Effects of student pairing and public review on physical activity during school recess

The purpose of this study was to evaluate the effects of student pairing and feedback during recess on children's step counts. During baseline, participants wore a sealed pedometer during recess. During intervention, we paired participants with higher step counts with participants with lower step counts. We encouraged teams to compete for the highest step count each day and provided feedback on their performance during each recess session. Results showed a large mean increase in step count from baseline to intervention. These results suggest that children's steps during recess can be increased with a simple and cost‐effective intervention.     

Prediction of calcaneal bone competence from biomechanical accommodation variables measured during weighted walking

Carrying weight while walking is a common activity associated with increased musculoskeletal loading, but not all individuals accommodate to the weight in the same way. Different accommodation strategies could lead to different skeletal forces, stimuli for bone adaptation and ultimately bone competence. The purpose of the study was to explore the relationships between calcaneal bone competence and biomechanical accommodation variables measured during weighted walking. Twenty healthy men and women (10 each; age 27.8 ± 6.8 years) walked on a treadmill at 1.34 m/s while carrying 0, 44.5 and 89 N weights with two hands in front of the body. Peak vertical ground reaction force and sagittal plane angular displacements of the trunk and left lower extremity during weight acceptance were measured and used to quantify accommodation. Calcaneal bone stiffness index T-score (BST) was measured using quantitative ultrasound. Correlation and stepwise multiple regression were used to predict calcaneal BST from the accommodation variables. Accommodations of the foot and ankle explained 29 and 54% (p ≤ .015) of the variance in calcaneal BST in different regression models. Statistical resampling using 1000 replications confirmed the strength and consistency of relationships, with the best model explaining 94% of the variance in calcaneal BST. Individuals who change foot and ankle function when carrying heavier weight likely alter the control of gravitational and muscular forces, thereby affecting calcaneal loading, bone adaptation and bone competence. These novel findings illustrate the importance of gait accommodation strategies and highlight a potential clinical consequence that requires further investigation.     

Do kinematic metrics of walking balance adapt to perturbed optical flow?

Visual (i.e., optical flow) perturbations can be used to study balance control and balance deficits. However, it remains unclear whether walking balance control adapts to such perturbations over time. Our purpose was to investigate the propensity for visuomotor adaptation in walking balance control using prolonged exposure to optical flow perturbations. Ten subjects (age: 25.4 ± 3.8 years) walked on a treadmill while watching a speed-matched virtual hallway with and without continuous mediolateral optical flow perturbations of three different amplitudes. Each of three perturbation trials consisted of 8 min of prolonged exposure followed by 1 min of unperturbed walking. Using 3D motion capture, we analyzed changes in foot placement kinematics and mediolateral sacrum motion. At their onset, perturbations elicited wider and shorter steps, alluding to a more cautious, general anticipatory balance control strategy. As perturbations continued, foot placement tended toward values seen during unperturbed walking while step width variability and mediolateral sacrum motion concurrently increased. Our findings suggest that subjects progressively shifted from a general anticipatory balance control strategy to a reactive, task-specific strategy using step-to-step adjustments. Prolonged exposure to optical flow perturbations may have clinical utility to reinforce reactive, task-specific balance control through training.     

4～6岁幼儿经济博弈中的信任行为及其影响因素

本研究通过两个实验考察幼儿是否在博弈任务中表现出对陌生人的信任行为,同时考察可能对幼儿的信任产生影响的因素,包括个体认知因素(观点采择)和环境因素(负性反馈和代际传递)。研究对189名4~6岁幼儿及其家长进行多种任务的测量。实验一通过修订Evans和Krugger(2011)的信任博弈任务,考察幼儿在匿名信任博弈中的信任行为,结果发现与4岁幼儿相比,6岁幼儿对他人的信任更低;实验二考察了幼儿信任的影响因素,结果发现,幼儿在得到负性反馈结果后再次进行信任博弈任务时,他们对他人的信任比前次有所降低,6岁幼儿对他人返还数量的预期比4岁幼儿下降程度更大;6岁幼儿的信任行为(第一次给出意愿)与观点采择能力显著相关;6岁幼儿的信任水平与家长的信任水平显著相关。     

情绪感染的发生机制

原始性情绪感染理论认为, 情绪感染是一个“情绪觉察-无意识模仿-生理反馈-情绪体验”的过程, 情绪感染是一个由生理诱发情绪的过程。早在1884年, 詹姆士和兰格就提出了情绪外周学说, 同样描述了从身体变化到情绪变化的关系路径, 但没有描述从刺激事件到外周身体变化的发生机制。对情绪感染的发生机制的研究能揭示这一“自下而上”的情绪产生机制。研究选取有效大学生被试62名, 参与下列研究：(1) 在眼动实验中使用情绪图片作为感官情绪信息, 以考察觉察者的情绪觉察水平。(2) 在生物反馈实验中, 使用仿真课堂教学视频作为感官情绪信息, 以考察觉察者的无意识模仿水平和生理反馈水平。使用路径分析证实了情绪感染的路径机制, 在真实情境的诱发下, 这种通过生理唤醒而诱发情绪的机制是可能的。     

Improving judgmental forecasts with judgmental bootstrapping and task feedback support

This study examines the utility of two widely advocated methods for supporting judgmental forecasts—providing task feedback and providing judgmental bootstrapping support. In a simulated laboratory based experiment that focused on producing composite sales forecasts from three individual components, we compared the effectiveness of these two methods in improving final judgmental forecasts. In the presence of cognitive feedback task, feedback led to better forecasts than providing judgmental bootstrap forecasts. Simply providing bootstrap forecasts was of no additional benefit over a control condition. This was true in terms of the Brunswik Lens model measures of achievement, knowledge, and consistency, and in terms of forecast accuracy. This occurred both in stable environments and when special events (unusual one‐time events requiring adjustments to the forecasts) arose. Copyright © 2005 John Wiley & Sons, Ltd.     

Learning in the brain–computer interface: insights about degrees of freedom and degeneracy from a landscape model of motor learning

In this paper, we examine the role of degrees of freedom and their degeneracy in learning in the brain–computer interface paradigm. Though the traditional notion of degrees of freedom in motor learning gave emphasis to muscle and joint activity, the broader concept of dimensions of behavior is relevant to brain–computer interface learning where there is no muscle activity. The role of degeneracy in the dimensions of brain activity is proposed to enhance learning through robustness to stability loss and adaptability in the search for new stable states. Principles for the application of augmented information for learning to coordinate and control the degenerate degrees of freedom in the brain–computer interface are outlined.     

De‐escalation after repeated negative feedback: emergent expectations of failure

Research on willingness to make marginal investments (e.g., the escalation and sunk cost literatures) has often focused on project completion decisions, such as the “radar‐blank plane.” This paper discusses a fundamentally different type of marginal investment decision, that of couples deciding whether to continue infertility treatment in the face of repeated failures. Two experiments based on this context show that when people face multiple independent chances to achieve a valued goal but are unsure about chances of success, premature quitting or “de‐escalation” is the norm. Repeated negative feedback appears to induce individuals to see each successive failure as more and more diagnostic. As a result, even a short series of failed attempts evokes beliefs that future attempts will also fail. These emergent expectations of failure, generated by causal attribution processes, associative learning, and/or discounting of ambiguous information, appear very compelling and induce people to forgo profitable marginal investments. Copyright © 2004 John Wiley & Sons, Ltd.     

技术、主体与形而上学的玄学遐想

本文主要从科学、技术与社会(STS)的视角出发,通过对当今法国哲学家让·鲍德后期晦涩的哲学思想,特别是其命定策略的考察,阐发了鲍德里亚后期哲学的重要意义:(1)鲍德里亚后期思想是一种典型的悲观的技术决定论;是现代技术决定论的翻版。(2)鲍德里亚的后期思想是对近代理性哲学的颠覆和“反动”,它试图通过对技术与人的关系的思辨考察,消解近代理性哲学中的大写的主体的“人”,并给出了未来技术社会中一幅悲观可怕的“人”的命运的图画。(3)后形而上学的玄学则是鲍德里亚思想的最终归宿。鲍德里亚后期思想既有其悲观主义的极端倾向,也包含了深刻的哲理,需要处于信息社会的我们加以关注。