Context-processing deficits in schizophrenia: diagnostic specificity, 4-week course,and relationships to clinical symptoms

Previous research on schizophrenia suggests that context-processing disturbances are one of the core cognitive deficits present in schizophia. 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.     

Using video modeling and reinforcement to teach perspective-taking skills to children with autism

We evaluated video modeling and reinforcement for teaching perspective-taking skills to 3 children with autism using a multiple baseline design. Video modeling and reinforcement were effective; however, only 2 children were able to pass an untrained task, indicating limited generalization. The findings suggest that video modeling may be an effective technology for teaching perspective taking if researchers can continue to develop strategies for enhancing the generalization of these new skills.     

Latent change models of adult cognition: are changes in processing speed and working memory associated with changes in episodic memory?

The authors used 6-year longitudinal data from the Victoria Longitudinal Study (VLS) to investigate individual differences in amount of episodic memory change. Latent change models revealed reliable individual differences in cognitive change. Changes in episodic memory were significantly correlated with changes in other cognitive variables, including speed and working memory. A structural equation model for the latent change scores showed that changes in speed and working memory predicted changes in episodic memory, as expected by processing resource theory. However, these effects were best modeled as being mediated by changes in induction and fact retrieval. Dissociations were detected between cross-sectional ability correlations and longitudinal changes. Shuffling the tasks used to define the Working Memory latent variable altered patterns of change correlations.     

Assessing working memory and language comprehension in Alzheimer's disease.

Studies of language impairments in patients with Alzheimer's disease have often assumed that impairments in linguistic working memory underlie comprehension deficits. Assessment of this hypothesis has been hindered both by vagueness of key terms such as "working memory" and by limitations of available working memory tasks, in that many such tasks either seem to have little relationship to language comprehension or are too confusing or difficult for Alzheimer's patients. Four experiments investigated the usefulness of digit ordering, a new task assessing linguistic working memory and/or language processing skill, in normal adults and patients with probable Alzheimer's disease. The digit ordering task was shown to be strongly correlated with the degree of dementia in Alzheimer's patients. The task correlated with measures of language processing on which patients and normal controls performed differently. The results are interpreted as indicating that linguistic representations, linguistic processing, and linguistic working memory are intertwined, such that a deficit of one (e.g., working memory) cannot be said to "cause" a deficit in the other. The implications of this approach are explored in terms of task demands in comprehension and memory measures, and interpretation of previous results in the literature.     

Adolescent Substance Use: Preliminary Examinations of School and Neighborhood Context

In considering the influences of microsystems on adolescent substance use, familial and peer contexts have received the most extensive attention in the research literature. School and neighborhood settings, however, are other developmental contexts that may exert specific influences on adolescent substance use. In many instances, school settings are organized to provide educational services to students who share similar educational abilities and behavioral repertoires. The resulting segregation of students into these settings may result in different school norms for substance use. Similarly, neighborhood resources, including models for substance use and drug sales involvement, may play an important role in adolescent substance use. We briefly review literature examining contextual influences on adolescent substance use, and present results from two preliminary studies examining the contribution of school and neighborhood context to adolescent substance use. In the first investigation, we examine the impact of familial, peer, and school contexts on adolescent substance use. Respondents were 283 students (ages 13 to 18) from regular and special education classrooms in six schools. Although peer and parental contexts were important predictors of substance use, school norms for drug use accounted for variance in adolescent use beyond that explained by peer and parental norms. Data from a second study of 114 adolescents (mean age = 15) examines neighborhood contributions to adolescent substance use. In this sample, neighborhood indices did not contribute to our understanding of adolescent substance use. Implications for prevention are presented.     

The Mozart Effect: An Artifact of Preference

The "Mozart effect" reported by Rauscher, Shaw, and Ky (1993, 1995) indicates that spatial-temporal abilities are enhanced after listening to music composed by Mozart. We replicated and extended the effect in Experiment 1: Performance on a spatial-temporal task was better after participants listened to a piece composed by Mozart or by Schubert than after they sat in silence. In Experiment 2, the advantage for the music condition disappeared when the control condition consisted of a narrated story instead of silence. Rather, performance was a function of listeners' preference (music or story), with better performance following the preferred condition.     

Do novel associative word stem completion and cued recall share the same memory retrieval processes?

The aim of this study was to determine whether word stem completion for novel associations between cue and target words was mediated by automatic unconscious memory processes or effortful memory processes under conscious control. This was done by applying full and divided attention conditions at test to stem completion, cued recall, and recognition, and by administering a questionnaire that probed the memory strategies used by subjects during the completion test. Divided attention had no effect on stem completion performance, but did reduce associative cued recall. Recognition performance was weakened overall by divided attention, but the associative effect was similar under both attention conditions. This suggested that novel associative word stem completion was mediated by automatic retrieval processes. However, the results of the questionnaire indicated that only subjects who attempted to remember the words from the study phase during the completion task showed any novel associative effect. It is concluded that novel association word stem completion and cued recall share automatic retrieval processes, which nevertheless give rise to the experience of remembering.     

Gravity biases in a non-human primate?

Pre-school children expect falling objects to travel in a straight line even when there are clear physical mechanisms that deviate the object's path (Hood, 1995). The current study set out to determine whether this expectancy is limited to humans. Cotton-top tamarins (Saguinus oedipus oedipus), a New World monkey species, were tested on Hood's (1995) experimental task where objects are dropped down a chimney connected by an opaque tube to one of three containers. Like human children, there was a significant tendency to search in the container underneath the chimney where the food was dropped on the first trial, even though aligned chimneys and containers were never connected. These search errors suggest that there may be a gravity bias that operates when both primate species fail to understand the constraints operating on object trajectories. Unlike human children however, tamarins were generally more likely to perseverate in making errors even though repeated testing and cost incentives were used.