When the dimensions are the adjectives of the same object, does the performance of three-year-olds increase in the Dimensional Change Sorting Task?

The Dimensional Change Card Sorting (DCCS) task measures the ability to switch from one rule to another (cognitive flexibility). Three-year-old children typically fail in this task, which is widely used in the literature. However, when the dimensions of the things on the cards used in the task are separated, the performance of the three-year-olds increases. There are two close hypotheses about this phenomenon: re-description and mental files. The purpose of this study was to test these two hypotheses with different manipulations on the DCCS task. The three-year-old children participating in the study (N = 38) were given these four tasks: the original DCCS task and a version using objects identical to the original one, and two more versions, one using a constant object instead of card and the other using cards identical to the version using a constant object. In the versions using the constant object, sorting was done through two properties of that thing. As a result, there was no significant difference between these tasks. However, when we divided the group into two using the cut point of 42 months, there were significant differences between these two groups in favor of older age in the original DCCS task and the version using identical objects as the original one. But the differences were still insignificant in the versions using the constant object. Thus, this study supported the hypothesis of mental files, which predicted that rule transition between features of a constant thing would be easier than in the original DCCS task, for three years old children who are younger than 42 months. This is not a direct consequence of the re-description hypothesis