Judging Probabilites and Frequencies Flashcards
heuristics
simplifying strategies that reduce effort but are prone to bias/error
ecological rationality
apparent biases may be rational responses given the ecology of the human decision maker
effects of “availability” - h
people overestimate rare events and underestimate common events
effect of memory - think things you know more “available”
conjunction fallacy - the letter one
effects of “representativeness - h
judgements of probability are based on assessments of similarity
- base rate neglect
effects of “anchoring” - h
judgements can be anchored by any available information
e.g., a question … more or less than x%
will anchor answers around x
natural frequencies - ev
-probability theory and normalized probability are recent, we are much better at tracking natural frequencies
- natural frequency at which something occurs
misperception of randomness
gambler’s fallacy: betting with/against streaks
hot hand fallacy: a streak is unrepresentative of randomness, therefore infer its not random and predict streak will continue
representativeness can explain these fallacies
misperception of randomness - past experience
- inappropriate generalisation of past experience
- random mechanical outcomes = sampling without replacement
- intentional human performance = positive recency (people recall recent events better)
misperception of randomness - memory constraints
- people can only ever see finite sequences
- people can only hold a short subsection of a sequence in memory
summary - heuristics and ecological validity
- probability judgements often violate probability theory
- one framework posits simplifying strategies that reduce effort at the expense of sometimes introducing bias
- we can also consider judgements in ecological context : one idea that we evolved to process frequencies not probabilities
