Page 36 - Like me, or else... - Michelle Achterberg

Chapter 2
insula (from the conjunction contrast of Achterberg et al. (2016b); left and right combined, center of mass (x,y,z) right: 34, 21, 0; left: -32, 20, -6) and the mPFC/ACCg (from the conjunction contrast of (Achterberg et al., 2016b)), see Figure 4a. Parameter estimates (PE, average Beta values) were extracted for the ROI analyses.
Statistical analyses
For noise blast duration, we first computed split-half reliability analyses. Positive, neutral and negative trials were randomly split in half and Pearson’s correlation coefficients were calculated between both halves for each condition in all three samples. Split-half reliability analyses showed that the SNAT displayed excellent reliability in all three conditions: noise blast duration after positive (pilot: r=.85, test: r=.96, replication: r=.96; all p’s<.001), neutral (pilot: r=.83, test: r=.90, replication: r=.89; all p’s<.001) and negative social feedback (pilot: r=.89, test: r=.94, replication: r=.84; all p’s<.001). Next, we used repeated measures ANOVA to investigate the noise blast duration after positive, neutral, and negative feedback in the three samples. Greenhouse-Geisser corrections were applied when the assumption of sphericitiy was violated. Pairwise comparisons were Bonferroni corrected. When outliers were detected (Z-value <-3.29 or >3.29), scores were winsorized (Tabachnick and Fidell, 2013). To compare the behavioral and neural effects over the different samples, we computed combined effect sizes using the Comprehensive Meta-Analysis (CMA) program (Borenstein et al., 2005).
Results
Behavioral results: Noise blast duration
For each of the three samples (pilot, test, and replication) we performed a repeated measures ANOVA on noise blast duration after positive, negative, and neutral feedback. Results of the pilot sample showed a significant main effect of type of social feedback on noise blast duration, F(2, 36)=29.55, p<.001, ω2 = 0.46), see Figure 2. Pairwise comparisons revealed that noise blast duration after negative feedback (M=2718 msec, SD=629) in the pilot sample was significantly longer than noise blast duration after neutral feedback (M=1725 msec; SD=470, p<.001, d= 1.78), and after positive feedback (M=1274 msec; SD=782, p<.001, d= 2.04). Noise blast duration after neutral feedback was significantly longer than after positive feedback (p=.007, d= 0.62). These results were confirmed in the test sample (F(2, 54)=29.72, p<.001, ω2 = 0.30). Participants in the test sample also gave significant longer noise blasts after negative feedback (M=2882 msec;
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