Arrovian social choice with psychological thresholds

This paper studies Arrovian preference aggregation rules-the rules satisfying weak Pareto and Arrow's independence of irrelevant alternatives (IIA)-when individual preferences are nontransitive due to the existence of psychological thresholds - a problem of perceptible difference. A new domain replaces the universal domain, and rationality requirements of social preferences, i.e., transitivity, quasi-transitivity, and acyclicity with indifference transitivity, are converted into the corresponding versions respectively. We show that the Arrovian impossibilities, i.e., dictator, oligarchy, and vetoer theorems, still survive in this setting.