We first conducted analyses to determine whether our physiological measures were sensitive to the valence of our slide stimuli and whether startle responses habituated across pre- and postcessation sessions as expected. We conducted LMM, including all subjects, regressing startle response on stimulus valence and session. We found significant main effects for stimulus valence, F(3, 342) = 131.89, p < .0001, and a significant main effect for session, F(1, 1636) = 18.43, p < .0001 (see Figure 1). To examine possible sex effect on startle response, a second LMM was conducted in which startle response was regressed on sex, stimulus valence, and session. Significant main effects were found for sex, F(1, 113) = 4.93, p < .05, stimulus valence, F(3, 342) = 31.14, p < .0001, and session, F(1, 1626) = 5.94, p < .01. However, no significant interaction among the three predictors was found.
