Reduced Pavlovian value updating alters decision-making in sign-trackers

This study examines how interindividual differences in Pavlovian learning, specifically in sign-trackers and goal-trackers, shape Pavlovian bias in decision-making. Using a three-phase Pavlovian-to-Instrumental Transfer task in humans, combined with computational modeling and pupillometry, we found that although both groups learned optimal decision-making strategies, sign-trackers more frequently deviated from them when exposed to Pavlovian cues, favoring suboptimal options linked via the cue-outcome association. A dynamic arbitration model revealed that this effect was due to slower updating of Pavlovian cue values during the transfer phase, rather than overvaluation of the cue relative to instrumental actions. These findings offer a computational framework for understanding rigid decision patterns and may inform interventions for disorders marked by maladaptive cue reactivity.