TMS to preSMA, but not rIFG, impacts strategy use in multi-attribute choice

While normative theories of choice advocate for deliberative, rational strategies, models of bounded rationality postulate that humans often rely on fast, simplifying heuristics. We hypothesized that the ability to implement deliberative decision strategies depends on the capacity for response inhibition, subserved by the pre-supplementary motor area (preSMA) and the right inferior frontal gyrus (rIFG). We tested this in a study, in which participants performed a multi-attribute probabilistic inference task following a repetitive transcranial magnetic stimulation (TMS). Continuous theta-burst stimulation (cTBS) has been applied to preSMA, rIFG or a control site (right superior parietal lobule) in a within-subject design. The task involved choosing between two options based on six attributes, presented in compensatory and noncompensatory environments varying in attribute weight distribution. Participants' Need for Closure (NFC) was also assessed as a potential moderator, due to its conceptual relevance and earlier findings highlighting its role in decision-making. cTBS to preSMA selectively modulated strategy use: it enhanced the application of a complex strategy in the compensatory condition and increased the use of a heuristic in the noncompensatory condition. These effects were moderated by NFC, with the strongest effect observed in individuals with low and moderate scores on the NFC scale and its facet Closed-mindedness. No effect was observed following cTBS to rIFG. Assuming that cTBS acted in inhibitory manner, these findings show that inhibiting preSMA enhances the adaptivity of choice processes, particularly in individuals more open to uncertainty, and they support the role of preSMA in flexible cognitive control during decision-making.