The metaphor of self/environmental cleanliness in the case of moral concepts: an event-related potential study

The clean metaphor of moral concept refers to the use of a clean experience to represent moral concepts. However, there are different influences on moral judgment between self and environmental cleanliness. The study used the separated Stroop paradigm and the event-related potential (ERP) to explore the metaphorical connection between a clean self/environment and morality. The Experiment 1 found that participants recognised moral words faster after reading environmentally clean sentences than neutral sentences, and the amplitude was more positive in the P300 and N400 time windows. The Experiment 2 found that participants estimated moral words faster after reading self-clean sentences than neutral sentences, and the amplitude was more positive in the P300 and N400 time windows. However, there was no significant difference between self and environmental cleanliness. The findings indicate the psychological reality of the clean metaphor of moral concept and the same effect on environmental and self cleanliness.