A test of abstract thinking and planning, as well as of the ability to change mental set (a temporary readiness to perceive, think or act in a particular way) when circumstances demand it. It consists of 128 cards that differ in color (red, green, yellow, blue), form (circle, triangle, cross, star), and number (one, two, three, four). The task is to try to match them to four target cards by discovering some underlying rule, the tester only providing information as to whether each sort is right or wrong. After a correctly sorted series of ten, the sorting rule is changed without any warning, thus requiring the tested to show flexibility. The main score on this task reflects the number of perseveration errors, observed when a participant gets stuck in a sorting rule that was previously correct, but after the switch to the new sorting rule not any more. It is consider to be a test of executive function, or alternatively of perseveration (meaningless repetition of words, phrases or actions) and thus as an indicator of frontal lobe damage. Its use in assessing children with developmental disorders (e.g., ADHD) has been a topic in a number of publications. The test was originally devised by David A. Grant at the University of Wisconsin, and first published in 1948.
See Attention deficit hyperactivity disorder (ADHD), Attentional flexibility, Cortical lobes, Dorsolateral prefrontal cortex (DLPFC), Executive function (EF), Frontal cortex, Frontal lobe, Inhibitory control
Grant, D. A., & Berg, E. (1948). A behavioral analysis of degree of reinforcement and ease of shifting to new responses in Weigl-type card-sorting problem. Journal of Experimental Psychology, 38, 404-411.