The Role of Switching,Inhibition and Working Memory in Older Adults' Performance in the Wisconsin Card Sorting Test

ABSTRACT

The Wisconsin Card Sorting Test (WCST) is considered a typical executive test. However, several interesting questions are still open as to the specific executive processes underlying this task. In the present study, we explored how local and global switching, inhibition and working memory, assessed through the Number–Letter, the Stop Signal and the Reading Span tasks, relate to older adults' performance in the WCST. Results showed that older adults' performance variability in the number of perseverative errors was predicted by the local switch component of the Number–Letter task. Results also showed age-related differences in inhibition, working memory and global switching, while local switching resulted largely spared in aging. This study provides evidence that switching abilities may contribute to performance of older adults in the WCST. It also provides initial evidence suggesting that switching processes, associated with local switch costs, are involved in performance on the WCST, at least in older adults.     

Reduction of perseverative errors in patients with schizophrenia using monetary feedback.

The influence of monetary feedback on Wisconsin Card Sort Test (WCST) performance of 14 male schizophrenics was investigated. Patients were administered the test under standard instructions and with monetary feedback in counterbalanced order. Monetary reinforcement reduced perseverative errors and increased correct responses (p less than .05). These findings suggest that the WCST perseverative errors of schizophrenics reflect motivational as well as cognitive factors.     

Deficits in set-shifting ability in nonclinical compulsive checkers

Recent studies suggest deficits in set-shifting ability in patients with obsessive-compulsive disorder (OCD) as measured by tasks such as the Wisconsin Card Sorting Test (WCST; Berg, 1948). The present study examined the extent to which these deficits were demonstrated by nonclinical subjects selected on the basis of their checking scores on the Maudsley Obsessional-Compulsive Inventory. A multivariate analysis revealed that frequent checkers performed significantly worse on the WCST than noncheckers, making more total errors and more perseverative errors and requiring more time to complete the test. A follow-up analysis on a subset of the original sample found similar performance deficits in checkers. While the poorer performance of checkers could be statistically accounted for by anxiety during the first administration of the WCST, anxiety could not explain the relationship between checking status and WCST performance at follow-up. Therefore, there does appear to be some relationship between checking status and WCST performance beyond what can be explained by affective variables.     

Childhood abuse and neglect and cognitive flexibility in adolescents

Childhood maltreatment (CM) has been associated with diminished executive functioning in children and adults; however, there is a relative paucity of study of executive function in adolescents exposed to CM. Yet, executive dysfunction in adolescence may have important adverse consequences including increased vulnerability to risky behaviors and impaired school functioning. This study investigates the relationship between self-reported CM and an executive function, cognitive flexibility, in adolescents without identified psychiatric disorders. Effects of physical and emotional, abuse and neglect, maltreatment subtypes were explored. Thirty adolescents ages 12-17 years, 50% females, completed the retrospective self-report Childhood Trauma Questionnaire (CTQ) and were administered the Wisconsin Card Sorting Test (WCST). Correlational analyses assessed the relationship between WCST perseverative error scores norm-referenced for age and education with CTQ total scores. The relationship with nonperseverative errors, as well as with physical and emotional abuse and neglect CM subscores, were explored. Total CTQ scores showed significant associations with perseverative errors on the WCST, but not with nonperseverative errors. Significant associations with perseverative errors were seen for physical abuse and physical neglect among the CTQ subscales. The results suggest both physical abuse and physical neglect are associated with diminished cognitive flexibility in adolescents. These effects were detected in adolescents without identified psychiatric diagnoses suggesting the importance of considering executive dysfunction in adolescents exposed to CM who may not meet diagnostic criteria for an Axis I disorder and that tests of perseverative errors, such as those of the WCST, may be sensitive indicators of this dysfunction.     

Social transmission of disinhibition in young children

The present study examined whether young children's behaviors in the Dimensional Change Card Sorting task can be influenced by their observation of another person performing the task. Experiment 1 showed that after children watched an adult sorting cards according to one rule, although the children were instructed to sort the cards according to a new rule, most 3-year-olds made perseverative errors and used the observed, old rule to sort the cards instead of the new rule. However, only some 4-year-olds and few 5-year-olds made the same mistake. Experiments 2, 3 and 4 showed that the younger children took into consideration social pragmatic information displayed by the adult model when deciding to use the old rule or the new rule. When the model appeared to know that she sorted the cards incorrectly (Experiments 2 and 3), or was uncertain whether she sorted cards correctly (Experiment 4), most 3-year-olds no longer committed perseverative errors. When the adult model was confident about her sorting or oblivious to her sorting errors, most 3-year-olds made perseverative errors. These results taken together suggest that social observation can lead to disinhibitions. In other words, disinhibition can be transmitted socially from one person to another.     

The impact of frontal and non-frontal brain tumor lesions on Wisconsin Card Sorting Test performance

Several lesion and imaging studies have suggested that the Wisconsin Card Sorting Test (WCST) is a measure of executive dysfunction. However, some studies have reported that this measure has poor anatomical specificity because patients with either frontal or non-frontal focal lesions exhibit similar performance. This study examined 25 frontal, 20 non-frontal low-grade brain tumor patients, and 63 normal controls (NC) on the WCST. The frontal patients were also assigned to either a left frontal (n=10) group or a right frontal group (n=15) and compared with the non-frontal group and NC. It was hypothesized that the frontal brain tumor patients would display greater deficits on categories achieved and a higher number of perseverative errors than non-frontal brain tumor patients on the WCST. Finally, it was predicted that right frontal brain tumors would result in greater executive functioning deficits than left frontal or non-frontal brain tumors. Results indicated that the left frontal group achieved the fewest categories and committed the most perseverative errors compared to the other patient and normal control groups. In addition, the left frontal group committed significantly more perseverative errors than the right frontal group. These results suggest that the WCST is sensitive to the effects of low-grade brain tumors on executive functioning.     

Children perseverate to a human's actions but not to a robot's actions

Previous research has shown that young children commit perseverative errors from their observation of another person's actions. The present study examined how social observation would lead children to perseverative tendencies, using a robot. In Experiment 1, preschoolers watched either a human model or a robot sorting cards according to one dimension (e.g. shape), after which they were asked to sort according to a different dimension (e.g. colour). The results showed that children's behaviours in the task were significantly influenced by the human model's actions but not by the robot's actions. Experiment 2 excluded the possibility that children's behaviours were not affected by the robot's actions because they did not observe its actions. We concluded that children's perseverative errors from social observation resulted, in part, from their socio-cognitive ability.     

Switching between spatial stimulus-response mappings: a developmental study of cognitive flexibility

Four different age groups (8-9-year-olds, 11-12-year-olds, 13-15-year-olds and young adults) performed a spatial rule-switch task in which the sorting rule had to be detected on the basis of feedback or on the basis of switch cues. Performance errors were examined on the basis of a recently introduced method of error scoring for the Wisconsin Card Sorting Task (WCST; Barcelo & Knight, 2002). This method allowed us to differentiate between errors due to failure-to-maintain-set (distraction errors) and errors due to failure-to-switch-set (perseverative errors). The anticipated age differences in performance errors were most pronounced for perseverative errors between 8-9 years and 11-12 years, but for distraction errors adult levels were not reached until 13-15 years. These findings were interpreted to support the notion that set switching and set maintenance follow distinct developmental trajectories.     

Cognitive flexibility in preschoolers: the role of representation activation and maintenance

Preschoolers' lack of cognitive flexibility has often been attributed to perseverative processing. This study investigates alternative potential sources of difficulty such as deficits in activating previously ignored information and in maintaining currently relevant information. In Experiment 1, a new task tapping attentional switching was designed to isolate the difficulty of overriding an initial representation, that is, perseverative processing ('Perseveration' version), and the difficulty of activating a previously ignored representation, that is, activation deficit ('Activation-deficit' version). Three-year-olds' performance suggested that inflexibility may primarily stem from an activation deficit. Control experiments confirmed that the difficulty of the 'Activation-deficit' version could not be attributed to the effect of attraction to novelty. In Experiment 2, 'distraction' errors, alleged to reflect a failure to maintain a relevant representation, and 'perseverative' errors were distinguished. The results highlighted the important role of representation maintenance in flexibility. The present study indicates that preschoolers' lack of cognitive flexibility is multi-determined and prompts us to reconsider the role of perseveration.     

Representation and Perseveration: Influences on Young Children's Representational Insight

We carried out 3 experiments to determine what role different task demands play in 2.5-year-old children's performance on DeLoache's (1987) model-room task. The results of Experiment 1 reveal that the size of the toy to be retrieved had little bearing on performance; only the size of the spaces affected performance. Experiment 2 demonstrated that the large number of perseverative errors produced by children in these tasks was not reduced when the toy on each of the 4 test trials was changed and, thus, further suggested that characteristics of the toy had little influence on performance. Experiment 3 showed that elimination of the possibility of perseverative response through removal of the previously used hiding locations did not facilitate transfer. The results point to conceptual inflexibility or difficulty of engagement in dual representation associated with the search space as important contributors to the lack of representational insight demonstrated by 2.5-year-old children.     

I'm sitting here feeling aphasic! A study of recurrent perseverative errors elicited in unimpaired speakers

In this study, the recurrent perseverative errors produced by 44 speakers without impairment were examined in picture naming and reading aloud tasks under a fast response deadline. The proportion of perseverative relative to non-perseverative errors was greater in picture naming, the more error-prone task, than in reading aloud. Additionally, although perseverative errors were less likely to be related to the target than non-perseverative errors, the overall distribution of perseverative and non-perseverative errors in each task was similar. It is concluded that the perseverative errors produced by the participants reflected both the degree and level at which language processing efficiency was reduced in each task. This is consistent with a more recent account of perseveration as a result of normally existing persistent activation overcoming weakened activation of a target at any level of language processing. These results are compared with recent studies of recurrent perseverative errors produced by people with aphasia in light of the cognitive neuropsychological assumption that speakers with and without impairment utilise a common language processing system.     

Age-related differences in performance on the Wisconsin card sorting test: a meta-analytic review

Two meta-analyses investigating age-related differences in performance on a popular measure of executive function, the Wisconsin Card Sorting Test (WCST), are reported. The 1st meta-analysis examined age-related changes in performance for the number of categories achieved, and the 2nd meta-analysis examined performance for the number of perseverative errors committed. Results indicated that robust age differences were present on both measures. Further analysis of moderator variables revealed reliable effects of education and test version on both measures, whereas test modality led to marginally significant differences in effect sizes obtained only for the number of categories achieved. Findings are discussed along with current accounts of age differences in performance of the WCST.     

An attempt to discriminate different types of executive functions in the Wisconsin Card Sorting Test

This study examined the roles of the phonological working memory and the central executive in the Wisconsin Card Sorting Test by altering the materials and the procedure of the task and using a dual-task design, in which cognitive abilities of normal participants were manipulated by performance of the secondary tasks selectively taxing the phonological loop or the central executive. The present study used three novel versions of the Wisconsin Card Sorting Test, namely the WCST-4 stimuli, the WCST-12-stimuli, and the WCST-12-stimuli-box, in all of which the participants were given the exact sorting criterion. So the tasks did not involve processes such as maintenance of inferences about the sorting criterion which would require phonological memory load. However, the tasks were assumed to require the executive process of response inhibition. In the WCST-4-stimuli condition no change was made to the WCST materials. In the other two conditions, relying on the assumption that the three-dimensional nature of the cards triggers inappropriate responses, unidimensional stimulus cards were used instead of the four normal three-dimensional WCST stimulus cards. The difference between these two conditions was that, in the WCST-12-stimuli-box condition, boxes were used to conceal the response cards previously sorted. The results supported Dunbar and Sussman's (1995) argument that some executive processes in the Wisconsin Card Sorting Test require the use of phonological store, and the present design was able to differentiate the type of executive functions that do not involve the use of a phonological loop from the ones that do. In addition, the results concerning manipulations of the visual aspects of the Wisconsin Card Sorting Test suggest that the three-dimensional nature of the WCST stimulus cards leads to an increase in the number of inappropriate responses produced with the executive secondary task interference.     

Improving postswitch performance in the dimensional change card-sorting task: the importance of the switch and of pretraining by redescribing the test cards

The dimensional change card-sorting task (DCCS) is used to assess the executive abilities of young children. Typically, 3-year-olds have difficulty in performing this task. However, the exact nature of this difficulty is still being debated. In the standard DCCS, children need to sort, for example, test cards with a blue flower or a red car into two boxes marked with the target cards. The 3-year-olds commonly have pronounced difficulty in switching from one sorting criterion (e.g., color) to another (e.g., shape). Here two experiments with 3-year-olds showed that making the transition between the sorting criteria more distinct improved performance significantly. This was achieved by taking away the target cards for a brief time period, asking a question irrelevant to the task, and pretraining the children by redescribing the test cards.     

Older, not younger, children learn more false facts from stories

Early school-aged children listened to stories that contained correct and incorrect facts. All ages answered more questions correctly after having heard the correct fact in the story. Only the older children, however, produced story errors on a later general knowledge test. Source errors did not drive the increased suggestibility in older children, as they were better at remembering source than were the younger children. Instead, different processes are involved in learning correct and incorrect facts from fictional sources. All ages benefited from hearing correct answers because they activated a pre-existing semantic network. Older children, however, were better able to form memories of the misinformation and thus showed greater suggestibility on the general knowledge test.     

A simple but powerful test of perseverative search in dogs and toddlers

Perseverative (A-not-B) errors during the search of a hidden object were recently described in both dogs and 10-month-old infants. It was found that ostensive cues indicating a communicative intent of the person who hides the object played a major role in eliciting perseverative errors in both species. However, the employed experimental set-up gave rise to several alternative explanations regarding the source of these errors. Here we present a simplified protocol that eliminates the ambiguities present in the original design. Using five consecutive object hiding events to one of two locations in a fixed order (“AABBA”), we tested adult companion dogs and human children (24 months old). The experimenter performed the hiding actions while giving ostensive cues in each trial and moved the target object to the given location in a straight line. Our results show that in the B trials, both 24-month-old children and dogs could not reliably find the hidden object, and their performance in the first B trials was significantly below that of any of the A trials. These results are the first to show that the tendency for perseverative errors in an ostensive-communicative context is a robust phenomenon among 2-year-old children and dogs, and not the by-product of a topographically elaborate hiding event.     

Young children's difficulty with inhibitory control in a social context1

Abstract: The authors’ prior research has documented that young children's behaviors in the Dimensional Change Card Sorting (DCCS) task can be influenced by their observation of another person performing the task and has suggested that young children committed perseverative errors in a social context. The present study explored whether children who committed perseverative errors in the social context also committed perseverative errors in the standard DCCS task. Three‐ and 4‐year‐old children were given the standard DCCS and the observation version of the DCCS, and the relationship between them was examined. The results showed that the correlation between these two tasks was significant. Furthermore, 4‐year‐old children displayed more difficulty in the observation version than in the standard DCCS, whereas 3‐year‐olds did not. The results are discussed in terms of the development of inhibitory control and social cognition.     

Effect of treatment with stimulant medication on nonverbal executive function and visuomotor speed in children with attention deficit/hyperactivity disorder (ADHD).

This study used a novel hidden maze learning test to examine the nature and magnitude of impairment on separable aspects of executive function in 36 children with ADHD. A within-subject analysis of children with ADHD was also conducted to assess cognitive effects of open-label stimulant treatment. Compared to 31 age-matched controls, unmedicated children with ADHD were slower and made significantly more errors that were indicative of relative impairment in prepotent response inhibition and ability to "maintain set" while using simple rules to complete the task. Open-label administration of stimulant medication led to faster and more efficient performance, with children with ADHD making fewer perseverative and rule-break errors than when off medication. This instrument might be useful in monitoring treatment response in specific aspects of executive function and in assisting with dose-titration decisions.     

Sequential learning models for the Wisconsin card sort task: Assessing processes in substance dependent individuals

The Wisconsin card sort task (WCST) is a commonly used neuropsychological test of executive or frontal lobe functioning. Traditional behavioral measures from the task (e.g., perseverative errors) distinguish healthy controls from clinical populations, but such measures can be difficult to interpret. In an attempt to supplement traditional measures, we developed and tested a family of sequential learning models that allowed for estimation of processes at the individual subject level in the WCST. Testing the model with substance dependent individuals and healthy controls, the model parameters significantly predicted group membership, even when controlling for traditional behavioral measures from the task. Substance dependence was associated with (a) slower attention shifting following punished trials and (b) reduced decision consistency. Results suggest that model parameters may offer both incremental content validity and incremental predictive validity.     

Mental fatigue and the control of cognitive processes: effects on perseveration and planning

We tested whether behavioural manifestations of mental fatigue may be linked to compromised executive control, which refers to the ability to regulate perceptual and motor processes for goal-directed behaviour. In complex tasks, compromised executive control may become manifest as decreased flexibility and sub-optimal planning. In the study we use the Wisconsin Card Sorting Test (WCST) and the Tower of London (TOL), which respectively measure flexibility (e.g., perseverative errors) and planning. A simple memory task was used as a control measure. Fatigue was induced through working for 2 h on cognitively demanding tasks. The results showed that compared to a non-fatigued group, fatigued participants displayed more perseveration on the WCST and showed prolonged planning time on the TOL. Fatigue did not affect performance on the simple memory task. These findings indicate compromised executive control under fatigue, which may explain the typical errors and sub-optimal performance that are often found in fatigued people.