动态两难对策中信息反馈方式对合作行为的影响

本研究着重探讨了多人动态对策情景中信息反馈方式和群体认同度对合作行为变化的影响。结果表明,集体反馈比个人反馈更能促进被试的合作行为,而群体认同度对合作行为的影响不显著;在集体反馈条件下,合作行为在各轮次问的随机波动较大,但在三个决策阶段问较为稳定;个人反馈条件下,合作行为在各轮次问的随机波动较小,但在三阶段问呈现出不对称的“U”型变化趋势。研究认为,建立在反馈信息基础上的决策学习使合作行为的动态变化具有策略性和适应性。     

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.     

音乐对驾驶警觉的影响及其理论模型

驾车时听音乐非常普遍。唤醒理论认为, 音乐可以使驾驶员处于最佳唤醒水平, 有利于驾驶警觉的维持。但是, 根据中枢容量有限理论, 音乐也会使驾驶员分心, 危害道路安全。动态模型在已有研究的基础上提出, 音乐对驾驶警觉起到唤醒抑或分心影响, 取决于音乐复杂性、驾驶情境要求及驾驶员个体差异等诸多因素的动态调节。最新的补偿控制理论则强调, 驾驶员自我调控是恢复动态平衡的关键。而未来的研究应关注驾驶员心理负荷的测量、智能车载音乐系统的开发以及驾驶员培训等领域。     

项目分值对学习时间分配的影响：一种动态的过程

摘 要 研究考察了不同学习时段上,项目分值对学习时间分配的影响。结果发现: (1)分值的主效应显著,被试会选择更多的高分值项目学习, 且在高分值项目上分配更多的学习时间; (2)分值与学习时段存在交互作用,被试首先学习高分值项目,随后逐渐将学习重心转向中等分值项目,最后在临近测试前重点重学高分值项目。结果表明：学习时间分配是动态变化的,个体为了尽可能实现学习目标会在学习过程中不断调整所建构的议程。     

动态信息呈现对问题发现的影响研究

在多轮次动态和一次性静态两种呈现方式下,采用出声思维研究20名大学生潜藏与矛盾情境的问题发现特点。研究表明:(1)动态呈现促进被试更全面加工信息,发现问题数量和变通性优于静态呈现,但也阻断信息间的关联,不利于发现跨区问题。(2)动态呈现下,问题均匀分布在每个区域并按轮次先后顺序出现,静态呈现与此相反。(3)被试在新信息呈现后发现的问题分全新、改变方向、改变程度、一致性和联系性五类,潜藏情境中问题与先前信息关联更多。(4)被试对新信息影响做出积极评价。     

事件持续时间对情景模型更新的影响

采用移动窗口技术,探讨文本阅读中事件持续时间对情景模型更新的影响。实验1探讨不同的事件持续时间对情景模型更新进程的影响。结果发现,情景模型的更新受到事件持续时间的影响;实验2探讨在不同的事件持续时间条件下,情景模型的更新符合动态观还是静态观,结果支持了情景模型更新的动态观。该研究表明,事件持续时间与时间转换大小之间的关系对情景模型的更新起着重要的作用。同时,情景模型的更新符合动态观。     

Effect of Heel Heights on Female Postural Control During Standing on a Dynamic Support Surface With Sinusoidal Oscillations

The authors aimed to investigate female balance or stability control with comparative analysis of the center of pressure trajectory and plantar pressure distribution with different high-heeled shoes while standing on a dynamic surface with multidirectional perturbations. College females with at least 2 years' history of wearing high-heel shoes voluntarily participated in the test with a Novel Pedar insole (Novel, GmBH, Munich, Germany. With heels height increasing, the pressure time integral obviously transfer to the medial forefoot region, with center of pressure trajectory medially deviated significantly, either under anteroposterior or mediolateral perturbations. The passive plantarflexion position of ankle incurred by high heel increased the range of motion in the frontal plane but decreased ankle stability, thus increasing the challenge of body balance maintenance.     

Balance Performance During Perturbed Standing Is Not Associated With Muscle Strength and Power in Young Adults

The authors investigate the ways in which varied postural responses to translating platform perturbations are associated with the variables of strength and power. Twenty-four physically active and 27 sedentary young adults were exposed to a set of postural perturbations at varied velocities (10 and 20 cm/s) and the respective accelerations (6.4 and 6.9 m/s²), constant distance (6 cm), and 4 directions of platform motion (forward, backward, left-lateral, and right-lateral). They also performed maximum voluntary isometric contraction (MVC) and chair rising/chair jumping tests. The analysis of variance revealed significant interaction effect for peak center of pressure displacement, direction by velocity: F_3,129 = 24.43, p = .002; and direction by acceleration: F_3,129 = 34.18, p = .001. There were no significant correlations between peak center of pressure displacements and peak force and peak rate of force development measured during MVC in either standing (r = .27–57) or sitting positions (r = .12–51) and peak power during chair jumping (r = .47–.59) in all participants. As such, only a small proportion of variance was explained (9–39%, 3–23%, and 23–41%, respectively). In conclusion, interaction effects indicate that the composition of stimuli strongly influences compensatory responses and this effect is more pronounced in sedentary than in physically active young adults. Nevertheless, the dynamic balance is not associated with muscle strength and power in either group.     

Order-Constrained Solutions in <Emphasis Type="Italic">K</Emphasis>-Means Clustering: Even Better Than Being Globally Optimal

This paper proposes an order-constrained K-means cluster analysis strategy, and implements that strategy through an auxiliary quadratic assignment optimization heuristic that identifies an initial object order. A subsequent dynamic programming recursion is applied to optimally subdivide the object set subject to the order constraint. We show that although the usual K-means sum-of-squared-error criterion is not guaranteed to be minimal, a true underlying cluster structure may be more accurately recovered. Also, substantive interpretability seems generally improved when constrained solutions are considered. We illustrate the procedure with several data sets from the literature.