Age-related changes in concept formation, rule switching, and perseverative behaviors: A study using WCST with 12 unidimensional target cards

This study examined developmental changes in concept formation, rule switching, and perseverative behaviors of children in the WCST by altering visual features of the test and using a new test score – the ‘zigzag’ error score – which shows the number of shifts made between two incorrect concepts or rules. Instead of the original four 3-dimensional WCST target cards, 12 unidimensional target cards were used in the present study. Consistent with previous research using the original WCST, the results of the current study revealed age-related differences in the unidimensional WCST performance. Six- to seven-year-olds produced more perseverative errors than older children, but as many zigzag errors – shifts between incorrect categories – as the eight- to nine-year-olds did. This suggested that the main difficulty for six- to seven-year-olds was one of the representational inflexibility rather than of switching inflexibility.