First,get your feet wet: The effects of learning from direct and indirect experience on team creativity

How does prior experience influence team creativity? We address this question by examining the effects of task experience acquired directly and task experience acquired vicariously from others on team creativity in a product-development task. Across three laboratory studies, we find that direct task experience leads to higher levels of team creativity and more divergent products than indirect task experience. Moreover, our results show that the difference in team creativity between direct and indirect task experience persists over time. Finally, our findings demonstrate that transactive memory systems fully mediate the effect of direct task experience on team creativity. Teams who acquired task experience directly are more creative because they develop better transactive memory systems than teams who acquired experience vicariously. We discuss how our findings contribute to understanding the effects of prior experience on team creativity, and the role of transactive memory systems in creative tasks.     

儿童2～4岁行为抑制的稳定性

采用实验室观察法研究了儿童行为抑制性发展的稳定性特征。被试为追踪样本,随机选取北京市124名儿童,经家长同意参加本项追踪项目。2岁时,有124名儿童参加本实验,在不同的陌生情景下对儿童行为进行录像观察,每次一对儿童和母亲。4岁时,有103名儿童参加实验室观察,21名儿童由于搬迁、失约或中途退出而没有数据;在观察室,每次邀请四名过完四岁生日不久的同龄、同性别、但父母评价害羞程度不同的、彼此陌生的儿童同时来到实验室作观察。结果表明：就整体而言,儿童在2岁时的行为抑制性特征与其4岁时的行为抑制性特征相关显著,但稳定性程度较低(0．294);通过对极端组和非极端组儿童的行为抑制性的稳定程度的比较发现,极端组儿童,无论是极端非抑制儿童还是极端抑制儿童,其行为特征的保持程度要好于非极端组;对儿童4岁时行为抑制性的性别差异检验虽然没有达到显著性水平(t＝-1．776,p＝0．079),但男孩总体上有非抑制性倾向(抑制性的平均分数为-0．2420),女孩有抑制性倾向(女孩的平均抑制性分数为0．2035)。     

3～4岁儿童攻击行为发展的追踪研究

对163名幼儿园小班儿童进行追踪观察,考察3-4岁期间儿童攻击行为的特点、发展模式及稳定性。主要获得以下结果：儿童最普遍的攻击形式是身体攻击．言语攻击和间接攻击的发生率较低;大多数攻击行为属于主动性攻击和工具性攻击;男孩的攻击行为总体上多于女孩．但女孩的间接攻击多于男孩;儿童的攻击性在3-4岁之间无显著变化,但敌意性攻击存在随年龄增长而增加的趋势;3-4岁儿童攻击性的个别差异已具有明显的稳定性。     

稳定性/发展性:气质研究视角的嬗变

气质作为心理学研究的一个重要领域,传统研究注重突出气质的先天性与稳定性,而近期研究则逐渐开始强调气质是具有行为基础的发展性的行为特征,表现出与传统研究不同的视角转向。目前这种“暗流涌动”式的转向将对气质研究领域的拓展和深化具有重要的导向意义。     

儿童行为抑制性发展的研究综述

美国心理学家杰罗姆·凯根提出了气质的行为抑制-非抑制性说,激发了学者从儿童的行为抑制性的角度对气质进行深入研究。本文阐述了当前行为抑制性研究对气质的研究方法的改进、行为抑制性发展的稳定性问题及抑制性与文化差异等的关系。     

Practical Reason and the Stability Standard

Practical reasoning, reasoning about what to do, is a very familiar activity. When we think about whether to cook or to go out for dinner, to buy a house or rent, or to study law or business, we are engaged in practical reasoning. If the kind of reasoning we engage in is truly a rational process, there must be some norms or standards that govern it; the process cannot be arbitrary or random. In this paper I argue that one of the standards that governs practical reasoning is the stability standard. The stability standard, I argue, is a norm that is constitutive of practical reasoning: insofar as we do not take violations of this norm to be relevant considerations, we do not count as engaged in reasoning at all. Furthermore, I argue that it is a standard we can explicitly employ in order to deliberate about our ends or desires themselves. Importantly, this standard will not require that some ends are prescribed or determined by reason alone. The stability standard, therefore, allows us to retain some of the attractive features of instrumentalism without accepting the implication that there is no rational way to evaluate ends.     

Do Older Adults and Those Recovered from Low Back Injury Share Common Muscle Activation Adaptations?

Theoretical models suggest trunk muscle activation compensates for spinal systems impairments. The purpose of this study was to determine if two populations (older adults and those recovered from a lower back injury (rLBI)) with spinal system impairments have similar muscle activation patterns to each other, but differ from controls. Trunk electromyograms collected from 12 older adults, 16 rLBI, and 19 controls during two dynamic tasks showed that older adults and rLBI had higher activation amplitudes, sustained temporal and more synergistic activation relative to controls. However, differences found between older adults and rLBI suggest that spinal system impairments differed between groups or that recent pain (rLBI) uniquely influenced muscle activation. This sheds light on our understanding of the relationship between spinal system impairments and muscle activation.     

Y-Balance Test Performance and Leg Muscle Activations of Children with Developmental Coordination Disorder

This study compared Lower Quarter Y-Balance Test (YBT-LQ) performance and leg muscle kinetics between children with and without developmental coordination disorder (DCD), and investigated the association between YBT-LQ performance and muscle kinetics in children with DCD. Forty-eight children with DCD and 51 children without DCD participated in the study. Leg muscle kinetics were measured using surface electromyography when performing YBT-LQ. Children with DCD exhibited an overall lower YBT-LQ scores than controls. They had a lower peak gastrocnemius medialis activation for YBT-LQ posteromedial direction and shorter duration for the muscle to reach peak torque for YBT-LQ anterior direction. No relationship was found between YBT-LQ performance and leg muscle activations in children with DCD. Children with DCD exhibited a less competent YBT-LQ performance with atypical neuromuscular control.     

Dynamic balance assessment during gait in children with Down and Prader-Willi syndromes using inertial sensors

Down (DS) and Prader-Willi (PWS) syndromes are chromosomal disorders both characterized by obesity, ligament laxity, and hypotonia, the latter associated with gait instability. Although these shared features may justify a common rehabilitation approach, evidence exists that adults with DS and PWS adopt different postural and walking strategies. The development of an instrumented protocol able to describe these strategies and quantify patients’ gait stability in the current clinical routine would be of great benefit for health professionals, allowing them to design personalized rehabilitation programs. This is particularly true for children with DS and PWS, where motor development is dramatically constrained by severe hypotonia and muscle weakness. The aim of this study was, thus, to propose an instrumented protocol, integrated with the clinical routine and based on the use of wearable inertial sensors, to assess gait stability in DS and PWS children.Fifteen children with DS, 11 children with PWS, and 12 typically developing children (CG) were involved in the study. Participants performed a 10-meter walking test while wearing four inertial sensors located at pelvis, sternum, and both distal tibiae levels. Spatiotemporal parameters (walking speed, stride frequency, and stride length) and a set of indices related to gait symmetry and upper-body stability (Root Mean Square, Attenuation Coefficient and Improved Harmonic Ratio) were estimated from pelvis and sternum accelerations. The Gross Motor Functional Measures (GMFM-88) and Intelligence Quotient (IQ Wechsler) were also assessed for each patient. A correlation analysis among the GMFM-88 and IQ scales and the estimated parameters was then performed.Children with DS and PWS exhibit reduced gait symmetry and higher accelerations at pelvis level than CG. While these accelerations are attenuated by about 40% at sternum level in CG and DS, PWS children display significant smaller attenuations, thus reporting reduced gait stability, most likely due to their typical “Trendelenburg gait”. Significant correlations were found between the estimated parameters and the GMFM-88 scale when considering the whole PWS and DS group and the PWS group alone.These results promote the adoption of wearable technology in clinical routines to monitor gait patterns in children with DS and PWS: the proposed protocol allows to markedly characterize patient-specific motor limitations even when clinical assessment scores provide similar results in terms of pathology severity. This protocol could be adopted to support health professionals in designing personalized treatments that, in turn, could help improving patients’ quality of life in terms of both physical and social perspectives.     

Anticipating ankle inversion perturbations during a single-leg drop landing alters ankle joint and impact kinetics

Anticipatory responses to inversion perturbations can prevent an accurate assessment of lateral ankle sprain mechanics when using injury simulations. Despite recent evidence of the anticipatory motor control strategies utilized during inversion perturbations, kinetic compensations during anticipated inversion perturbations are currently unknown. The purpose of this investigation was to examine the influence of anticipation to an inversion perturbation during a single-leg drop landing on ankle joint and impact kinetics. Fifteen young adults with no lateral ankle sprain history completed unanticipated and anticipated single-leg drop landings onto a 25° laterally inclined platform from a height of 30 cm. One-dimensional statistical parametric mapping (SPM) was used to analyze net ankle moments and ground reaction forces (GRF) during the first 150 ms post-landing, while peak GRFs, time to peak GRF, peak and average loading rates were compared using a dependent samples t-test (p ≤ 0.05). Results from the SPM analysis revealed significantly greater plantar flexion moment from 58 to 83 ms post-landing (p = 0.004; d = 0.64–0.77), inversion moment from 89 to 91 ms post-landing (p = 0.050; d = 0.58–0.60), and medial GRF from 62 to 97 ms post-landing (p < 0.001; d = 1.00–2.39) during the unanticipated landing condition. Moreover, significantly greater peak plantarflexion (p < 0.001; d = 1.10) and peak inversion moment (p = 0.007; d = 0.94), as well as greater peak (p = 0.002; d = 1.03) and average (p = 0.042; d = 0.66) medial loading rates, were found during the unanticipated landing condition. Our findings suggest alterations to ankle joint and impact kinetics occur during a single-leg drop landing when inversion perturbations are anticipated. Researchers and practitioners using drop-landings onto a tilted surface to assess lateral ankle sprain injury risk should consider implementing protocols that mitigate anticipatory responses.