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.