Page 49 - Like me, or else... - Michelle Achterberg

Social evaluation in childhood
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adults (only detectable in larger samples and meta-analysis). This was the first study to test whether children engage similar brain regions in processing social evaluation as adults. By using various approaches (whole brain analyses, three different samples, meta-analysis) we had the opportunity to investigate these regions in detail. However, there are several methodological considerations that follow from the current study.
Methodological considerations
First, whole brain analyses in this age range may need larger samples, since the use of fMRI in children is more affected by motion (O'Shaughnessy et al., 2008), but also because there is substantial individual variation in the timing of brain maturation (Pfeifer and Allen, 2016). Some of our independent (one sample) ROI analyses did not show significant effects, while meta-analytically combining the results did reveal significant effects (see for similar results Scheibehenne et al. (2016)). This highlights the importance not only of internal replication but also of incorporating a meta-analytical approach. By applying meta-analysis in the context of one study testing a paradigm in different subsamples, we can minimize the risk that meta-analytic results in the (broader) field of neuroimaging studies are distorted due to publication bias (i.e., the bias resulting from selective publication of significant results (Franco et al., 2014)).
The current study is the first neuroimaging study to use both a replication and meta-analytical approach to test a new experimental paradigm in children. Our test and replication sample consisted of same-sex twin pairs of which the first and second born twin were randomly assigned to one of the two samples. Therefore these samples are not independent, which could result in more equivalent results. However, additional meta-analyses in which we treated the test and replication samples as if they consisted of the same participants (which is too conservative), and then combined the effect size with the effect size of the pilot sample, showed similar combined effect-sizes, with somewhat larger confidence intervals due to the lower N. Moreover, for an exact replication this can be considered an advantage as it reduces the influence of third variables (for example when the replication sample is older or more intelligent), and methodologically this type of replicability is considered one of the important cornerstones of science (Van IJzendoorn, 1994; Gabrieli et al., 2015). Nevertheless, this does have implications for the whole brain analyses with the test and replication samples combined. These are exploratory, and the results need to be confirmed in future larger and independent samples.
Ultimately, results of different, but comparable, social evaluation paradigms in children should be combined to unravel the neural underpinnings of social evaluation in a developmental perspective. Moreover, although the current study shows increased aggression and increased neural activation after rejection, we could not identify significant brain-behavior correlations, probably
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