Figure 2: Online shock-expectancy ratings (upper graph) and Z-transformed skin conductance reactivity (lower graph) of Experiment 2. During the first phase, group Pre-exposure was exposed to the to-be-conditioned stimuli, whereas group Control was exposed to irrelevant stimuli (12 trials). The groups were identical in the remaining phases (conditioning, 8 trials, and extinction, 12 trials). CS+ was 6 times followed by the US during conditioning, whereas CS- was never followed by the US.