Investigating the Cognitive Edge: Could tDCS Influence Curiosity and Decision-Making Under Cognitive Load?

Decision-making in unknown circumstances requires balancing exploitation—leveraging past outcomes—and exploration—seeking new information—a process often constrained by cognitive load. Cognitive load may impede curiosity-driven inquiry and diminish working memory capacity, leading to less adaptive but safer selections. While previous research has shown that transcranial direct current stimulation (tDCS) applied to the dorsolateral prefrontal cortex (DLPFC) enhances cognitive flexibility and risk-taking behavior, there is limited understanding of its efficacy in mitigating the adverse impacts of higher cognitive load on the exploration-exploitation trade-off. By examining how tDCS influences decision-making under various cognitive demands, our work fills this research gap. Under low and high cognitive load settings, 20 participants, 10 receiving tDCS (tDCS group) and 10 not receiving tDCS (control group), choose between three alternatives in a binary-choice task: safe option (Option A), risky option (Option B), and exploratory option (Option R). Results revealed that those who received tDCS were more likely to engage in exploratory behavior, choosing Option <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$R$</tex> in 40 % of trials as opposed to 22 % in the control group, and selected riskier alternatives (Option B) in 57.7 % of trials, which was considerably more frequent than the control group (31 %). Interestingly, even when subjected to a high cognitive load, tDCS individuals retained the choice for the option <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$R$</tex>, underscoring the function of neuromodulation in reducing the impact of higher cognitive load. With implications for risky situations, these findings advance our knowledge of how tDCS fosters curiosity-driven behavior through enhancement in exploratory behavior and adaptive decision-making.