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Published on: September 19, 2012
Belief digitization: Do we treat uncertainty as probabilities or as bits?
Samuel G B Johnson1, Thomas Merchant2, Frank C Keil3
1School of Management, University of Bath.
People do not use probabilities as degrees of belief, but rather reason digitally, treating uncertain information as either true or false. This "digitization" in human reasoning helps overcome cognitive limits in prediction tasks.
Area of Science:
- Cognitive Psychology
- Decision Science
- Philosophy of Mind
Background:
- Humans are traditionally viewed as Bayesian reasoners, using probabilities to represent degrees of belief.
- The assumption that probabilities directly reflect subjective beliefs is a cornerstone of Bayesian models of cognition.
Purpose of the Study:
- To challenge the assumption that probabilities represent degrees of belief in human reasoning.
- To investigate whether people employ a digital (true/false) approach to uncertain information during inference.
Main Methods:
- Eight experimental studies were conducted.
- Participants learned about two hypotheses with varying plausibility.
- Reasoning processes were analyzed across different manipulations of plausibility and task variations.
Main Results:
- Participants treated uncertain information digitally, categorizing it as strictly true or false for predictive purposes.
- Even when explicitly assigned a positive probability, less-plausible hypotheses were ignored in predictions.
- This digital reasoning pattern persisted across various plausibility cues (simplicity, evidence fit, explicit probabilities).
Conclusions:
- Human reasoning in prediction tasks exhibits digitization, not a continuous probabilistic approach.
- Digitization likely serves to bypass cognitive processing limitations in simulating hypothetical scenarios.
- Findings impact theories in the philosophy of science and cognitive architecture.
Related Concept Videos
Uncertainty: Overview
Propagation of Uncertainty from Random Error
Uncertainty in Measurement: Significant Figures
Propagation of Uncertainty from Systematic Error
Uncertainty in Measurement: Reading Instruments
Uncertainty: Confidence Intervals

