Thinking and Reasoning Flashcards
Heuristics
Strategies that ignore part of the information, making judgements and decisions more quickly, frugally, and/or accurately than more complex methods
Heuristics can be effective but can lead to biases
Attribution substitution
faced with a hard question, you ask an easier one e.g. representativeness, not probability
Natural assessment
automatic and routine
Human rationality
- Essential to judge probability/risk
- Learn from evidence
Are we rational?
- Rational behaviour is defined by rules of probability, economics and logic
- E.g. we are asked to sold a multiplication question, you can either estimate or do long multiplication
- Long multiplication is like rules and programs and algorithms
- Estimation is a shortcut or a rule of thumb or heuristic
- Rules seem more rational than heuristics
Are thinking and reasoning more like rules or heuristics?
Judgement
Process of judging the likelihood of various events using incomplete information
Rules for judgement
- Evaluate judgements by accuracy (what actually happened)
- Evaluate judgements by coherence (obey the rules of probability)
Base-rate neglect
- People tend to ignore the prevalence/base rate/baseline (e.g. 90 out of 100 ppl were salespeople in the quiz)
- Focus on individuating descriptions: stereotypes information
- Proper response: combine prevalence and description
- Follow Baye’s rule
- Example
- Test detects 99% of true cases of a virus, false alarm in 5% of negative cases, 1in 1000 people have the virus
- The probability of virus if you test positive is 2%
- Both lay people and medics find it hard: neglect prevalence
- Crucial to know whether someone is really ill and needs treatment
o Potentially expensive, unpleasant or risky - Medical education specifically teaches this reasoning
- Knowing about causal structure helps: how false positives can arise (e.g. a harmless cyst rather than cancer)
- Motivation helps: not wanting to test positive
- Prespresenting problems differently: natural frequencies
Substitution
- Probabilities are hard
- Substitute something easier
o Related to probabilities, but more natural and automatic - Representativeness
o Decide whether person/object belongs in a category by whether they resemble a stereotype or prototype
The availability bias
- ‘Availability’ related to frequency
o More frequent events are easier to remember - Availability is influenced by other factors
o Systematic errors in judgement - E.g. avoiding flying because of vividness not frequency of crashes
- Can be overridden with conscious thought
- Famous names are more available
- But people tend to say non-famous name is more frequent
o Deliberate thought
The Conjunction Fallacy
- Say there are two events: A and B
- Probability of A occurring (whatever else happens) >= Probability A and B happening together
- Same goes for Probability of B occurring (whatever else happens)
- This is a very common error - cringe
Evaluating decisions
- Evaluate decisions based on consequences
- Consequences alone are not enough
- Probability comes into play also
Expected value
- Value of outcome x probability
- Step 1: calculate expected value (EV)
- Step 2: Choose action with highest EV
- E.g. if it lands on heads you win £200, if it lands on tails you lose £100
EV = V(Outcome) x P(Outcome)
Expected utility theory
- Major theory of modern economics
- For every action, consider each possible outcome
- EU (outcome) = utility (outcome) x p (outcome)
- Choose action with highest utility
- A rational decision maker maximises their utility
- Implies a set of rules all of which people violate
Loss aversion
- We are more sensitive to loss than gain
- Losses feel worse than gain feels
Risk preferences
- People treat gains and losses differently
o Whether outcomes are certain or variable - Most are risk averse with gains
o Prefer certainty even if you’ll probably win less that way - Most are risk-seeking with losses
o Prefer a risky loss even if you’ll probably lose more that way
Implications
- Liking and disliking are subjective
- What if I could make the same event seem like a loss or a gain
Tricked by wording
- Effect is robust for risky choice framing and attribute framing (e.g. 95% fat free)
- Effects can be reduced:
o With clearer phrasing
o When asked to justify decisions
o When people are experts or highly involved
Deductive reasoning
- Governed by formal logic
- Set of rules for valid reasoning
Inductive reasoning
Obs 1. Met train is late
Obs 2-200. Met train is late
Therefore met trains are late
To assess argument
- Identify the propositions (statements that could be true or false)
- Identify the pattern of reasoning (symbolise the argument)
- Does it match a rule?
Modus ponens
if P, then Q. P. Therefore Q.
Dual process theories
- Sometimes we violate rules other times we follow them
- Some stable differences between people
- Not just intelligence
o Performance unrelated to intelligence on many tasks - Thinking fast and thinking slow
Dual process theories
Type 1
Type 2
Type 1
intutive
automatic
immediate
easy
heuristic
Type 2
analylitcal
conscious
slow
demanding
rule-governed