“…Consistent evidence has emerged that adolescents' use of pornography is related to stronger permissive sexual attitudes (Brown & L'Engle, 2009, only boys;Doornwaard, Bickham, et al, 2015, only boys;Lo et al, 1999;Lo & Wei, 2005;Peter & Valkenburg, 2006bTo et al, 2015;To et al, 2012). Most evidence is based on cross-sectional surveys (Lo et al, 1999;Lo & Wei, 2005;Peter & Valkenburg, 2006bTo et al, 2015;To et al, 2012). The sizes of the associations in cross-sectional studies ranged from Cohen's d = 0.45 (Lo et al, 1999) to d = 0.72 (Peter & Valkenburg, 2008b), with an average of d = 0.56 across the studies.…”