The role of selective attention in visual awareness of stimulus features: Electrophysiological studies

Attention and awareness are closely related, but the nature of their relationship is unclear. The present study explores the timing and temporal evolution of their interaction with event-related potentials. The participants attended to specific conjunctions of spatial frequency and orientation in masked (unaware) and unmasked (aware) visual stimuli. A correlate of awareness appeared 100-200 msec from stimulus onset similarly to both attended and unattended features. Selection negativity (SN), a correlate of attentional selection, emerged in response to both masked and unmasked stimuli after 200 msec. This double dissociation between correlates of awareness and SN suggests that the electrophysiological processes associated with feature-based attentional selection and visual awareness of features can be dissociated from each other at early stages of processing. In a passive task, requiring no attention to the stimuli, early electrophysiological responses (before 200 msec) related to awareness were attenuated, suggesting that focal attention modulates visual awareness earlier than does selective feature-based attention.     

Impulsivity as a predictor of newly diagnosed depression

Depression is a severe mental disorder, whose onset has been related to environmental, genetic and personality factors. This study examined the association between impulsivity and incidence of depression. Logistic regression models were related to prospective data from two surveys (2-year time lag) conducted in a large cohort of hospital employees (N= 4,505). Only respondents with no history of depression at baseline were included. Impulsivity was predictive of the onset of depression (OR = 1.95, CI 95%= 1.28-2.97) after adjustment for age, sex and education. This association remained statistically significant after additional adjustment for a variety of baseline characteristics, such as smoking, alcohol consumption, and size of social network. A measure of mental distress (GHQ-12 responses), which may serve as a proxy measure for undiagnosed depression, was also associated with impulsivity. Impulsivity appears to be a distinct personality factor that may contribute to the onset of depressive illness in adults.     

When it is better to give than to receive: long-term health effects of perceived reciprocity in support exchange

The authors examined esteem enhancement theory and equity theory in explaining the long-term health status of men (n = 178) and women (n = 575). Baseline characteristics were measured in 1990-1993, intimate reciprocity in 1993, and recorded sickness absences for a 9-year period during 1993-2001. Among women, giving more support than receiving in intimate relationships positively affected subsequent health status, as indicated by fewer sickness absences. Among men, receiving more support than giving predicted fewer absences. These effects remained even after significant covariates were included in the model. Thus, women seem to benefit from giving support in intimate relationships, and men seem to benefit from receiving support in intimate relationships. The findings on women are in line with the esteem enhancement theory. No support was obtained for the equity theory.     

An examination of crossover and spillover effects of spousal and expatriate cross-cultural adjustment on expatriate outcomes

Integrating work-family and cross-cultural adjustment literatures, the researchers proposed and tested a spillover and crossover model of expatriates' cross-cultural adjustment with reciprocal relationships. Spillover effects refer to the influence that expatriate attitudes in a particular domain (e.g., work) have on attitudes in other domains (e.g., nonwork), whereas crossover effects refer to the influence of expatriate attitudes on the spouse's attitudes (and vice versa). Data collected from Japanese expatriates, their spouses, and their superiors strongly supported both spillover and crossover effects between expatriate and spousal cross-cultural adjustment. In addition, expatriates' cross-cultural adjustment was found to be related to satisfaction, which, in turn, was found to be negatively related to expatriates' intention to return to their homeland early.     

The organizing process of the American railroad business from an evolutionary perspective

The early organizing process of the American railroads could be periodized as follows: Railroad technology become perfected by the 1860s, the national network become perfected by the 1880s, and self‐sustaining railroad systems by the 1900s. The evolutionary path seems to be largely dictated by the “perfection” of stable configurations of “lower levels,” such as technological standards (e.g., uniform standard time). In the American railroads, on each level of activity there was a process of convergence, learning and coordination of pre‐existing components toward “equilibrium,” that allowed the emergence of new combinations, i.e. new levels of integration. Thus, convergent level‐specific process, i.e. the standardization and formalization of existing activities, was an essential step for radical process of divergence in the American railroads.     

Visual discrimination in an orangutan (Pongo pygmaeus): measuring visual preference

Although previous studies have confirmed that trained orangutans visually discriminate between mammals and artificial objects, whether orangutans without operant conditioning can discriminate remains unknown. The visual discrimination ability in an orangutan (Pongo pygmaeus) with no experience in operant learning was examined using measures of visual preference. Sixteen color photographs of inanimate objects and of mammals with four legs were randomly presented to an orangutan. The results showed that the mean looking time at photographs of mammals with four legs was longer than that for inanimate objects, suggesting that the orangutan discriminated mammals with four legs from inanimate objects. The results implied that orangutans who have not experienced operant conditioning may possess the ability to discriminate visually.     

Environmental enrichment protects against the effects of chronic stress on cognitive and morphological measures of hippocampal integrity

Chronic stress has detrimental effects on hippocampal integrity, while environmental enrichment (EE) has beneficial effects when initiated early in development. In this study, we investigated whether EE initiated in adulthood would mitigate chronic stress effects on cognitive function and hippocampal neuronal architecture, when EE started one week before chronic stress began, or two weeks after chronic stress onset. Adult male Sprague Dawley rats were chronically restrained (6h/d) or assigned as non-stressed controls and subdivided into EE or non-EE housing. After restraint ended, rats were tested on a radial arm water maze (RAWM) for 2-d to assess spatial learning and memory. The first study showed that when EE began prior to 3-weeks of chronic stress, EE attenuated chronic stress-induced impairments in acquisition, which corresponded with the prevention of chronic stress-induced reductions in CA3 apical dendritic length. A second study showed that when EE began 2-weeks after the onset of a 5-week stress regimen, EE blocked chronic stress-induced impairments in acquisition and retention at 1-h and 24-h delays. RAWM performance corresponded with CA3 apical dendritic complexity. Moreover, rats in EE housing (control or stress) exhibited similar corticosterone profiles across weeks, which differed from the muted corticosterone response to restraint by the chronically stressed pair-housed rats. These data support the interpretation that chronic stress and EE may act on similar mechanisms within the hippocampus, and that manipulation of these factors may yield new directions for optimizing brain integrity and resilience under chronic stress or stress related neuropsychological disorders in the adult.     

Psychological stress tasks in the prediction of blood pressure level and need for antihypertensive medication: 9-12 years of follow-up.

Increased blood pressure (BP) reactivity to subtypes of psychological stimuli may differentially predict the development of future BP elevation or hypertension. The authors present the 9-12-year follow-up results of 82 (86%) of 95 male participants with different BP levels. They were healthy, untreated, and age-matched volunteers from a routine health checkup carried out on all 35-, 40-, and 45-year-olds from a medium-sized city. Intra-arterial systolic blood pressure (SBP) during the psychological tasks improved the prediction of future casual SBP and noninvasive 24-hr ambulatory SBP compared with predictions from casual diagnostic measurements. Diastolic blood pressure (DBP) was very useful when added to casual DBP in predicting the need for antihypertensive medication. Reactivity to active tasks especially predicts the need for antihypertensive medication.