Flipbook

CHAPTER 2 44 In the Test phase, threat expectancy showed a main effect of Stimulus F (2,110) = 624.97, p < .001, η p 2 = .92, Condition, F (1,55) = 168.39, p < .001, η p 2 = .75, and, crucially, a Stimulus x Condition interaction, F (2,110) = 159.38, p < .001, η p 2 = .74. Threat expectancy was higher for A than for B, F (1,55) = 1424.60, p < .001, η p 2 = .96. This did not differ between conditions, F (1,55) = 1.32, p = .26, η p 2 = .02, or show a Stimulus x Condition interaction, F (1,55) = 1.50, p = .23, η p 2 = .03. In line with our hypothesis, threat expectancy for C was higher in the Full avoidance condition than in the Control condition (see Figure 1, C- in the Test phase is higher in the top panel than in the bottom panel), t (28.90) = 18.30, p < .001, d = 4.77. To further decompose the Stimulus x Condition interaction, we examined threat expectancy for C compared with the danger stimulus (A) and safety stimulus (B) in the Test phase for each condition. In line with our hypothesis, in the Control condition, threat expectancy was lower for C than for A, t (28) = 13.21, p < .001, d = 3.26, and higher for C than for B, t (28) = 2.77, p = .01, d = 0.73 (see Figure 1, C is lower than A, and higher than B in the bottom panel). This indicates that extinction for C occurred in the Control condition. In the Full avoidance condition, threat expectancy for C was also higher than for B, t (27) = 97.82, p < .001, d = 35.72, but it did not differ between A and C, t (27) = 1.30, p = .20, d = 0.22 (see Figure 1, C is similar to A, and higher than B in the top panel). Thus, threat expectancy for C was maintained in the Full avoidance group. Pupil dilations As depicted in Figure 2, the conditioning effect observed on threat expectancy was not reflected in pupil dilations. At the end of the Pavlovian acquisition phase, pupil dilation responses did not differ between A, B, and C, F < 1, between conditions, F (1,54) = 2.97, p = .09, η p 2 = .05, or show a Stimulus x Condition interaction, F (2,108) = 1.70, p = .19, η p 2 = .03. However, pupil dilation responses increased on full avoidance and subtle safety behavior trials. In the Safety behavior acquisition phase, pupil dilation responses were larger on full avoidance trials (see the A*(+) trials in Figure 2), F (1,54) = 14.67, p < .001, η p 2 = .21, and subtle safety behavior trials (see the A~[+]