The Dimensional Change Card Sort test is a measure of cognitive flexibility. Two target pictures are presented that vary along two dimensions (e.g., shape and color). Participants are asked to match a series of bivalent test pictures (e.g., yellow balls and blue trucks) to the target pictures, first according to one dimension (e.g., color) and then, after a number of trials, according to the other dimension (e.g., shape). "Switch" trials are also employed, in which the participant must change the dimension being matched. Scoring is based on a combination of accuracy and reaction time. Scores can range from 0-10. The higher the score, the better the capacity to switch from one concept to another. The test typically lasts four minutes.