Pharmacological treatment
To determine the role of noradrenaline and dopamine in the exploration-exploitation tradeoff during human choice, we used a placebo-controlled, double-blind, between-subject design in which participants received orally either a placebo, 40 mg of the β-adrenoceptor antagonist propranolol, or 400 mg of the dopaminergic D2/D3 receptor antagonist amisulpride. The dosages of the drugs were based on previous studies on the role of noradrenaline and dopamine, respectively, in cognitive processes [To verify the action of the drugs, we measured blood pressure and heart rate at several time points before and after drug administration (at baseline and 90, 120, 150 and 180 min after intake of the first pill, see Fig. 