biostudies-literatureUnknown22(5)Kozunova GLThis study examined whether pupil size and response time would distinguish directed exploration from random exploration and exploitation. Eighty-nine participants performed the two-choice probabilistic learning task while their pupil size and response time were continuously recorded. Using LMM analysis, we estimated differences in the pupil size and response time between the advantageous and disadvantageous choices as a function of learning success, i.e., whether or not a participant has learned the probabilistic contingency between choices and their outcomes. We proposed that before a true value of each choice became known to a decision-maker, both advantageous and disadvantageous choices represented a random exploration of the two options with an equally uncertain outcome, whereas the saCognitive, affective & behavioral neuroscience1108-1129https://www.ebi.ac.uk/biostudies/studies/S-EPMC9458574biostudies-literaturePupil dilation and response slowing distinguish deliberate explorative choices in the probabilistic learning task.PMC9458574Prokofyev AORytikova AMChernyshev BVMedvedev VAKozunova GLSayfulina KEStroganova TAfalsePupil dilation and response slowing distinguish deliberate explorative choices in the probabilistic learning task.This study examined whether pupil size and response time would distinguish directed exploration from random exploration and exploitation. Eighty-nine participants performed the two-choice probabilistic learning task while their pupil size and response time were continuously recorded. Using LMM analysis, we estimated differences in the pupil size and response time between the advantageous and disadvantageous choices as a function of learning success, i.e., whether or not a participant has learned the probabilistic contingency between choices and their outcomes. We proposed that before a true value of each choice became known to a decision-maker, both advantageous and disadvantageous choices represented a random exploration of the two options with an equally uncertain outcome, whereas the sa2022-01-01T00:00:00Z2022 Oct2025-04-04T22:36:08.395Z2025-04-04T22:36:08.395ZS-EPMC94585743535927410.3758/s13415-022-00996-z