bias and decision making 2 - heuristics and bias Flashcards
what does it mean that “rationality is bounded”
the world is complex
decisions need to be quick
time is limited
cognitive capacities are limited
reasoning for using heuristics
3 reasons for using heuristics
rationality is bounded
ecological rationality
adaptive heuristics
ecological rationality (ER)
evolutionary perspective for why we use heuristics
rationality = how you should behave in the environment to survive rather than just by norms
correspondence is more important then coherence
- correspondence = with environment, how cognition works in the worlds
- coherence = logic processing
behaviour from the past may fail when the environment changes rapidly
adaptive value
value of an action across evolutionary time
evolution maximises long term expected value
- errors are permissible if there is an overall average benefit
- avoid costly mistakes
- avoid high costs (this includes decision costs)
ecological rationality and the environmental structure
heuristics make assumptions about the environment
about associations and probabilities/risks
heuristics - features and why use them (5)
- strategies in an uncertain world
- make assumptions about world (what keeps us safe)
- allows decision making when unable to use systematic strategies
- don’t attempt to find optimal solution but a good enough one
- can have biases
recognition heuristics
a bias in heuristics
works when:
you have some (not none) knowledge - likelihood of hearing an option correlates with it’s value/importance/size
doesn’t work when:
you know too much or too little
incidence isn’t related to value - can lead to systematic errors
study e.g. which of two cities is bigger
can see how well heuristics work dependent on participants knowledge of the different cities - speed cost to knowing them too well or not at all - found it harder with ones they knew the best
recognition heuristic would cause an error for example with chernoble - aware of it but it is small, may assume it is bigger than it is
feature of a successful heuristic
“fast and frugal”
ignore some info in order to be quick
are biases flaws?
no
heuristics
rules of thumb
strategies to make decisions
favours quick decision making - using less info and not a systematic strategy
3 examples of biases/errors as defined by norms
expected utility theory
laws of logic
laws of probability (e.g. conjunction problem)
deviation from these norms/laws can be seen as an error OR ecological rationality (adaptive)
–> because strategies have evolved and are adaptive so over time they become more successful than not
–> so there are systematic errors in decision making - BUT errors are more beneficial than not
Wasons 2-4-6 task
on the failure to eliminate hypotheses in a conceptual task
task:
find the rule used to create a 3 number sequence e.g. 2 4 6
can propose examples and be told if they fit or break the rule
results:
most people think of a very specific rule (e.g. ascending even numbers) and give a fitting example to test (e.g. 10, 12, 14)
because of:
–> confirmation bias
–> using a positive test strategy (only test it using examples which fit their idea of a rule)
test strategies (2) with Wasons 2-4-6 task
positive tests: seek to verify hypothesis –> but can find it false
negative tests: seek to falsify hypothesis –> but can find it true
which is best –> depends what you believe and how it relates to the truth
what kind of bias is a positive test strategy
confirmation bias
Wasons 2-4-6 –> use of positive test strategies when the rule is general
belief = rule is specific (ascending even numbers)
truth = rule is general (any 3 numbers)
positive test strategy = always confirms belief, therefore belief never improves
