Before revision:  We studied four groups with nine different compositions and 18 individual transfers to study 1. ) the effect of group composition on individual social centralities and 2. ) the effect of group composition changes on these centralities.
After revision:  Four groups with nine different compositions and 18 individual transfers to study 1. ) the effect of group composition on individual social centralities and 2. ) the effect of group composition changes on these centralities.