A 15-year longitudinal test of the theory of planned behaviour to predict physical activity in a randomized national sample of Canadian adults

BackgroundThere have been very limited long-term prospective studies examining social-cognitive models in the PA domain with large, representative population samples.ObjectiveThe primary objective was to examine the Theory of Planned Behaviour's (TPB) ability to explain PA behaviour in a randomly selected national sample of Canadian adults over a 15-year period. A secondary objective was to test the moderating effects of gender on TPB.DesignThe study employed a longitudinal design.MethodsA cohort of 1427 randomly-selected adults reported TPB constructs and PA behaviour in 1988, and again in 2003. Structural equation modelling techniques were employed to test TPB.ResultsThe full model including both 1988 and 2003 TPB measures accounted for 29% and 21% of the variance in intention, and 9% and 22% of the variance in PA in 1988 and 2003, respectively. Gender moderated aspects of the TPB in the full model. The core predictive model (1988 TPB constructs predicting 2003 PA behaviour) explained 13% of the variance in 2003 PA behaviour.ConclusionsThe TPB's long-term ability to predict PA behaviour is modest.     

Explaining the justice-performance relationship: trust as exchange deepener or trust as uncertainty reducer?

Past research has revealed significant relationships between organizational justice dimensions and job performance, and trust is thought to be one mediator of those relationships. However, trust has been positioned in justice theorizing in 2 different ways, either as an indicator of the depth of an exchange relationship or as a variable that reflects levels of work-related uncertainty. Moreover, trust scholars distinguish between multiple forms of trust, including affect- and cognition-based trust, and it remains unclear which form is most relevant to justice effects. To explore these issues, we built and tested a more comprehensive model of trust mediation in which procedural, interpersonal, and distributive justice predicted affect- and cognition-based trust, with those trust forms predicting both exchange- and uncertainty-based mechanisms. The results of a field study in a hospital system revealed that the trust variables did indeed mediate the relationships between the organizational justice dimensions and job performance, with affect-based trust driving exchange-based mediation and cognition-based trust driving uncertainty-based mediation.     

Contraction intensity and velocity on vastus lateralis SEMG power spectrum and amplitude

Effect of contraction intensity [100%, 75%, 50%, and 25% maximum voluntary contraction (MVC)] and movement velocity [0 degrees (isometric)], 50 degrees, 100 degrees, 200 degrees, and 400 degrees/sec. [isovelocities]) on root mean square amplitude (SEMG-RMS) and median frequency power spectrum (SEMG-MNF) of vastus lateralis (VL) surface electromyography was investigated with ten healthy female university students. Peak torque (PT), mean torque (MT), SEMG-MNF, and SEMG-RMS, analyzed using separate repeated-measures analyses of variance (p < or = .05), indicated: (1) an inverse relation between PT and MT and movement velocity, (2) greater SEMG-MNF values during all isovelocity conditions compared with isometric conditions, with highest values occurring at 50 degrees /sec. and at 100% and 75% MVC, and (3) at all contraction intensities SEMG-RMS values were higher during dynamic movements than isometric movements and highest at 200 degrees /sec. Isovelocity contractions were inferred to facilitate a greater recruitment of fast-twitch fibers (via increased SEMG-MNF), which was intensified at 50 degrees /sec., whereas greater overall muscle activation was found at 200 degrees /sec.     

Is artefactualness a value-relevant property of living things?

Artefacts are often regarded as being mere things that possess only instrumental value. In contrast, living entities (or some subset of them) are often regarded as possessing some form of intrinsic (or non-instrumental) value. Moreover, in some cases they are thought to possess such value precisely because they are natural (i.e., non-artefactual). However, living artefacts are certainly possible, and they may soon be actual. It is therefore necessary to consider whether such entities should be regarded as mere things (like most non-living artefacts) or as possessing intrinsic value (like many, if not all) living entities. That is, it is necessary to determine whether artefactualness is a value-relevant property with respect to the intrinsic value of living things.     

Minimal mimicry: Mere effector matching induces preference

Both mimicking and being mimicked induces preference for a target. The present experiments investigate the minimal sufficient conditions for this mimicry-preference link to occur. We argue that mere effector matching between one’s own and the other person’s movement is sufficient to induce preference, independent of which movement is actually performed. In Experiments 1 and 2, participants moved either their arms or legs, and watched avatars that moved either their arms or legs, respectively, without any instructions to mimic. The executed movements themselves and their pace were completely different between participants (fast circular movements) and targets (slow linear movements). Participants preferred avatars that moved the same body part as they did over avatars that moved a different body part. In Experiment 3, using human targets and differently paced movements, movement similarity was manipulated in addition to effector overlap (moving forward–backward or sideways with arms or legs, respectively). Only effector matching, but not movement matching, influenced preference ratings. These findings suggest that mere effector overlap is sufficient to trigger preference by mimicry.     

From racial discrimination to risky sex: prospective relations involving peers and parents

This study investigated how early experience with racial discrimination affected the subsequent risky sexual behaviors of a diverse sample of African American youths (N = 745). The analyses focused on 3 risk-promoting factors thought to mediate the hypothesized discrimination → risky sex relation: negative affect, affiliation with deviant peers, and favorable attitudes toward risky sex. In addition, attentive parenting was examined as a protective factor. Analyses using structural equation modeling revealed that youths who perceived more racial discrimination at age 10 or 11 were engaging in more sexual risk taking at age 18 or 19. This relation was mediated by the hypothesized risk-promoting factors via pathways that were consistent with our conceptual model. Results also indicated a prospective reciprocal relation between parenting and children's deviant affiliations: deviant peer affiliations at age 10 or 11 predicted more attentive parenting behaviors by the parents; this response from the parents, in turn, predicted relatively fewer deviant affiliations when the youths were 15 or 16. Study findings are discussed in terms of their relevance to the disproportionately high rates of sexually transmitted infections among African Americans.     

Predicting others’ actions: evidence for a constant time delay in action simulation

Recent evidence indicates that humans can precisely predict the outcome of occluded actions. It has been suggested that these predictions arise from a mental simulation which might run in real-time. The present experiments aimed to specify the time course of this simulation process. Participants watched transiently occluded point-light actions and the temporal outcome after occlusion was manipulated. Participants were instructed to judge the temporal coherence of the action after a short (Experiment 1) and a long occlusion period (Experiment 2). Both experiments revealed a comparable negative point of subjective equality (PSE), indicating that action simulation took constantly longer than the observed action itself. Such a temporal error was not present when inverted actions were used, (Experiment 3) ruling out a pure visually driven effect. The results suggest that the temporal error is due to costs arising from a switch from action perception to an internal simulation process involving motor representations.     

Movement kinematics affect action prediction: comparing human to non-human point-light actions

The influence of movement kinematics on the accuracy of predicting the time course of another individual's actions was studied. A human point-light shape was animated with human movement (natural condition) and with artificial movement that was more uniform regarding velocity profiles and trajectories (artificial condition). During brief occlusions, the participants predicted the actions in order to judge after occlusion whether the actions were continued coherently in time or shifted to an earlier or later frame. Error rates and reaction times were increased in the artificial compared to the natural condition. The findings suggest a perceptual advantage for movement with a human velocity profile, corresponding to the notion of a close interaction between observed and executed movement. The results are discussed in the framework of the simulation account and alternative interpretations are provided on the basis of correlations between the velocity profiles of natural and artificial movements with prediction performance.     

What is more important for national well-being: money or autonomy? A meta-analysis of well-being, burnout, and anxiety across 63 societies

What is more important: to provide citizens with more money or with more autonomy for their subjective well-being? In the current meta-analysis, the authors examined national levels of well-being on the basis of lack of psychological health, anxiety, and stress measures. Data are available for 63 countries, with a total sample of 420,599 individuals. Using a 3-level variance-known model, the authors found that individualism was a consistently better predictor than wealth, after controlling for measurement, sample, and temporal variations. Despite some emerging nonlinear trends and interactions between wealth and individualism, the overall pattern strongly suggests that greater individualism is consistently associated with more well-being. Wealth may influence well-being only via its effect on individualism. Implications of the findings for well-being research and applications are outlined.