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An encounter frequency account of how experience affects likelihood estimation
Natalie A Obrecht1, Gretchen B Chapman, Rochel Gelman
1Psychology Department, Rutgers University, Piscataway, New Jersey 08854-8020, USA. natalie@ruccs.rutgers.edu
Memory & Cognition
|June 3, 2009
Summary
People often prefer individual stories over statistics. This study shows that how frequently information is encountered, not sample size, influences judgment, impacting event frequency estimates.
Area of Science:
- Cognitive Psychology
- Decision Making
- Information Processing
Background:
- Individuals frequently rely on anecdotal evidence over statistical data.
- Information is acquired either piece-by-piece (individual) or as a summary (statistical).
Purpose of the Study:
- To investigate if encounter frequency influences data weighting.
- To determine how serial versus summarized presentation of individual cases affects judgments.
Main Methods:
- Two experiments presented participants with statistical and individual case data.
- Individual cases were either summarized or presented serially.
- A third study examined data sample treatment.
Main Results:
- Event frequency estimates were higher when individual cases were presented serially compared to summarized.
- Participants treated each data sample as an instance, irrespective of sample size.
Conclusions:
- Information weighting is influenced by encounter frequency, not solely by sample size.
- Serial presentation enhances the perceived frequency of individual data points.
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