Page 132 - Like me, or else... - Michelle Achterberg

Chapter 5
common (shared) environmental factors (C), while dissimilarities are ascribed to unique environmental influences and measurement error (E) (see Figure S3). We used behavioral genetic modeling with the OpenMX package (Neale et al., 2016) in R (R Core Team, 2015) to calculate these A, C, and E estimates (see supplementary materials).
Results
Behavioral aggression following social evaluation
To test whether behavioral aggression decreased with increasing age, we performed a linear mixed-effect model on noise blast duration after feedback across two waves. The linear mixed effect model for noise blast duration showed the expected main effect of type of social feedback (Table S3). Noise blast duration was longer after negative feedback compared to neutral feedback, and shortest after positive feedback (all pairwise comparisons p<.001). We also found the expected main effect of wave (Table S3), with shorter noise blast durations at wave 2 compared to wave 1, indicating a decrease of behavioral aggression over time. Moreover, there was a significant condition ˟ wave interaction effect (Table S3). As can be seen in Figure 1b, noise blast duration decreased more strongly between wave 1 and 2 after positive feedback than after negative feedback (F=23.75, p<.001) and more after positive feedback than after neutral feedback (F=16.27, p<.001). The same result was observed for neutral feedback: noise blast duration decreased more strongly between wave 1 and 2 after neutral feedback than after negative feedback (F=5.00, p=.025). That is, over time children showed a decrease in behavioral aggression, and this effect was most pronounced for aggression following positive feedback, see Figure 1b. We did not find any main or interaction effects of the parental intervention on behavioral aggression (Table S3) and visualization of the data showed large individual differences in aggression regulation in both groups (Figure 1c).
Confirmatory ROI analyses
Confirmatory ROI analyses were performed in two steps: First, we examined neural responses patterns after social feedback across two time points. Second, we examined relations between changes in neural activity and noise blast durations.
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