Lecture 3 Flashcards
Tunnel vision
You’re looking for information that is in line with your own theory
Bias in sample
Too small size, selective sample
Bias in base rates
The base rate fallacy, also called base rate neglect or base rate bias, is a type of fallacy in which people tend to ignore the base rate (i.e., general prevalence) in favor of the individuating information (i.e., information pertaining only to a specific case).
Example: What is an example of base rate neglect bias?
When asked what the probability is that the cab involved in the hit and run was green, people tend to answer that it is 80%. However, this ignores the base rate information that only 15% of the cabs in the city are green.
Or for joris who is boring and likes to read, you would say he is a librerian, but if you think about how many construction workers we have in the netherlands, he is probably a construction worker.
Law of large numbers
Outcomes become closer to the
expected value with more trials
Gambler’s fallacy
if a particular event, occurs more frequently than normal during the past, it is less likely to happen in the future, even when the events are statistically independent
Regression Effect
Extreme effects will, on average, be less extreme at another point in time.
Effect applies to stable contrext. When there is an unstable context, extreme observation van be indicative of change –? new change or less sick!
Anchoring and adjustment
people give too much weight to the first bit of data for their quantitative estimates.
Anchroing condition 1:
→ Question 1
→ Is the average price of a German car higher or lower
than 20,000 Euros?
□ lower than 20,000 Euros
□ higher than 20,000 Euros
→ Question 2
→ What is the average price of a German car?
Participants estimated 32,000 Euros
condition 2:
→ Question 1
→ Is the average price of a German car higher or lower
than 40,000 Euros?
□ lower than 40,000 Euros
□ higher than 40,000 Euros
→ Question 2
→ What is the average price of a German car?
Participants estimated 37,000 Euros (5,000 Euro more)
conclusion: anchoring helps haha
why does anchoring occur?
- assimilation of quantitative estimates to an available comparison figure (also with numbers that are irrelevant to the decision). In the book there was this wheel of fortune, and participant would answer a higher numbe rif they actuallyhad invested more money in this wheel of fortune.
Explanations of anchoring:
- initial hypothesis = anchoring balue, then people adjust too little
- anchors make different types of information accessible, that are then used in the judgement
Anchoring: accessibility explanation. How can you explain this with the two conditions about the german cars?
→ Condition 1: Is the average price of a German car higher or lower than 20,000 Euros? –> people will start to think more about a volkswagen gold
→ Condition 2: Is the average price of a German car higher or lower than 40,000 Euros? –> people will start to think more about a mercedes for example.
Lexical decision task. conclusions?
- task measure cognitive accessibility
- existing word –> “yes” button (as fast as possible)
- non-existing word –> no button as fast as possible
→ More accessible words are recognised more quickly as being existing words
→ In the 20,000 Euros condition participants recognised cheaper car brands (Opel, Golf) faster
→ Greater chance that this information is retrieved from memory and used to
make an estimate
→ This is why the estimate was lower
→ In the 40,000 Euros condition participants recognised expensive car brands (BMW, Mercedes) faster
→ etc.
What helps with anchoring?
- shaking your head helps a bit
- just leave the negotiation
- experts are still influenced by anchoring
availability heuristic
For example with jaws: People who watched the film Jaws were more likely to overestimate the number
of shark deaths per year than people who had watched another film
- easier to come up with examples of event –> event is estimated to be more probable
→ Subjective ease counts, not number of retrieved examples
→ Examples of assertiveness 12 vs. 6
→ Often leads to good estimates but familiarity and vividness of
information can bias estimates
→ number of people who are members of a student club in Leiden is
overestimated. Shark attacks or lightning deaths are
overestimated.
Risk perception
people will think things like plane crashes and terror attacks are more risky, ust because of the vividly gore. for example.