Sense of agency based on the numerical magnitude of action-outcomes

Sense of agency (SoA) refers to the sensation that one’s actions cause changes in the environment. Studies have shown that SoA is strengthened with the speed of motion stimuli appearing as a result of pressing keys, suggesting that SoA depends on the extent of action outcomes. This study examined whether the numerical magnitude of action outcomes would also affect SoA. Experiment 1 was conducted online, where participants pressed keys and the dots were presented. Subsequently, the participants rated their SoA regarding the keypress on a 10-point scale. The results indicated that SoA was rated higher with a greater number of dots. Experiment 2 replicated this phenomenon in the laboratory and obtained similar results. Experiment 3 investigated whether a similar effect could be observed using the numerical values of a digit instead of the number of dots. The results showed that SoA was rated higher as the numerical value of the digit presented after pressing the keys increased. These results suggest that the numerical magnitude contributes to the formation of the SoA.