The mediation role of personal and sibling need satisfaction and frustration between perception of sibling relations and interpersonal competence and social anxiety: an actor-partner model.

Introduction: Although SDT has studied the family context considerably, most of the studies have focused on parents, while studies on siblings are still limited. Numerous studies have shown that the siblings relationship is an important factor for psychosocial adjustment, but studies based on the SDT are still limited. For this reason the aim of this study is to investigate the mediation role of need satisfaction and frustration in the relationship between the sibling relationship and anxiety and interpersonal competence in pairs of siblings. In fact to better understand the sibling dynamics, this study use an Actor-Partner Interdependence Model (APIM), that simultaneously test the predictive role of the self-perceptions of both siblings in the prediction of their own variables, and in the prediction of the variables of the other brother. Method: A total number of 1711 pairs of biological siblings (3422 participants) took part to the research and both completed measures about their sibling relations, need satisfaction and need frustration, interpersonal competence and social anxiety. Results: The Actor-Partner Interdependence Model tested showed good fit, χ2(26)=296.40, CFI = .95, RMSEA(90 %CI) = .08 (.07;.09), SRMR = .07, showing that the own perception of sibling relation positively predict the own level of need satisfaction, and negatively predict the own level of need frustration. Furthermore, own level of social anxiety was positively predict by the own level of need frustration, and was negatively predict by the own level of need satisfaction. In addition, own level of interpersonal competence was positively predicted by the own level of need satisfaction, the sibling level of need satisfaction, and the own perception of sibling relation, while it was negatively predicted by own level of need frustration. Finally, own level of need satisfaction positively mediate the relation between sibling relationship and interpersonal competence, while need frustration negatively mediate the relation between sibling relationship and social anxiety. Discussion: Results clearly showed that sibling who experienced high level of positive sibling relations are more likely expire need satisfaction and less need frustration, and in turn this promote interpersonal competence and reduce social anxiety. From a dyadic point of view the results also showed that the own perception of sibling relation and need satisfaction and frustration have a strong role for own level of interpersonal competence and social anxiety, but also that other sibling variables could have also a relevant role.