reasoning Flashcards
what is reasoning
to infer a conclusion from some initial information or premise
what is inductive reasoning
conclusions are probably (but not nescessarily) true
-about probabilities not definites
-draws probabilities with incomplete info
example of inductive reasoning
most snowstorms come from the north. its starting to snow so must be from the north
what are heuristics
mental shortcuts that can reduce cog load
what do people rely on when they dont follow the probability rules
heuristics
what can heuristics lead to
errors and stereotyping
what is the availability heuristic
-a representation that is immediately available to us
-generally works well in a range of contexts BUT events more easily remembered are judged to be more probable (tversky and khanemann 1974)
availability heuristic and the media example
what is more common: traffic accidents or stomach cancer?
-people estimate traffic accidents as more common
-actually stomach cancer is 4x more common
why do people come to the wrong assumptions (heuristics and the media)
the media report 137 traffic fatalities for every 1 stomach cancer death
what is representativeness heuristic
conjunction fallacy: the wrong assumption that 2 specific conditions are more probable than one condition
example of conjunction fallacy
khanemann and tversky 1983
-pp asked to rank order of outcomes from most to least likely
1. andy murray will win match
2. murray will lose first set
3. murray will lose first set but win match
4. murray will win first set but lose match
-pp rated bottom 2 (with 2 specific cond) as more likely than the top 2
what is hypothesis testing
-example of inductive reasoning
-based on limited data
-gains evidence to confirm the hypoth is correct (as done in most studies)
-gains evidence to falsify the hypoth
what is confirmation bias
seeking to confirm a hypoth but failing to attempt to disprove it e.g boiling water 1000 times and finding it always boils at 100.c
cowley and brynes 2005 study
-pp more likely to attempt to falsify a hypoth if it is generated by someone else
-25% abandoned own hypoth
-62% abandoned other’s hypoth
-provides insight into inductive reasoning
wason’s 246 task
-pp given 3 numbers and asked to provide 3 numbers to test a theory
-given feedback and asked what the pattern is
-28% of pp failed to guess the pattern correctly bc they failed to attempt to disprove their hypothesis
e.g if pp keep testing the wrong pattern ‘numbers that go up in 2s’ they reach the wrong pattern as it’s actually ‘any 3 numbers in increasing order’ - if pp had attempted to falsify this would have helped
when might confirmation testing be more appropriate than falsification
drug trials
hypothesis testing in the real world research
Fugelsang et al 2004
-looked at results from 417 science papers
-only 12% modified theories based on discrepant results
-61% changed theory if discrepant results were replicated
what is deductive reasoning
-draws definite conclusions based on formal logic
-2 types: syllogistic and conditional reasoning
what is syllogistic reasoning
-syllogism consists of 2 statements followed by a conclusion
e.g all birds are animals. all animals eat food. therefore all birds eat food
-not very common in real life
what is conditional reasoning
-uses logical operators (if and or)
-more common day to day
e.g IF a third is required to pass swansea psych degree AND amy is graduating from swansea uni THEN we can conclude amy got a 3rd or higher
wason’s selection task
-if a card has a vowel on one side then it has an even number on the other side
-which cards should you turn to determine if this is true or false
-confirmation is not enough, falsification also needed
-answer is to turn over a card with a vowel and card with an odd number
-only 4% got this right
how does deductive reasoning work
-begins with general and makes assumptions about specific situations
e.g all of our snow storms come from the north. its starting to snow therefore, the storm is coming from the north
goel and dolan 2004 study of deductive < inductive and vice versa
-deductive > inductive: L inferior frontal gyrus
-inductive > deductive: L dorsolateral prefrontal gyrus
-deduction (definite): all animals with 32 teeth are cats. no cats are dogs. no dogs have 32 teeth
-inductive (probable): cats have 32 teeth. lions have 32 teeth. all felines have 32 teeth
waltz et al 1999 study into PFC
-easy: sam is taller than nate, nate is taller than roger
-hard: beth is taller than tina, amy is taller than beth
-patients with damage to PFC do fine on easy tasks but badly on harder tasks
-support found by Raven’s matrices task
Bechara et al 1999 lowa gambling task
-pp choose card from deck
-each card has a reward and sometimes a loss
-pp must discover which decks are advantageous
-payoff structure unknown to pp
-neurotypicals learnt quickly to avoid bad decks
-pp with damage to PFC performed poorly and stayed with bad decks (larger reward but also larger losses)
-galvanic skin response measured to check arousal
-neurotypicals showed greater arousal in anticipation
-patients with damage to PFC showed less and no difference between anticipating rewards and losses
Domansio et al 1996 somatic marker hypothesis study to explain bechara study
-we move away from bad decks bs emotional system warns us about potential losses
-suggests emotional system is having direct effect/ causal influence on our decision making
