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Problem structure and the use of base-rate information from experience.
1Department of Psychology, University of Illinois, Champaign 61820.
Journal of Experimental Psychology. General
|March 1, 1988
Summary
Participants sometimes use base-rate information correctly in medical diagnosis tasks, but often ignore it or use it incorrectly. New models are needed to explain this complex behavior in category classification.
Area of Science:
- Cognitive Psychology
- Decision Making
- Medical Diagnosis
Background:
- Base-rate information, derived from the frequency of occurrence of categories, is crucial for accurate classification.
- Simulated medical decision-making tasks explore how individuals use base-rate information when diagnosing diseases based on symptoms.
Purpose of the Study:
- To investigate the extent to which participants utilize base-rate information in ambiguous medical diagnosis scenarios.
- To compare the predictive capabilities of existing classification models (prototype vs. exemplar-based) regarding base-rate information usage.
Main Methods:
- Five experiments involving simulated medical diagnosis where participants learned disease-symptom relationships.
- Transfer tests presented ambiguous symptom patterns suggesting multiple diseases with varying base rates.
- Analysis of participants' predictions to determine their use of base-rate information.
Main Results:
- Participants demonstrated varied use of base-rate information: appropriate use, ignorance, and inappropriate use (favoring rare diseases).
- The pattern of base-rate information usage was complex and dependent on category structure and test ambiguity.
- Existing classification models failed to predict the observed complex pattern of results.
Conclusions:
- No current categorization model adequately explains the observed human behavior in using base-rate information.
- A novel model integrating property competition and context-sensitive retrieval is proposed to account for these findings.