“…Studies on preschoolers have shown that formal instruction is not necessary to understand the inversion concept, although not all children demonstrate understanding (e.g., Baroody & Lai, 2007;Gilmore & Spelke, 2008;Klein & Bisanz, 2000;Sherman & Bisanz, 2007). A number of studies have also examined school-aged children's understanding of the concept (e.g., Bryant, Christie, & Rendu, 1999;Gilmore, 2006;Gilmore & Bryant, 2006;Robinson et al, 2006;Siegler & Stern, 1998;Stern, 1992).…”