Scaffolding Multidimensional Understanding and Rule Use in Preschoolers' DCCS Performance
The goal of this dissertation was to examine how specific scaffolding strategies could affect executive functioning (EF) performance in preschool aged children, specifically shifting performance as measured by the Dimension Change Card Sort task (DCCS; Zelazo, 2006). In the DCCS, children must sort test cards initially based on one dimension (e.g., shape) and then switch to sort by another dimension (i.e., colour). When asked to switch rules, 3-year-olds tend to perseverate whereas 5-year-olds can shift successfully. Theoretical accounts center on the notion that children have difficulty successfully representing rules that have embedded if-if-then conditional (Bunge & Zelazo, 2006). If this is true, interventions that are designed to make representing the embedded conditional rule less taxing should lead to better performance on post-switch trials of the DCCS. Given that preschool aged children struggle to describe objects in new ways on the basis of different dimensions (Kloo & Perner, 2005), children may perseverate because they have difficulty reconceptualising the stimuli to match with the post-switch sorting parameters. The studies in this dissertation sought to test the hypothesis that DCCS performance could be scaffolded by promoting children’s attention to the multidimensional nature of objects. In Study 1 and 2, brief experimental games were used to scaffold 3-year-old children’s ability to think about the multidimensional nature of objects by both separating and aggregating dimensions. Results showed that promoting multidimensional understanding facilitated DCCS performance relative to controls. Moreover, it seems that this is the case regardless of the nature of the scaffolding dimensions. In Study 3, we included an additional extra-dimensional sorting parameter, order, in an attempt to facilitate performance on a more advanced version of the DCCS in 5-year-olds. Again, children in the experimental condition performed significantly better relative to controls, suggesting that difficulty conceptualizing objects in different ways may be a critical component of shifting performance across the preschool age range. The findings will be discussed with regard to their theoretical implications concerning the nature of EF development more broadly, and shifting more specifically, and their potential to inform research with children who may be at risk for difficulties with shifting.