# Multiple Strategies in Conjunction and Disjunction Judgments: Most People are Normative Part of the Time

- James Tripp,
*University of Warwick, Coventry, West Midlands, UK*
- Adam Sanborn,
*University of Warwick, Coventry*
- Neil Stewart,
*University of Warwick*
- Takao Noguchi,
*University College London*

## Abstract

Do people use a single strategy or sample from multiple strategies
when estimating the conjunction and disjunction of two independent events? Here
we address this tension directly by comparing individual level Bayesian
simulations of multi and single strategy models using data from a frequency
estimation experiment. Participants were shown two statements describing
attributes and asked to estimate how many people had either one attribute,
conjunction, or disjunction of attributes. In our Bayesian simulations we compare
models in which participants either adopt a single strategy or sample from a set
of strategies when forming estimates of both conjunctions and disjunctions. We
compared every permutation of models in which a participant is responding based
on a single component, a weighted average of the two events, probability theory,
or combination of strategies. Our findings show that people sample from multiple
strategies and are sampling from the normative strategy some of the time.

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