Fig. 2: Indices of conditioning and extinction.

a Study inclusion criteria of mean US pleasantness ratings (US pleasantness rating ≥ 0; left panel) and difference scores of rated reward contingencies (CS+minus CS− <−20; right panel) on day 1. b CS pleasantness ratings increased selectively for CS+ from pre to post conditioning, resulting in a significant cue × time interaction (F (1,61) = 4.32, p = .042). During extinction, a general decline in CS pleasantness was observed (main effect of time: F (1,32) = 4.93, p = .034). c Larger SCRs towards the CS + compared to the CS− across both acquisition phases were observed during conditioning (main effect of cue: F (1,59) = 7.08, p = .010). This differentiation was successfully extinguished on day 2 (t(32) = 0.99, p = .329). d Conditioning resulted in marked differences between startle responses during CS+ compared to CS− presentations in a subsequent acoustic startle test. While the eyeblink reflex was attenuated, the PAR was enhanced (p ≤ .005). Differential modulation of startle responses disappeared completely after extinction (p ≥ .894). Note that only a subsample of subjects participating on day 1 (conditioning sample) was further investigated during extinction and reinstatement test. For sample sizes in each measure, please see methods section. Error bars represent within-subject SEM^81,82; a.u., arbitrary units; *p ≤ .05