The influence of voluntary action and social distance on sense of agency: Evidence from behavioral and ERPs study

Sense of agency refers to the subjective experience of controlling one's actions and, through them, external events, which is the core element that makes individuals responsible for their behavior to foster social cohesion. Recent studies have revealed that people potentially experience reduced sense of agency for harming others by claiming that they were obeying orders. However, little is known about the cognitive neural mechanism behind the reduced sense of agency when individuals are forced to inflict physical harm on others. We adopted a temporal estimation task to investigate the internal mechanism of voluntary action on the sense of agency and the moderating effect of social distance, as measured by event-related potentials (ERPs). In Experiment 1, participants were asked to trade monetary gains for themselves off against painful electric stimuli experienced by friends or strangers, subjectively estimated the perceptual temporal interval between keypress actions (i.e., free, or coercive actions) and consequent neutral outcomes, and rated the feeling of control and responsibility. Experiment 2 further investigated the cognitive neurobiological mechanisms of the interaction between voluntary action and social distance on the sense of agency using event-related potential (ERP) technology and attempted to examine the robustness of explicit sense of agency. Experiment 1 found that under the coercive condition, the time interval estimation for harming friends was shorter than for harming strangers, indicating a stronger implicit sense of agency. Regarding the explicit sense of agency, our study only found that participants in the free condition reported higher feeling of control and responsibility compared to those in the coercive condition. In Experiment 2, these results indicated that when participants obeyed commands to harm friends, the P3 was larger than when they obeyed commands to harm strangers. More importantly, the N1 was more negative in response to the auditory tones when participants obeyed commands to harm friends than when they obeyed commands to harm strangers. However, regarding the explicit sense of agency, our study only found that participants in the free condition reported higher feeling of control and responsibility than those in the coercive condition, which were not influenced by the social distance. Additionally, there was a significant correlation between the ratings of feeling of control and the decision-induced N2. These results indicate that social distance moderates the implicit sense of agency in the face of serious unethical outcomes, while participants' feeling of control and responsibility were not affected by social distance due to self-serving bias. When obeying orders, individuals consciously exhibit moral disengagement. The present study has demonstrated that implicit and explicit sense of agency have different processing mechanisms, which broadens the previous insight into understanding the sense of agency. We discuss the implications of utilizing free choice and closing the social distance with others as significant strategies for those experiencing the abnormal sense of agency.