“…Several studies have recently argued that these effects largely depend on the quality of the relationship (Lockwood, Kitzmann, & Cohen, 2001) and on the way that siblings judge their relationship (Stormshack, Bellanti, & Bierman, 1996;Woolfe, Want, & Siegal, 2003). That is, those children who have a positive relationship with their sibling show greater understanding of other people's feelings and beliefs (Dunn, Brown, Slomkowski, Tesla, & Youngblade, 1991;Howe & Ross, 1990) and higher social adjustment Updegraff, McHale, & Crouter, 2002). By contrast, a conflictual sibling relationship seems to foster aggressive behaviour (Garcia, Shaw, Winslow, & Yaggi, 2000).…”