Figure 1.
Stimuli and design. A, Conditions and stimuli used in this experiment. Stimulus to condition mappings were counterbalanced across participants. B, Trial structure in the conditioning and reversal phases, separately for each CS condition. The lightning bolt represents reinforcement, which was administered on 33% of the CS+E trials. In the reversal phase, stimuli were instructed to be either safe or threatening, but no stimuli were reinforced. Here, CS– included (CS+Ereversed, CS+Ireversed, CS–nonreversed), and CS+ included (CS+Enonreversed, CS+Inonreversed, CS–reversed) CS = conditions stimulus, CS– = safe stimulus, CS+I = merely instructed stimulus, CS+E = instructed and experienced stimulus.