“…Sibling composition provides an interesting test case because several studies have shown that 3-to 6-year-olds with more siblings, especially older siblings, demonstrate superior ToM performance compared with children with fewer or no siblings (e.g., Farhadian, Gazanizad, & Shakerian, 2011;Lewis, Freeman, Kyriakidou, Maridaki-Kassotaki, & Berridge, 1996;McCalister & Peterson, 2006, 2007, 2013Perner et al, 1994;Ruffman, Perner, Naito, Parkin, & Clements, 1998;Wolfe, Want, & Siegal, 2003; but see Carlson & Moses, 2001;Cole & Mitchell, 2000;Cutting &Dunn, 1999, andHughes &Ensor, 2005, for examples of null effects). Researchers have interpreted these data to indicate that siblings provide social opportunities that improve young children's knowledge about mental states, with older siblings being particularly advantageous because they serve as social mentors to the younger ''apprentices'' (Hughes et al, 2014;Perner et al, 1994;Ruffman et al, 1998).…”