MONETARY REINFORCEMENT AND WISCONSIN CARD SORTING PERFORMANCE IN SCHIZOPHRENIA - WHY SHOW ME THE MONEY

The Wisconsin Card Sorting Test (WCST) is a measure of concept formati on and cognitive flexibility that has been associated with the integri ty of the dorsolateral prefrontal cortex. Although patients show defic its on the WCST, training techniques that rely on enhanced instruction are often effective at improving performance, at least temporarily. T he beneficial effects of monetary reinforcement alone, however, have n ot shown such clear-cut effects. Thirty-two schizophrenic inpatients w ere initially administered a computerized version of the WCST accordin g to standard instructions and then assigned to one of four groups tha t differed by type of intervention. The level of reinforcement (high v s. low) and enhanced instruction (present vs. absent) were manipulated across the four groups. All patients received a repeat standard admin istration of the WCST at a I-week follow-up. Although enhanced instruc tion showed an initial effect, performance gains fell off at the 1-wee k retest and approached baseline levels of performance. The level of r einforcement did not make a significant difference. The results indica te that the addition of enhanced verbal instruction yields a benefit, but that contingent monetary reinforcement does not. It appears that d eficits on this test are not easily remediated by incentive manipulati ons. (C) 1998 Elsevier Science B.V. All rights reserved.