Figure 2.

Acquisition and extinction of avoidance behavior, represented by percentage of time spent hiding during the warning period in (A) male participants with and without SS (n = 26 and 29, respectively), and in (B) female participants with and without SS (n = 34 and 32, respectively). On the acquisition phase, sex was the best predictor of performance (stepwise linear regression, p = 0.007). Post hoc regression analyses separately for each sex revealed that females’ hiding could be predicted by the experimental group (with-SS versus without-SS; p = 0.023). On the extinction phase, performance was best predicted by level of acquisition responding and experimental group (p < 0.001). Vertical gray lines represent the end of the acquisition phase. Error bars indicate SEM.