One of the developing skills in executive functions is the flexible control of selective attention. Young children improve in this ability during the preschool years as measured by such tasks as the Dimension Change Card Sort (DCCS) which asks children to sort pictures, first by one dimension (e.g. color), and then by another (e.g. shape). Three-year-olds sort correctly by the first dimension, but do not sort correctly when the rule changes (i.e., they perseverate). By five, children switch flexibly between dimensions. This study asks about the relationship between perseveration in the DCCS and dimensional word knowledge which also improves during preschool years. Thirty children participated in a study which tests knowledge of feature terms (e.g., red, blue) and dimension terms (e.g. color, shape). Results indicate no difference in knowledge of feature terms for the two groups, but children who switch successfully in the DCCS were significantly better at dimension terms.