The Influence of Freedom and Choice in Action Selection and the Valence of Action-outcomes on the Sense of Agency

Sense of agency (SoA) refers to the subjective experience that one is the author of their actions and the ensuing outcomes of these actions. Previous research have suggested that both sensorimotor processes and high level inferences can contribute to the SoA. In five experiments, the present thesis examined the effects of action selection processes and the valence of action-outcomes on the SoA. The majority of these experiments measured the SoA by obtaining both subjective feeling of control (FoC) judgments over the action-outcomes, and assessing the size of intentional binding. Intentional binding refers to the perceived temporal attraction between actions and their outcomes, and has been suggested as an implicit measure of the SoA. Experiment 1 manipulated the number of action alternatives as low, medium, and high and examined the effect of choice-level on intentional binding. The results showed that binding was strongest when participants had the maximum number of alternatives, intermediate when they had medium choice-level, and lowest when they had no choice. Experiment 2 recruited western and non-western participants and focused on the impact of pleasantness of action outcomes on both intentional binding and FoC judgment. The results revealed that both western and non-western groups showed greater FoC ratings for the pleasant compared to unpleasant outcomes. Moreover, for the western group only, binding was stronger for pleasant compared to unpleasant outcomes. In Experiment 3, participants performed freely selected and instructed actions, which could produce pleasant or unpleasant outcomes. The results revealed stronger binding and higher FoC ratings in the free- compared to instructed-choice condition. Additionally, FoC ratings were higher for the pleasant compared to the unpleasant outcomes. Similarly, Experiment 4 varied the choice-level between one (instructed), two, three, and four alternatives while the outcome of any choice could be pleasant or unpleasant. The results showed that binding was stronger in the four-choice condition compared to one-, two-, and three-choice conditions, while FoC ratings were systematically increased as the choice-level varied from one to four, and were higher for pleasant compared to unpleasant outcomes. In Experiment 5, participants were primed with either action or neutral images and performed either free or instructed actions. Free actions could be preceded by either neutral (neutral-free) or action primes (primed-free), and instructed actions indicated performing either prime-compatible or prime-incompatible actions. The findings showed that both binding and FoC ratings indicated stronger SoA in the neutral-free condition compared to all remaining modes of action selection. Moreover, these two measures of the SoA were significantly correlated. The overall results from these studies indicate that situational factors surrounding actions determine the contribution of predictive, prospective, and retrospective mechanisms to intentional binding and subjective judgments of agency. Among these factors, the present thesis highlights that one’s freedom in action selection and the availability of various action alternatives can strongly influence the SoA