How many variables can humans process?

The conceptual complexity of problems was manipulated to probe the limits of human information processing capacity. Participants were asked to interpret graphically displayed statistical interactions. In such problems, all independent variables need to be considered together, so that decomposition into smaller subtasks is constrained, and thus the order of the interaction directly determines conceptual complexity. As the order of the interaction increases, the number of variables increases. Results showed a significant decline in accuracy and speed of solution from three-way to four-way interactions. Furthermore, performance on a five-way interaction was at chance level. These findings suggest that a structure defined on four variables is at the limit of human processing capacity.     

Psychological and stress hormone correlates in early life: a key to HPA-axis dysregulation and normalisation

Substantial recent research has focused on examining hormone indicators of psychosocial stress and on how relationships between stress and hormone changes might be linked to chronic illness. Particular attention has been paid to disease progression in cancer and HIV/AIDS. This focus has generated a plethora of research which has contributed both theoretically and clinically to the understanding of disease experience and the rate of disease progression. Measurement of salivary cortisol levels and diurnal variation has substantially advanced research methodology. Applying the unifying concept of allostasis and accumulated lifetime stress, this review attempts to assess the relevance of psychological and stress hormone correlates to disease resistance and health, through an examination of such correlates on the experience and outcomes of stress during childhood. Focus is on the role and importance of naturalistic social stress experiences such as school transition in healthy children, with emphasis on salivary cortisol as an endocrine marker of HPA-axis activation. It is argued that differing research perspectives offer valuable insight into the often assumed but largely unexplored links between early life experience and subsequent physical health outcomes in adulthood. Longitudinal studies incorporating measures of acute physical health outcome and of learning and memory are clearly needed.     

A psychometric comparison of the Beck Depression Inventory-II in English and Spanish

The Beck Depression Inventory-II (BDI-II; A. T. Beck, R. A. Steer, & G. K. Brown, 1996) is a widely used measure of depressive symptomatology originally authored in English and then translated to Spanish. However, there are very limited data available on the Spanish translation. This study compared the psychometric characteristics of the BDI-II in Spanish and English in a sample of 895 college students. The instrument was administered twice with a 1-week interval, either in the same language on both occasions or in a different language on each occasion. Results show strong internal consistency and good test-retest reliability in both languages. Confirmatory factor analysis demonstrated that the published English-language factor structure showed good fit with data from the Spanish instrument. Among bilingual participants who took the BDI-II in both languages, there was no significant language effect. These data provide initial evidence of comparable reliability and validity between the English and Spanish BDI-II in a nonclinical sample.     

Temporal references in dreams and autobiographical memory

In an attempt to determine whether temporal references identified in dreams follow the same temporal distributions as those documented for autobiographical memories, 28 younger women (18-35 years of age) and 30 older women (60-77 years of age) kept a home dream diary for 1 week and then slept 1 night in the laboratory for rapid eye movement sleep dream collection. The following morning, they identified temporal references in their dreams and produced a sample of autobiographical memories using the semantic cuing method. For both groups, there was a linear decrease in temporal references identified in dreams and autobiographical memories with increased remoteness for the last 30 years. As predicted, for the older group, there were similar cubic trends reflecting a disproportionately higher number of both temporal references identified in dreams and autobiographical memories from adolescence/early adulthood compared with adulthood and childhood. The results support the notion of continuity between waking and dreaming memory processes.     

Proximal Peer-Level Effects of a Small-Group Selected Prevention on Aggression in Elementary School Children: An Investigation of the Peer Contagion Hypothesis

Examined peer contagion in small group, selected prevention programming over one school year. Participants were boys and girls in grades 3 (46 groups, 285 students) and 6 (36 groups, 219 students) attending school in low-resource, inner city communities or moderate resource urban communities. Three-level hierarchical linear modeling (observations within individuals within groups) indicated that individual change in aggression over time related to the average aggression of others in the intervention group. The individual child was pulled toward peers mean level of aggression; so the intervention appeared to reduce aggression for those high on aggression, and to make those low on aggression more aggressive. Effects appeared to be magnified in either direction when the child was more discrepant from his or her peers. From these results we derive a principle of discrepancy-proportional peer-influence for small group intervention, and discuss the implications of this for aggregating aggressive children in small group programs.     

Timing during interruptions in timing

Duration and location of breaks in time interval production were manipulated in various conditions of stimulus presentation (Experiments 1-4). Produced intervals shortened and then stabilized as break duration lengthened, suggesting that participants used the break as a preparatory period to restart timing as quickly as possible at the end of the break. This interpretation was supported in Experiment 5, in which similar results were obtained with a reaction time response executed at the end of the break. In all experiments, produced intervals lengthened as the break occurred later during the interval. The authors conclude that varying break location and duration reveal, respectively, the influence of attentional time-sharing before the interruption and of preparatory processes taking place during the break.     

Reduced phonological similarity effects in patients with damage to the cerebellum

Ten cerebellar patients were compared to 10 control subjects on a verbal working memory task in which the phonological similarity of the words to be remembered and their modality of presentation were manipulated. Cerebellar patients demonstrated a reduction of the phonological similarity effect relative to controls. Further, this reduction did not depend systematically upon the presentation modality. These results first document that qualitative differences in verbal working memory may be observed following cerebellar damage, indicating altered cognitive processing, even though behavioral output as measured by the digit span may be within normal limits. However, the results also present problems for the hypothesis that the cerebellar role is specifically associated with articulatory rehearsal as conceptualized in the Baddeley-Hitch model of working memory.     

Contributions of response set and semantic relatedness to cross-modal Stroop-like picture-word interference in children and adults

Resistance to interference from irrelevant auditory stimuli undergoes development throughout childhood. To test whether semantic processes account for age-related changes in a Stroop-like picture-word interference effect, children (3- to 12-year-olds) and adults named pictures while listening to words varying in terms of semantic relatedness to the pictures and response set membership. In Experiments 1 and 2, with animal and clothing pictures, the interference effect observed in children, but not in adults, depended on the distractors' status as members of the response set. In Experiment 3, with unrelated pictures, adults, but not children, showed greater interference for trials with distractors in the response set. These results indicate developmental changes in picture-word interference involving the establishment of a response set in working memory.     

Premature mortality due to suicide, homicide, and motor vehicle accidents in health service delivery areas: comparison of status Indians in British Columbia, Canada, with all other residents

From each of 15 health regions, potential years of life lost (PYLL) before age 75 for Status Indians is compared for select causes of death with all other residents. Mortality data from 1991 to 2001 for rates of PYLL (standardized to the 1991 population) are from tables of the British Columbia Vital Statistics Agency and First Nations and Inuit Health Branch in 2002. PYLL rate differences and rate ratios were compared for two groups with significance of the former indicated by the 95% confidence interval. Overall, the rates of PYLL for suicide, homicide, and deaths due to motor vehicle accidents were about 224%, 340%, and 248% higher among Status Indians than all other residents. Rates of PYLL for homicide and deaths from motor vehicle accidents among Status Indian women exceeded those of other residents who were men. For suicide, Status Indian men ranked first and all other male residents of British Columbia ranked second.     

Response Mode Effects and Moral Values

In five studies, we measured the extent to which subjects weight moral product attributes in different response modes. We found that nonprice judgments such as likelihood of purchase ratings were more reflective of expressed moral attitudes than were pricing responses, and that holistic price evaluations were especially unlikely to reflect moral considerations. Post-task ratings confirmed the preference results, as did an experiment controlling for the influence of task goals. Our results have implications for compatibility theories of preference elicitation, the predictability of respondent ratings of attribute unacceptability, and the measurement of utilities for morally charged attributes.