Decision Schemes Elicited by the Strategy Method are Impacted by Responders’ Beliefs About Offers in Ultimatum Games

The strategy method is essential for eliciting an individual’s decision scheme in experimental studies; however, it is not clear whether variations in beliefs about which decision node will be reached lead to different decision schemes. In the current study, we aim to directly examine the causal effect of subjects’ expectations for which node will be reached on their decision scheme in the framework of an ultimatum game. Using a logistic quantal response function, we explain why changes in the beliefs of the responders can impact their decision schemes. We then test these theoretical predictions with a set of experiments that use a modified ultimatum game. Combining all three experiments, we find strong and robust evidence that on average, an increase in responders’ beliefs leads to an increase in their acceptance thresholds before they know the offer being made. These findings suggest that the decision schemes elicited by the strategy method need to be treated with more care if the beliefs of responders are changed by the manipulation of other treatment factors