From simple everyday choices to life-altering decisions, decision-making is a crucial cognitive process in our daily life. Psychophysiological theories of heart-brain interactions involvement in cognition predict that general self-regulation capacities underlie cognitive processes including decision-making. Yet, in the context of decision-making, the somatic maker hypothesis postulates that the adaptability of the current physiological state should be the best predictor of advantageous decision-making. The present study tests compare self-regulation in general (indexed by resting vagal activity) and in a specific decisional context (vagal reactivity and recovery) to explain advantageous decision-making. Young adults (n = 54) completed a decision-making task while wearing a heart rate monitor. Bayesian regressions show that vagal reactivity and recovery combined is the preferred statistical model to explain advantageous decision-making (BF10 = 163.85). Those findings 1) support the somatic marker hypothesis highlighting the key role of in situ self-regulation in decision-making processes and 2) show that the popular and often used index of general self-regulation, resting vagal activity, is not the best predictor of decision-making performance, and perhaps even for other cognitive functions. A next step could be interventional studies to test whether vagal modulation of heart rate underlies decision-making through interventions that influence vagal activity, which could provide relevant clinical leads.