Moral Neuroscience Mechanisms Underlying Daily Moral Decision-Making: Evidence from ERPs

Abstract

Morality has been one of the key elements of moral judgment research, but due to the complexity of moral mechanism, individuals are susceptible to the influence of social desirability in moral decision making, resulting in low validity of questionnaire and interview method results. With the development of cognitive neuroscience techniques, it is possible to explore the internal neural mechanisms of individuals in moral decision-making through neuroscience techniques. As a result, the mechanisms of moral neural processing have recently received much attention. This study intends to explore the internal mechanisms of moral neural processing through a neuroscientific research paradigm. This experiment was conducted with 23 student subjects from a university, and the experimental design was a one-factor experimental design with moral decision types: immoral vocabulary, moral vocabulary, and non-moral vocabulary. Analyses were conducted using a two-factor repeated measures ANOVA for moral type 3 (immoral vocabulary vs. moral vocabulary vs. non-moral vocabulary) x 4 brain region location (left forebrain vs. right forebrain vs. left hindbrain vs. right hindbrain). An event-related potentiation technique was used to respond to moral and immoral words and to explore the electrophysiological information in the processing of moral-related words. The results showed that N2 wave amplitude for moral decision type3 (moral vs. immoral vs. non-moral) x EEG location4 (left forebrain vs. right forebrain vs. left hindbrain vs. right hindbrain) two-factor repeated measures ANOVA found a significant F(6, 108) = 6.824, p < .000, 2 for the interaction between moral decision type and EEG location =.414. As the interaction was significant therefore the simple effects were analysed and found that the simple effect of moral decision type and EEG location was significant at p<0.000, EEG location at the moral level was significant F(3, 54) = 16.00, p<0.001, EEG location at the immoral level was significant F(3, 54) = 16.00, p<0.001 and EEG location at the immoral level was significant F(3, 54)=19.00, P<0.000. A two-factor repeated measures ANOVA on P3 latency for moral decision type3 (moral vs. immoral vs. non-moral) x EEG location4 (left forebrain vs. right forebrain vs. left hindbrain vs. right hindbrain) found a significant F(6, 108) = 4.328, p < 0.003, interaction between moral decision type and EEG location. Moral decision type interacted significantly with EEG location F(6, 108) = 8.900, p < 0.000. Since the interaction was significant, simple effects were analyzed, controlling for the EEG location factor, moral decisions differed significantly F(3, 54) = 14.69, p < 0.000, unethical decisions differed significantly F(3, 54) = 7.62, p < 0.000, and unethical decisions differed significantly F(3, 54) = 11.62, p < 0.000. The neural time processing of moral decision-making processing and unethical decision-making processing are more consistent. Moral decision-making activates more brain areas; Moral decision-making is relatively more complicated. The processing process of moral decision-making is consistent with that of unethical decision-making. Moral decision-making activates more EEG components.