thinking 2 Flashcards
what are normative answers to problems?
the most mathematically correct way of solving a problem, based on probability
is human reasoning normative?
often biased
people use heuristics (cognitive short cuts) to answer questions
what is the representitiveness heuristic?
the likelihood of an event is evaluated by the degree to which it is representative of the major characteristics of the process/population from which it originates
assume that representative/typical members of a category are encountered more frequently
how is the representative heuristic demonstrated experimentally? (Kahneman and Tversky)
participants had to judge people from a brief character description
the box contained descriptions of lawyers and engineers
could decide the job based on a person’s description
ignored the base rate that people are more likely to be an engineer
what is the conjuction fallacy?
the co-occurence of two events cannot be more likely than the probability of either event alone eg) feminist bank teller not more likely than bank teller
occurs as specific scenarios appear more likely than general ones, as they are more representative of how we imagine them
what is the gambler’s fallacy?
the mistaken belief that random events, eg) tosses of a coin, are influenced by past events
what is the availability heuristic?
decision makers assess the probability of an event by the ease of which instances of the occurence can be bought to mind
what supports the idea of the availability heuristic?
participants judged lethal events- overestimated some and underestimated others, due to the media coverage of these events
although disease kills more people than accidents, the media reports more people dying by accidents than disease
individuals tend to overestimate their contribution to a group task- this varies depending on how the question
asked which is more frequent: ‘word has K as the first letter’ or ‘words with K as the third letter’- majority answered incorrectly saying the first option as our mental lexicon is organised by spelling
what is base rate neglect (Tversky and Kahneman)?
cab involved in hit and run accident
85% green cabs and 15% blue cabs
witness said it was blue
correctly identifies colour 80% of time, and fails 20% of the time
many people falsely said the taxi is more likely to be blue than green
suggested to be due to the representativeness heuristic= focus on witness’ accuracy and neglect base rate of cabs in the city
what happened in base rate neglect: medical diagnosis problem?
Casscells asked medical students question:
If a test to detect disease of prevalence 1/1000 has a false positive rate of 5%, what is the chance the person actually has the disease?
45% responded 95% and ignored the base rate
when asked using frequencies rather than probabilities, more people chose the correct answer
