Related Experiment Video
Updated: Jul 18, 2026
09:13
A Real-world What-Where-When Memory Test
Published on: May 16, 2017
Typical versus atypical unpacking and superadditive probability judgment
Steven Sloman1, Yuval Rottenstreich, Edward Wisniewski
1Cognitive and Linguistic Sciences, Brown University, Providence, RI 02912, USA. steven_sloman@brown.edu
Summary
Unpacking event descriptions can decrease probability judgments, especially with atypical instances. This finding challenges support theory, suggesting category interpretation influences probability assessments.
Area of Science:
- Cognitive Psychology
- Decision Science
- Behavioral Economics
Background:
- Support theory predicts unpacking increases probability judgments.
- Category descriptions may be interpreted narrowly based on typical instances.
Purpose of the Study:
- To investigate how unpacking event descriptions affects probability judgments.
- To test predictions derived from category typicality against support theory.
Main Methods:
- Participants provided probability judgments for packed vs. unpacked event descriptions.
- The typicality of unpacked instances was systematically varied.
Main Results:
- Unpacking typical instances showed no effect on probability judgments (additivity).
- Unpacking atypical instances led to decreased probability judgments (superadditivity).
Conclusions:
- Findings contradict support theory's general prediction of increased judged probabilities upon unpacking.
- The typicality of instances significantly moderates the effect of unpacking on probability judgments.
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