Self-Other Discrimination in Active and Passive Movements

A previous study by Wen et al (2023) and (2024). suggested that the processes driving self-other discrimination differ depending on the self-movement component within the object (level of control). This study reported that when the level of control is high, the self-other distinction is based on prediction errors, whereas when the level of control is low, the distinction is triggered by exploring regularities with the object through self-movements. This exploration of regularities is contributed to by one's own intended movements (active movements). In tasks involving the search for a target congruent with self-motion among multiple visual stimuli, it has been reported that reaction times are significantly longer when the arm is passively moved compared to when it is actively moved (Salomon et al., 2013). These findings suggest that self-other distinction processing switches between prediction error-based matching and regularity exploration, depending on the level of control, and that its accuracy may be modulated by the nature of the movement intention (active versus passive). However, the difference between distinction accuracy and the underlying cognitive processes remains unclear. The present study investigates the effects of the level of control and motor intention on self-other distinction and whether differences exist in cognitive processes through two experiments. In the first experiment, the level of control of one of two visual stimuli is fixed at 0%, while the other is fixed at either 50%, 60%, or 70%. Participants are asked to report which one felt most like their own movements after either actively moving their hand or having it moved passively, and to rate their confidence in that judgement. This design enables the distinction and comparison of participants' innate sensitivity to self-other discrimination and their cognitive processes. In the second experiment, the level of control is adjusted using a staircase to align participants’ distinction accuracy between movement conditions (active vs. passive), enabling comparison of cognitive processes across both conditions. Based on these experiments and analyses, we aim to elucidate the mechanism of self-other discrimination modulated by the level of control and motor intention. Refereces: Wen, W., Charles, L., & Haggard, P. (2023). Metacognition and sense of agency. Cognition, 241(105622), 105622. Wen, W., Mei, J., Aktas, H., Chang, A. Y.-C., Suzuishi, Y., & Kasahara, S. (2024). Control over self and others’ face: exploitation and exploration. Scientific Reports, 14(1), 15473. Salomon, R., Lim, M., Kannape, O., Llobera, J., & Blanke, O. (2013). “Self pop-out”: agency enhances self-recognition in visual search. Experimental Brain Research. Experimentelle Hirnforschung. Experimentation Cerebrale, 228(2), 173–181.