Shifting from implicit to explicit knowledge: different roles of early- and late-night sleep

Sleep has been shown to promote the generation of explicit knowledge as indicated by the gain of insight into previously unrecognized task regularities. Here, we explored whether this generation of explicit knowledge depends on pre-sleep implicit knowledge, and specified the differential roles of slow-wave sleep (SWS) vs. rapid eye movement (REM) sleep in this process. Implicit and explicit knowledge (insight) related to a hidden regularity were assessed in an associative motor-learning task (number reduction task, NRT), which was performed in two sessions (initial practice and retest) separated by 3 h of either early-night sleep, rich in SWS, or of late-night sleep, rich in REM sleep. About half of the participants developed signs of implicit rule knowledge (i.e., speeded reaction times for responses determined by the hidden regularity) at initial practice preceding early or late sleep. Of these, half developed explicit knowledge across early-night sleep, significantly more than across late-night sleep. In contrast, late-night subjects preferentially remained on the level of implicit rule knowledge after sleep. Participants who did not develop implicit knowledge before sleep had comparable rates of transition to implicit or explicit knowledge across early and late sleep. If subjects gained explicit knowledge across sleep, this was associated with lower amounts of REM sleep, specifically in the late-night group. SWS predominant during the early night may restructure implicit memory representations in a way that allows creating an explicit representation afterward, whereas REM sleep in the late night appears to stabilize them in their implicit form.     

The neural correlates of reward-related trial-and-error learning: an fMRI study with a probabilistic learning task

This fMRI study investigated the neural correlates of reward-related trial-and-error learning in association with changing degrees of stimulus-outcome predictabilities. We found that decreasing predictability was associated with increasing activation in a frontoparietal network. Only maximum predictability was associated with signal decreases across the learning process. The receipt of monetary reward revealed activation in the striatum and associated frontoparietal regions. Present data indicate that during reward-related learning, high uncertainty forces areas relevant for cognitive control to remain activated. In contrast, learning on the basis of predictable stimulus-outcome associations enables the brain to reduce resources in association with the processes of prediction.     

Peace psychology for a peaceful world

Although the literature in peace psychology has been growing rapidly, many American psychologists are unaware of how conflict is resolved and peace is conceptualized and achieved. This article reviews the long history and broadening scope of peace psychology and introduces a model of peace that is useful for organizing the literature. The model suggests that peace can be facilitated at four different points of intervention. The authors discuss relationships between positive and negative peace, structural and direct violence, and peacekeeping, peacemaking, and peacebuilding. They advance some challenges for peace psychologists and conclude that peace psychology is a crucial field for grappling with humanity's most pressing problems in the coming decades. (PsycINFO Database Record (c) 2008 APA, all rights reserved).     

Gesturing makes learning last

The gestures children spontaneously produce when explaining a task predict whether they will subsequently learn that task. Why? Gesture might simply reflect a child's readiness to learn a particular task. Alternatively, gesture might itself play a role in learning the task. To investigate these alternatives, we experimentally manipulated children's gesture during instruction in a new mathematical concept. We found that requiring children to gesture while learning the new concept helped them retain the knowledge they had gained during instruction. In contrast, requiring children to speak, but not gesture, while learning the concept had no effect on solidifying learning. Gesturing can thus play a causal role in learning, perhaps by giving learners an alternative, embodied way of representing new ideas. We may be able to improve children's learning just by encouraging them to move their hands.     

Life satisfaction shows terminal decline in old age: longitudinal evidence from the German Socio-Economic Panel Study (SOEP)

Longitudinal data spanning 22 years, obtained from deceased participants of the German Socio-Economic Panel Study (SOEP; N = 1,637; 70- to 100-year-olds), were used to examine if and how life satisfaction exhibits terminal decline at the end of life. Changes in life satisfaction were more strongly associated with distance to death than with distance from birth (chronological age). Multiphase growth models were used to identify a transition point about 4 years prior to death where the prototypical rate of decline in life satisfaction tripled from -0.64 to -1.94 T-score units per year. Further individual-level analyses suggest that individuals dying at older ages spend more years in the terminal periods of life satisfaction decline than individuals dying at earlier ages. Overall, the evidence suggests that late-life changes in aspects of well-being are driven by mortality-related mechanisms and characterized by terminal decline.     

Positive and Negative Affectivity and Facet Satisfaction: A Meta-analysis

Although several studies have investigated the dispositional approach to global job satisfaction, less direct attention has been given to the relationship between dispositions and facet satisfaction. The current meta-analysis examined the relationships of trait positive affectivity (PA) and trait negative affectivity (NA) with satisfaction toward the following five job facets: work itself, supervision, co-workers, pay and promotion. In general, results suggested the presence of a dispositional component to facet satisfaction. Moderator analyses examined whether the strength of these relationships depended on the particular scales used to assess dispositions.     

Organizational identification and organizational commitment: Distinct aspects of two related concepts

The conceptual differences between organizational commitment and identification are discussed theoretically and examined empirically. The present study is based on data of 450 employees of five different organizations in Nepal. A revised eight-item scale was designed out of Cheney's Organizational Identification Questionnaire to assess the core aspects of organizational identification. In confirmatory factor analyses, identification was found to be distinguishable from four related commitment concepts (i.e. affective, continuance, normative, and attitudinal commitment).