Predicting self-control capacity - Taking into account working memory capacity, motivation, and heart rate variability.

The present study analyzes possible indicators for state self-control capacity (measured by a Simon task) after demanding executive function tasks as well as for trait self-control (measured by a questionnaire) by focusing on the interplay between control capacity and motivation (measured by demand-related action-state orientation; 154 students; M = 23.55 years; SD = 3.15). As possible control capacity variables, we focused on working memory capacity, based on the integrative theory of self-control, as well as on the baseline cardiac vagal control as a possible physiological index (not a resource itself) indicating control capacity based on the vagal tank theory. The vagal tank theory also focuses on within-subject changes in cardiac vagal control as a possible index of self-control capacity. Therefore, we analyzed among the first 54 participants (M = 24.61 years; SD = 2.67) baseline to post-event changes in cardiac vagal control. Following the integrative theory of self-control, the results indicated that both state and trait self-control capacity are predicted by an interplay of working memory capacity and action-state orientation. Focusing on the vagal tank theory, the results suggest that state self-control capacity can best be detected by the within-subject changes in cardiac vagal control instead of analyzing between-subject differences in cardiac vagal control. However, when focusing on trait self-control, cardiac vagal control might be an indicator, if considered without action state orientation.