Judgement

Question 1

What are the Heuristics and Biases Approach

Answer 1

• Conjunction fallacy and representativeness heuristic
• Availability
• End anchoring

Question 2

What are the Frequentist Approach

Answer 2

• Base rate neglect
• Improvement with frequency information

Question 3

Tversky & Kahneman (1983)
Conjunction fallacy

Answer 3

• Conjunction fallacy is a type of error where people believe that the chances of two things happening together is greater than the chance of one of those things happening alone
• In Their study 85% made the conjunction fallacy
• They changed the wording of the question for it to be more clear and still 57% made conjunction fallacy

Question 4

Tversky & Kahneman (1983)
Representative heuristic

Answer 4

• Cognitive short cut used when estimating probabilities
  i.e. Linder is more representative of a feminist bank teller than a bank teller alone so people give the second answer

Question 5

Tversky & Kahneman (1983)
Availability heuristic

Answer 5

• The easier it to bring an event to mind, the more likely that event is judged to be
  i.e. asked about causes of death, they said tornado more likely than Asthma even though it is the other way round.
• Due to media coverage and misconceptions of reality and data making it seem more common

Question 5

Coombs & Solvic (1979)

Answer 5

• Newspapers over represent more dramatic causes of death
• People’s judgement of risk related with frequency of media coverage.
  (availability heuristic)

Question 6

Clark & Teasdale (1985)

Answer 6

• Positive and Negative memories recalled more in the appropriate mood in patients with depression
• Thus words and associations change availability

Question 6

Tversky & Kahneman (1974)
End Anchoring

Answer 6

• Negotiation i.e. start higher or lower.
• People’s judgment are influenced by where they start in our thinking

Question 7

Casscells et al (1978)
Base rate neglect

Answer 7

• 50% of Harvard medical students estimated that the probability of the person having the disease is 95%.
• This is base rate neglect as the disease was so rare in the first place and this wasn’t taken into account. Correct answer is 2%.

Question 8

Frequentist Approach

Answer 8

• Claim people have evolved to think in terms of frequencies rather than single event probabilities

Question 9

How should single event probabilities be interpreted

Answer 9

• Some people say probabilities can’t be assigned to single events
• e.g. Pinker (1998), someone says there’s 95% chance they will go to event, they don’t go. Was this then a lie?

Question 10

Cosmides & Tooby (1996)
Frequencies

Answer 10

• They reworded Cascells et al (1978) medical diagnosis problem in terms of frequencies.
• Changed percentages to frequencies
• Changed from single event probability to frequency judgment
• This time, only 4% got it wrong instead of 50%

Question 11

Fiedler (1988)
Frequency version of ‘Linda Problem’

Answer 11

-77% of participants got the correct result with the frequency version of the ‘Linda’ problem

Question 12

Frequentist Approach - Evaluation

Answer 12

• Performance of some tasks improve when problems are phrased in terms of frequencies rather than single event probabilities
• Sometimes tasks can be performed badly as a result of frequentist problems