FIGURE 15-8 Wisconsin Card Sorting Test The subject receives a deck of cards containing multiple copies of those represented here and is presented with a row of four cards selected from among them. The task is to place each card in the pile under the appropriate card in the row, sorting by one of three possible categories. Subjects are never explicitly told what the correct sorting category is—color, number, or form; they are told only whether their responses are correct or incorrect. After subjects have begun sorting by one category, the tester unexpectedly changes to another category.