Conducting psychological experiments in the study of synesthesia

Abstract

Synesthesia is a phenomenon in which sensory inputs trigger additional percepts or cognitive processes. This article outlines a method to conduct psychological experiments with synesthetes. However, synesthesia is a subjective conscious experience possessed by only a small percentage of people, therefore, various difficulties arise when treating synesthesia as a subject of empirical psychological research. Consequently, we introduce definitions of synesthesia and the methods of objective measurement of synesthesia in psychological research proposed in previous studies. We further discuss various individual differences among synesthetes.