On the historical and conceptual background of the Wisconsin Card Sorting Test Paul Eling * , Kristianne Derckx, Roald Maes Radboud University Nijmegen, Nici, Biological Psychology, P.O. Box 9104, 6500 HE Nijmegen, The Netherlands Accepted 24 January 2008 Available online 6 March 2008 Abstract In this paper, we describe the development of the Wisconsin Card Sorting Test (WCST). We trace the history of sorting tasks from the studies of Narziss Ach on the psychology of thinking, via the work of Kurt Goldstein and Adhe ´mar Gelb on brain lesioned patients around 1920 and subsequent developments, up to the actual design of the WCST by Harry Harlow, David Grant, and their student Esther Berg. The WCST thus seems to originate from the psychology of thinking (‘Denkpsychologie’), but the test, as it is used in clinical neuropsychological practice, was designed by experimenters working within the behaviorist tradition. We also note recent developments suggesting that, contrary to the general impression, implicit learning may play a role in WCST-like discrimination learning tasks. Ó 2008 Elsevier Inc. All rights reserved. Keywords: Wisconsin Card Sorting Test; Narziss Ach; Thinking; Concept formation; Goldstein; Abstract attitude; Discrimination learning; Executive functions; Frontal lobes 1. Introduction The concept of executive functions has become very popular over the last two decades in clinical (neurological and psychiatric patients) and fundamental (neuroimaging) studies on the (pre-)frontal cortex (e.g., Stuss & Knight, 2002). These executive functions are assumed to serve as cognitive control processes, in particular for planning and organizing behavior. Luria (1966) argued that planning and organization of behavior occur in the prefrontal cor- tex. Clinical neuropsychological evidence seems to support this conclusion. For example, patients with frontal lesions due to traumatic brain injury show symptoms that are referred to as the Dysexecutive Syndrome (Baddeley & Wilson, 1988). Impairments in these executive functions are often assessed with the Wisconsin Card Sorting Test (WCST), along with a range of other instruments. According to Lezak (2004), the WCST is generally used to measure the capacity to deduce concepts and to apply a strategy to adapt behavior to changing conditions. Over the years several variants of the WCST have been devel- oped. In the original version of Berg (1948), switching of the relevant concept (generally referred to as shifting) occurred without a warning by the examiner, whereas this shifting was explicitly announced in the version of Nelson (1976). Heaton, Curtiss, and Tuttle (1993) have introduced a computerized version of the test. A test frequently used in research is the set-shifting subtest of the CANTAB (Fray, Robbins, & Sahakian, 1996). In this paper, we trace the history of the Wisconsin Card Sorting Test (WCST) and similar sorting tasks, beginning with the studies of Narziss Ach on the psychology of think- ing, via the work of Kurt Goldstein and Adhe ´mar Gelb around 1920 and subsequent developments, up to the actual design of the WCST by Harry Harlow, David Grant, and their student Esther Berg at the Wisconsin Uni- versity. What we find interesting is the apparent disconti- nuity, where the cognitive underpinnings of the task are quickly turned intro a Behaviorist framework, and how long it has taken to rediscover its conceptual origins. 0278-2626/$ - see front matter Ó 2008 Elsevier Inc. All rights reserved. doi:10.1016/j.bandc.2008.01.006 * Corresponding author. Fax: +31 24 3616066. E-mail address: p.eling@nici.ru.nl (P. Eling). www.elsevier.com/locate/b&c Available online at www.sciencedirect.com Brain and Cognition 67 (2008) 247–253