Fig. 1: Schematic of the Pavlovian-to-Instrumental Transfer task.

i. Participants learn instrumental response-outcome associations, namely between a joystick movement (left or right) and the cancellation of an aversive sound (bomb or missile). During each trial, participants are provided with a message stating, ‘Defend Yourself!’ followed by an image of either one of two unconditioned outcomes (bomb or missile). Afterwards, within 30 s, participants are required to respond either left or right to prevent ‘attacks’, which happen every 1.5–3 s. Eighty percent of the time, correct responses are followed by a message stating ‘Avoided’ while 20% of correct or all wrong responses are followed by an image of the outcome and a corresponding unpleasant noise. ii. Participants passively learn stimuli-outcome associations. Three images of galaxies (stimuli, S) are paired with aversive sounds (outcomes) while one galaxy image is ‘safe’ (no associated aversive sound). Stimulus-outcome pairing combinations are counterbalanced across participants. iii. In each trial, galaxies are shown to participants again and they must use the joystick to respond accordingly (as many times as they like within 30 s). The phase probes whether participants can integrate instrumental and Pavlovian learning when responding to the images. This phase is performed under extinction in that no noises are delivered. Key- s: second, S: Conditioned Stimuli.