunk)

Question 10

syllogisms summary

Answer 10

• better at reasoning if we do not use quantifiers and negation
• better when consistent with beliefs

Question 11

propositional reasoning

Answer 11

an assertion (or proposition) that is tested

Today is Monday
– is it Thursday?
– respond if true (yes or no)

have a statement and you answer if it’s true or not

Question 12

wason card selection task

Answer 12

making syllogisms more complicated

rule: if a card has an “A” on one side then it has a “4” on the other side

A B 4 7

– to test this, cards A and 7 must be turned over

A only 33% turned over
A and 4 45% turned over
A and 7 4% turned over

Question 13

propositional reasoning – Modus Ponens

Answer 13

Latin - mode that affirms

If P, then Q
P.
Therefore Q

testing A

Question 14

propositional reasoning – Modus Tollens

Answer 14

latin: the way in which this is denied (finding a case in which this rule is broken)

• you need to find an example where Q is false

If P, then Q.
Q is false (or not Q)
Therefore P is false (or not P)

testing the 7 because if there is an A behind, you have an example card that disproves the rule

people get more hung up on this part

Question 15

why is the Wason Card selection task so difficult?

Answer 15

falsification principle: to test a rule, you must look for situations that falsify the rule

tendency to try to affirm the rule each time

training in logic doesn’t help: researchers found little improvements for college students who had just taken a logic course

experience with situations help

Question 16

wason card selection vs experience

Answer 16

if a person is drinking beer, then that person is over 19

found that if you put the same problem in an experience than you do fine
* using real world knowledge

to test this rule – should pick the drinking beer option and the NOT over 19 option to see if the rule applies

seeing if the not over 19 are drinking beer to negate the rule

Question 17

confirmation bias

Answer 17

the tendency to only look for information that supports your existing beliefs

Wason 246 task
* find a rule that generates correct 3 number sequence
* 2-4-6 is a correct sequence
* search for the rule by testing as many sequences as you want

the rule is that the sequence has to increase
* people guess with similar patterns
* you figure it out by suggesting numbers going down

rarer for people to come up with sequences that breaks the rule, which makes it harder to determine the rule

Question 18

the 2-4-6 task

Answer 18

Twenty
* tested a variation of the 246 task
* participants were instructed to find two rules rather than just one

rules:
* DAX: 3 accendng numbers (Wason’s original rule)
* MED: any other triple (does not obey the DAX rule)

each time a triplet of numbers was suggested by participants, they were told if it was either a DAX or a MED triplet

people were much better at discoverng the DAX rule than in Wason’s original study
– shows how the way a task is presented affects how it is tackled

DAX is providing sequences that breaks rule, people are less likely to fall into the confirmation bias
** harder for people to come up with example that disprove rather than proving a problem

Question 19

scientific reasoning and confirmation bias

Answer 19

confirmation bias can influence science

hypothesis testing:
* generate an explanation for some phenomenon
* design experiment to test it

confirmation bias:
* if results confirm hypothesis more likely to believe it is true

how do we fight against this tendency?
* falsification principle: look for situations that falsify the hypothesis

scientists are more likely to come up with stuff to confirm a hypothesis rather than one that negates it

Question 20

reasoning – implications

Answer 20

reasoning is not just abstract logic

experience affects reasoning

assumptions we make are critical
* our believes and experiences at how the world works
* in effect they add premises

general knowledge of the world will affect how you judge a conclusion