Violations of conjoint independence in binary choices: The equate-to-differentiate intepretation

The studies described in the present paper extend the author's earlier work on testing the “independence condition” for decisions under risk to the “conjoint independence” for multi-attribute decisions. the “equate-to-differentiate” approach, which is proposed as a means by which weak dominance can be made applicable in more general cases in binary choice, is presented to account for the observed violations of independence. Transparency hypothesis concerning violations of the independence axiom is compared with the equate-to-differentiate hypothesis. The findings for various decision tasks favor the equate-to-differentiate explanation. The results support the claim that the violation of the independence should be observed when the equate-to-differentiate strategy is caused to be changed by the experimental conditions applied, but not otherwise.