Abstract
Missing an opportunity that could have been better by a narrow margin is more regrettable than missing it by a wide margin because it is easier to access the counterfactual. In addition, uncertain counterfactuals are less available and thus the uncertainty reduces the feelings of regret. This study compared the effects of the narrowness and the uncertainty of counterfactual. Using missed profit vignettes, we set four conditions: the wide margin condition, the narrow margin condition, the uncertain condition, and the control condition. The experiment was run on the web and 69 university students answered the strength of their regret on seven-point scale. As a result, regret was the strongest in the narrow margin condition and that of the uncertainty condition was not between those of the narrow margin condition and the wide margin condition. We confirmed that the narrowness is not the only factor affecting the feeling of regret.
