Neurocognitive Functioning in AD/HD,Predominantly Inattentive and Combined Subtypes

The Predominantly Inattentive (PI) and Combined (CB) subtypes of AD/HD differ in cognitive tempo, age of onset, gender ratio, and comorbidity, yet a differentiating endophenotype has not been identified. The aim of this study was to test rigorously diagnosed PI, CB, and typical children on measures selected for their potential to reveal hypothesized differences between the subtypes in specific neurocognitive systems (anterior vs. posterior attentional systems) and processes (arousal vs. activation). Thirty-four CB and 26 PI children meeting full DSM-IV criteria for subtype both in school and at home, without confounding reading disability or emotional disorder, were enrolled along with 20 typically developing children. Neurocognitive functions measured included attention, inhibitory control, working memory, learning, and executive functions. Tasks included the Stroop, Wisconsin Card Sorting Test, Continuous Performance Test (CPT). Buschke Selective Reminding Test, ad the Tower of London (TOL), as well as instruments developed by Posner and Sternberg, and tasks assessing the impact on reaction time of [corrected] varying preparatory intervals and stimulus/response complexity. After co-varying for IQ, subtypes differed primarily on measures of impulsivity during tests of vigilance (CPT) and executive function (TOL), with the CB group showing greater impulsivity than both other groups. In addition, the PI group showed worse performance than CB and control groups on the WISC-III Processing Speed Index. Whether analyzed with or without an IQ co-variate, there was no support in the data for hypothesized differences between subtypes in functioning of the anterior vs. posterior attentional systems, nor in involvement of arousal vs. activation processes. The results indicate that the PI and CB subtypes are best differentiated by ratings, observations and tests of cognitive tempo and behavioral impulsivity. Neuropsychological methods have yet to identify critical neuropsychological [corrected] substrates of these differences.     

Reversible operations in the balance scale task

The development of two types of reversible operations was examined in three tasks involving a two-armed balance scale. The first type of reversible operation, compensation between dimensions, was shown to undergo considerable development between eighth grade and college. Even eighth graders were inconsistent in applying compensation to those versions of the balance scale task that required it. Some subjects, primarily preschoolers, used the given information in a way that was the opposite of that required for correct answers, a result that has been reported for other tasks requiring compensation. A second type of reversible operation, termed “correspondence of patterns”, was also tested and it was tentatively concluded that the responses of the modal college student are not fully reversible in this sense. This finding is also similar to results obtained in judgments of time, speed, and distance and in social judgment studies with college students.     

Task parameters affecting the efficacy of a visual imagery learning strategy in younger and older children

Second- and sixth-grade children were presented a list of paired associates (concrete nouns) either at a faster (6-second) or a slower (12-second) presentation rate, under either an instruction to generate an interactive image for the pairs or a no strategy, control instruction. The list was composed of two pair types: easy-to-imaginally relate and difficult-to-imaginally relate pairs, as determined from a prior norming study. At the faster presentation rate, 2nd graders were able to benefit from the imagery strategy with easy pairs, but not with difficult pairs. At the slower rate, however, they applied the imagery strategy equally well to both pair types. Older children benefited from the imagery strategy with both pair types at both rates.     

Effects of timing and justification of witnessed aggression on the observers' punitiveness

Sixty university men who had been treated harshly by the experimenter's accomplice were distributed evenly among four conditions comprising a 2 × 2 factorial design and a “control” group. All of the men watched a moderately aggressive segment from a TV program but in the former case they were given a story summary which depicted the witnessed aggression as either justified or less justified and this summary was provided either immediately before or just after the scene was shown. The fifth group did not have any story synopsis. When the men had an opportunity to punish the confederate at the conclusion of the film, they were nost punitive if they had heard the justified aggression summary after the movie just before they shocked the confederate, and were least punitive if they had been given the nonjustified aggression version before they watched the aggressive incident. These results extend the generality of the findings obtained by other research in this area and also suggest that the violent scene had elicited as well as disinhibited aggression-facilitating reactions in the viewers.     

Is problem solving dependent on language?

There has been a long-standing debate in the fields of philosophy and cognitive science surrounding the relationship of language to cognition, but the exact nature of this relationship is still unclear (Sokolov, 1968/1972). In the current study, we explored the role of language in one aspect of cognition, namely problem solving, by administering the Wisconsin Card Sorting Test (WCST) to stroke patients with varying degrees of language impairment (Experiment 1) and to normal participants under conditions of articulatory suppression (Experiment 2). In Experiment 1, there was a significant correlation between performance on the WCST and language measures such as comprehension and naming. Demonstrating the specificity of this result, we also found a significant relationship between language performance and another test of problem solving, the Raven's Colored Progressive Matrices, but no relationship between language and a test of visuospatial functioning. In Experiment 2, normal participants were significantly impaired on the WCST under conditions of articulatory suppression, relative to a baseline condition. Together, these findings suggest that language plays a role in complex problem solving, possibly through covert language processes.     

Developmental differences in empathy with a television protagonist's fear

An experiment was conducted to determine whether children at different ages (3-5 vs 9-11) differ in their tendency to share the emotion of a television character. Subjects were shown a videotape of either a frightening stimulus alone or a character's fear in response to a threatening stimulus that was suggested rather than shown directly. Contrasting predictions were made based on a cognitive-developmental view of the process of empathy vs an automatic conception. Both self-reported emotional reactions and physiological responses were consistent with the cognitive-developmental approach: The younger children were less emotionally aroused by the character's fear than by the fear-provoking stimulus, while the older children responded emotionally to both versions of the videotape. The younger children's lack of empathy was not due to a failure to recognize the nature of the character's emotion. There was some evidence that the older children exhibited a greater tendency to role take than did the younger children.     

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.     

The Wisconsin Card Sorting Test and the cognitive assessment of prefrontal executive functions: A critical update

For over four decades the Wisconsin Card Sorting Test (WCST) has been one of the most distinctive tests of prefrontal function. Clinical research and recent brain imaging have brought into question the validity and specificity of this test as a marker of frontal dysfunction. Clinical studies with neurological patients have confirmed that, in its traditional form, the WCST fails to discriminate between frontal and non-frontal lesions. In addition, functional brain imaging studies show rapid and widespread activation across frontal and non-frontal brain regions during WCST performance. These studies suggest that the concept of an anatomically pure test of prefrontal function is not only empirically unattainable, but also theoretically inaccurate. The aim of the present review is to examine the causes of these criticisms and to resolve them by incorporating new methodological and conceptual advances in order to improve the construct validity of WCST scores and their relationship to prefrontal executive functions. We conclude that these objectives can be achieved by drawing on theory-guided experimental design, and on precise spatial and temporal sampling of brain activity, and then exemplify this using an integrative model of prefrontal function [i.e., Miller, E. K. (2000). The prefrontal cortex and cognitive control. Nature Reviews Neuroscience, 1, 59–65.] combined with the formal information theoretical approach to cognitive control [Koechlin, E., & Summerfield, C. (2007). An information theoretical approach to prefrontal executive function. Trends in Cognitive Sciences, 11, 229–235.].