Week 7 Lecture 6 - reasoning and decision making Flashcards
What are heuristics?
Simplifying strategies that reduce effort but are prone to bias/error
What is ecological rationality?
Apparent biases may be rational responses given then ecology of the human decision making
What are 2 explanation for why humans are bad at making probability judgements?
- heuristics
- ecological rationality
What are the 2 systems involved in your decision making?
- fast intuitive one (used most)
- slow rational one
What are 3 examples of heuristics?
- availability
- representativeness
- anchoring
What is the availability heuristic?
If you can bring to mind something e.g., an event, it is likely that it occur frequently, if you cannot it is likely not a common occurrence
How can availability heuristics bring in error?
may be more likely to remember shocking or frightening events leading you to think they occur often e.g., shark attacks
What did a study find when asking people to estimate causes of death? Which heuristic is this consistent with?
people:
- overestimate rare events
- underestimate common events
consistent with availability heuristics
What did a study investigating the effect of memory on availability find?
- it is easier to remember famous names than less famous names
- ppts judged that the gender with famous names was more frequent (as it is easier to bring the famous names to mind)
What can the availability heuristic lead to?
The conjunction fallacy
What is the conjunction fallacy?
A common reasoning error in which we believe that when two events are happening in conjunction one is more probable than the other
This is because people will find one easier to bring to mind than the other so think it occur more often
Given an example of a conjunction fallacy
“In 4 pages of a novel, how many words would you expect to find that have the form “___ing” and “_____n_”
What is the representativeness heuristic?
judgements of probability are based on assessments of similarity
What is base rate neglect an example of?
the representativeness heuristic
What is base rate neglect?
the tendency to underweight base rate or prior information compared with current, individuating information when estimating probability of uncertain events
What is the anchoring heuristic?
the assimilation of a numeric estimate towards another, anchor value
What is “anchor-and-adjust”?
we use the anchor as an initial estimate of the target value and adjust from that starting point in the right direction; because the adjustment is effortful, we often adjust insufficiently and so our judgment is biased towards the anchor value
What is a potential issue with the anchoring heuisitc?
Incentive, warnings and cognitive capacity have little effect on accuracy
Many other mechanism produce the same effect
What are 2 formats of ecological rationality?
- natural frequencies
- misperception of randomness
What is the inverse fallacy?
the mistaken belief that the probability of the data given the null hypothesis, P(D|H0), is equivalent to the probability of the null hypothesis given the data, P(H0|D).
What does Bayes theorem tell us about probabilties?
Bayes’ theorem tells us how we should update our beliefs to give the posterior probability that H is true, given our prior belief and the new data
What are natural frequencies?
A joint frequency of two events, such as the number of patients with disease and who have a positive test result, and is an alternative to presenting the same information in conditional probabilities
presenting information with rational numbers rather than percentages is easier to understand
Are people good at judging when something is random or not?
no
What is the Gambler’s Fallacy consistent with?
Misconceptions of randomness