“…As boys navigate the task of developing an increasingly stable and coherent self-concept, their family members, peer groups, and the media play an important role in shaping their identities and beliefs (Blatt & Blass, 1996;Maccoby & Martin, 1993;. Further, boys' investment in their relationships may make them vulnerable to external influences, such as pressures from friends or the media to adopt the physical ideal (Clabaugh, Karpinski, & Griffin, 2008;Crocker, 2002;Vartanian, 2009), and likely to internalize or incorporate the beliefs and values (e.g., characteristics of masculinity) of their peers, family members, and society into their self-schema (Drummond, 2002;Vartanian & Hopkinson, 2010). Because middle school boys spend considerable time at school among their peers (Myers & Crowther, 2009), they would be attentive to the appearance norms that are salient within their friendships and social networks (Grieve, 2007;Grieve & Helmick, 2008), which are likely to include a focus on the thinness and muscle tone of their bodies (Murnen, 2011).…”