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Demonstrating a specific cognitive deficit usually involves comparing patients' performance on 2 or more tests, The psychometric confound occurs if the psychometric properties of these tests lead patients to show greater cognitive deficits in 1 domain. One way to avoid the psychometric confound is to use tests with a similar level of discriminating power, which is a test's ability to index true individual differences in classic psychometric theory. One suggested way to measure discriminating power is to calculate true score variance (L. J. Chapman & J. P. Chapman, 1978). Despite the centrality of these formulations, there is no systematic examination of the relationship between the observable property of true score variance and the latent property of discriminating power. The authors simulated administrations of free response tests and forced choice tests by creating different replicable ability scores for 2 groups, across a wide range of various psychometric properties (i.e., difficulty, reliability, observed variance, and number of items), and computing an ideal index of discriminating power. Simulation results indicated that true score variance had only limited ability to predict discriminating power (explained about 10% of variance in replicable ability scores). Furthermore, the ability varied across tests with wide ranges of psychometric variables, such as difficulty, observed variance, reliability, and number of items. Discriminating power depends on a complicated interaction of psychometric properties that is not well estimated solely by a test's true score variance. Keywords: differential deficit, generalized deficit, psychometric confound, discriminating power, simu- lation study DOI: 10.1037/a0018400

The role of catechol-O-methyltransferase (COMT) va1158met in prefrontal cortical deficits associated with the liability to schizophrenia remains controversial. This study evaluated 464 healthy adult participants using three measures of executive functions in working memory: a 3-back version of the N-back continuous performance task (CPT) and two variants of the AX-CPT. The interpretability of N-back performance was confounded by possible generalized deficits, whereas the AX variants included internal controls for uncovering specific deficits. There was no relationship between the COMT genotype and N-back performance, whereas val/val individuals had a specific deficit on a dot-pattern version of the AX-CPT. In this case, a specific executive function known as context processing appeared to be compromised. These data suggest that the interpretability gained by including task manipulations to uncover specific deficits can enhance associations between cognitive and genetic levels of analysis. Keywords: schizophrenia, COMT, working memory, context processing, psychometric confound

Context processing is conceptualized as an executive function involved in voluntary, complex actions such as overcoming automatic responses. The present study tested the hypothesis that context-processing deficits in patients with schizophrenia are associated with a dysfunction of left dorsolateral prefrontal cortex (DLPFC). Using event-related functional magnetic resonance imaging (fMRI), 17 controls and 17 medicated patients performed a version of the AX task in which a learned, automatic response had to be inhibited. In controls, left DLPFC activity increased when preparing to overcome an automatic response, whereas patients with schizophrenia showed no differential activation. In controls, context processing appeared to be associated with the differential representation of cues associated with the need to provide top--down support for overcoming automatic responses. This mechanism appeared to be impaired in patients with schizophrenia.

Previous research on schizophrenia suggests that context-processing disturbances are one of the core cognitive deficits present in schizophrenia. However, it is not clear whether such deficits are specific to schizophrenia as compared with other psychotic disorders. To address this question, the authors administered a version of the AX Continuous Performance Test designed to assess context processing in a sample of healthy controls, patients with schizophrenia, and patients with other psychotic disorders. Participants were tested at index (when medication naive and experiencing their first contact with psychiatric services) and 4 weeks later, following medication treatment. At index, patients with schizophrenia and the psychotic comparison group demonstrated similar impairments in context processing. However, context-processing deficits improved in the psychotic comparison group at 4 weeks but did not improve in patients with schizophrenia.

In the context of a school-based prevention of conduct disorder program, 7,231 first- through fourth-grade children were screened for cross-setting disruptive behavior. Frequencies of DSM-III-R psychiatric disorders and patterns of comorbidity were assessed. We also examined the association of psychiatric diagnosis with child and parent characteristics to determine differential risk based on diagnostic subgroups. Attention deficit hyperactivity disorder (ADHD) and oppositional-defiant disorder (ODD) were the most frequent diagnoses. Mood and anxiety disorders were infrequent as single diagnoses. Patterns of comorbidity demonstrated that both externalizing and internalizing disorders commonly cooccurred with ADHD. More severe degrees of psychopathology and psychosocial risk accrued to the subgroup of youths with ADHD plus a comorbid externalizing disorder.

Community-based multiple gate screening was employed to identify children at risk of developing conduct disorder. The procedure proved to be a valid predictor of conduct disorder among subjects. Variables found to contribute to a higher risk of developing conduct disorder include poor family communication and involvement, poor maternal coping skills and an external parent locus of control.

Abstract Event-related fMRI was used to dissociate the neural systems involved in category learning with and without awareness. Ten subjects performed a speeded response category learning task. Functional MR images [...]

Theories of the regulation of cognition suggest a system with two necessary components: one to implement control and another to monitor performance and signal when adjustments in control are needed. Event-related functional magnetic resonance imaging and a task-switching version of the Stroop task were used to examine whether these components of cognitive control have distinct neural bases in the human brain. A double dissociation was found. During task preparation, the left dorsolateral prefrontal cortex (Brodmann's area 9) was more active for color naming than for word reading, consistent with a role in the implementation of control. In contrast, the anterior cingulate cortex (Brodmann's areas 24 and 32) was more active when responding to incongruent stimuli, consistent with a role in performance monitoring., Cognitive control has long attracted the attention of philosophers and psychologists interested in how the human brain carries out the higher functions of awareness, memory, and language. The concept of [...]

This commentary challenges Rogers & McClelland (R&M) to use their model to account for delusional belief formation and maintenance. The gradual development of delusions and the nature of disconnectivity in Capgras delusions are used to illustrate the role of emotional salience in delusions. It is not clear how this kind of emotional saliency can be represented within the current architecture.

This commentary challenges the authors to use their computational modeling techniques to support one of their central claims: that schizophrenic deficits in bottom-up (Gestalt-type tasks) and top-down (cognitive control tasks) context processing tasks arise from the same dysfunction. Further clarification about the limits of cognitive coordination would also strengthen the hypothesis.