# A Quantum Probability Explanation for Violations of Symmetry in Similarity Judgments

- Emmanuel Pothos,
*Swansea University*
- Jerome Busemeyer,
*Indiana University*

## Abstract

A model of similarity is presented which is based on Quantum
Probability (QP) theory. The model is applied to the case of violations of
symmetry in similarity judgments, as demonstrated by Tversky (1977). The QP
similarity model can predict such violations, on the basis of the same underlying
intuitions as Tversky (1977). Moreover, we discuss how the model can be extended
to account for violations of the triangle inequality and also the empirical
findings in relation to Tversky’s diagnosticity principle.

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