3. Judgement
Created @August 21, 2025 1:49 AM
Class PS2021
Judgement: An assessment of the probability of a given event occured based
on incomplete information
Heuristics and Biases Approach
Gigerenzer & Gaissmaier (2011)
Heuristics: Strategies that ignore part of the information, with the goal of
making decisions more quickly, frugally and/or accurately than more complex
methods
Reduce the effort associated with cognitive tasks
Representativeness Heuristics
Representativeness Heuristic: The assumption that an object or individual
belongs to a specified category because it is representative of that category
The Conjunction Fallacy: The mistaken assumption that the probability of a
conjunction for two events is greater than the probability of one of them
Empirical Studies and Evaluation
Point Method Results Conclusion
Tversky and Scenario: Linda 85% Undergraduates Tentori et al. (2013)
Kahneman (1983) is 31 years old, judged the second CF occured
single, statement to be true because of the high
Evidence for The outspoken and despite its statistical perceived
Conjunction Fallacy very bright. unlikelihood probability of the
how people rely on Major in additional
3. Judgement 1
, representativeness philosophy and information
heuristics rather concerned about
than logical social issues. The hypothesis that
reasoning in Linda is a feminist
probabilistic They were then activist is strongly
situations asked to judge supported by her
which of two description (black
statements was shoes and bank
more probable: teller variation)
(1) Linda is a
bank teller, or (2)
Linda is a bank
teller and is
active in the
feminist
movement.
150 medical
practitioners
(Doctors and
specialists)
Mixed-method
approach:
combining
A significant
surveys and
Johnson & percentage of
simulated
Thompson (2021) participants FR: Need for
clinical
demonstrated awareness and
scenarios where
Clinicians rely on this reliance on the training to mitigate
participants were
cognitive shortcut representativeness the risks associated
asked to
when making heuristic, particularly with the
diagnose a set of
diagnostic in ambiguous cases representativeness
patients based
decisions, for atypical heuristic in clinical
on presented
potentially leading to symptoms in practice.
symptoms
misdiagnoses common conditions
Measured
diagnostic
accuracy by
comparing
participants’
responses to the
correct
diagnoses
3. Judgement 2