A Study On Event-related Potential About Moral Judgment And Disgust Judgment

It is generally found by observations in the daily life and investigation from survey researches, that people always associate ethical violations with aversion. As one of human basic emotions, disgust helps people to avoid contacting with germs which likely to cause physical illness. The rejecting functions of disgust may be expanded to social field to help people to stay away from the violation of social norms and harm to others. In human evolution and individual development, abstract, high-level moral disgust may evolve from the specific, low-level physiological aversion. But so far, there is still heated argument on whether moral disgust is a kind of physiological aversion essentially, and whether disgust emotion plays a decisive role in moral judgment. The present study proposed that finding out the time course of moral judgment and disgust judgment is a very effective perspective to explore this question.The present study used event-related potentials (ERP) to investigate the temporal order between moral judgment and disgust. We fabricated224statements describing social events, and invited59college students to evaluate the validity of the experimental material. In the formal experiment, a task combining a go/no-go decision and a left/right-hand response was used. That is, the participants were required to press button with left/right hand or not, according to their moral judgment and feeling disgust at the same time, with equal stress on the speed and accuracy. The physiological index, lateralized readiness potential (LRP) was employed to mark the moments at which disgust or moral judgment firstly arises to prepare for manual response.Results showed that LRP existed since690ms on the Go condition of task2.Meanwhile, there was early LRP with latency860ms which returned to baseline after1030ms on the No-Go condition of task2.However, LRP did not occur from beginning to end on No-Go condition of task1.LRP existing on NO-GO condition of task2suggested that the brain make the choices of pressing with left/right hand firstly, that is making moral judgments firstly, and then withheld the responses according to the results of disgust judgments. No LRP existing in task1illustrated that the above results are not caused by the inherent response pattern that making the choice of left/right hand takes precedence over the choice of pressing the key or not.Under the requirement of fast to reaction the brain progress moral information is prevailing in time course than disgust. The experimental results do not support the argument that the moral disgust originated in the original aversion, but it proved that there is a logical possibility that the violations of moral cause aversion. Social intuition model of moral judgment theory and the theory of "moral device"could find empirical basis from this experimental results.