Demonstrating and eliminating the aggregation effect in physical skill tasks

Confidence judgments can be elicited in multiple ways. One of these procedures is to provide confidence judgments regarding each of a number of cases (individual judgments). A second procedure is to provide confidence judgments about a set of items (an aggregate judgment). Much research has demonstrated an aggregation effect—that individual judgments are more confident than aggregate judgments—within the cognitive knowledge domain. However, this effect has not previously been investigated with physical performance skill tasks. In three experiments, participants gave individual and aggregate judgments regarding the number of successful tosses they would make in either a ring toss, ping‐pong toss, or basketball toss task. In keeping with the aggregation effect, individual judgments were more confident than were aggregate judgments of success. Additionally, we eliminated the aggregation effect in Experiments 2 and 3 by employing a case‐specific base rate manipulation. Consistent with previous research with cognitive tasks, these results suggest that individual confidence judgments for physical skill tasks are determined primarily by characteristics associated with the individual case to be judged, whereas aggregate confidence judgments are determined by a more general evaluation of one's ability in the domain. Copyright © 2009 John Wiley & Sons, Ltd.     

Distinct modes of executing movement sequences: reacting, associating, and chunking

Responding to individual key-specific stimuli in entirely unfamiliar keying sequences is said to involve a reaction mode. With practice, short keying sequences can be executed in the chunking mode. This is indicated by the first stimulus sufficing for rapid execution of the entire sequence. The present study explored whether an associative mode develops also in participants who practice short keying sequences. This associative mode would involve priming by earlier events of responses to external stimuli, and is believed to be responsible for skill in the Serial Reaction Time task. In the present study participants practiced two discrete 6-key sequences. In the ensuing test phase, participants were prevented from using the chunking mode by including two deviant stimuli in most sequences. The results from the remaining - unchanged - familiar sequences confirmed that participants no longer used the chunking mode, but as predicted by associative learning these sequences were executed faster than unfamiliar sequences.     

Effect of Sensory Deprivation on Maximal Force Abilities from Local to Non-local Digits

Abstract

The present study investigates the effect of sensory deprivation of the index and middle finger on motor function of all digits during maximal voluntary force production tasks. A total of 27 subjects performed maximal isometric pressing tasks by using different instructed finger combinations. Subjects completed the same tasks in two visits: a control visit when they had normal sensory feedback in all fingers, and an anesthesia visit when digital nerve blocks were performed on their right index and middle fingers. We evaluated three aspects of motor adaptation on both local (anesthetized) and non-local (non-anesthetized) digits during maximal force production: (1) task-relevant and overall force magnitude, (2) force directional application, and (3) digital individuation and force sharing. Our results indicate that selective digital anesthesia resulted in decreased maximal force magnitude, changed direction of force production, and significant changes extended to non-local digits. The motor weakness and inefficiency revealed in the non-local digits implies that sensory information from each digit can be shared across the digits to assist motor execution within the same hand.     

Sequential dependencies in driving

The effect of recent experience on current behavior has been studied extensively in simple laboratory tasks. We explore the nature of sequential effects in the more naturalistic setting of automobile driving. Driving is a safety-critical task in which delayed response times may have severe consequences. Using a realistic driving simulator, we find significant sequential effects in pedal-press response times that depend on the history of recent stimuli and responses. Response times are slowed up to 100 ms in particular cases, a delay that has dangerous practical consequences. Further, we observe a significant number of history-related pedal misapplications, which have recently been noted as a cause for concern in the automotive safety community. By anticipating these consequences of sequential context, driver assistance systems could mitigate the effects of performance degradations and thus critically improve driver safety.     

IMAGINATIVE CONTAGION

Abstract: The aim of this article is to expand the diet of examples considered in philosophical discussions of imagination and pretense, and to offer some preliminary observations about what we might learn about the nature of imagination as a result. The article presents a number of cases involving imaginative contagion: cases where merely imagining or pretending that P has effects that we would expect only perceiving or believing that P to have. Examples are offered that involve visual imagery, motor imagery, fictional emotions, and social priming. It is suggested that imaginative contagion is a more prevalent phenomenon than has typically been recognized.     

Effects of Fencing Training on Motor Performance and Asymmetry Vary With Handedness

Abstract

Previous studies showed that motor asymmetries are reduced in left-handers and after a long-term fencing training in right-handers. Interestingly, left-handed athletes are substantially over-represented in elite fencing. These findings have been speculatively explained by imbalance in experience of fighting opposite handedness opponents resulted from skewed distribution of handedness, i.e. lefties encounter more righties than righties encounter lefties. Whereas these assumptions could be accurate, the underlying mechanisms remain ambiguous. In this study, we investigated effects of fencing training on motor performance and asymmetry with respect to handedness. We compared fencing performance of left- and right-handed fencers in both training and combat conditions. In the combat condition, left-handers won seven out of twelve matches consisted of twelve bouts each. They also showed a significantly longer hit detection time, a measure indicating better quality of fencing attack. In the training condition, left-handed fencers completed fencing board tests significantly faster than right-handers. These findings provide additional factor of superior motor performance to be considered when interpreting over-representation of lefties in elite fencing. Furthermore, our left-handers were less lateralized, which could explain that superior motor performance. This idea is consistent with previous findings of reduced asymmetry in right-handed fencers when comparing to non-athletes.     

精诚合一:医学哲学事业的永恒主题

医学哲学事业的价值在于发现并弘扬医学的基本精神。“精诚合一”是医学亘古不变的基本精神。当代医学哲学研究的任务是揭示医学的“精诚合一”特征及其深刻内涵,注重“精”与“诚”的有机结合,批判现实医疗活动和理论研究在“精”、“诚”问题上的片面,弘扬医学的基本精神。     

运动区Beta节律的活动特点及功能意义

人类大脑运动皮质的Beta(15~30 Hz)和Mu节律(8~14 Hz)有共同的活动特征,研究指出二者可能是联合的脑电成分。然而越来越多研究表明运动区Beta节律可能独立于Mu节律,且具有特殊的功能意义。线索诱发的Beta节律降低、运动前Beta节律降低和运动后Beta节律回复增强都是Beta与Mu节律不同的活动形式,表明运动区Beta节律有其独特的心理意义。本文主要对运动区Beta节律不同于Mu节律的活动特征及已有的理论解释进行了梳理和分析,并结合儿童研究的数据,从发展的角度对运动后Beta节律的理论假说进行了评述,最后在此基础上为进一步探索运动区Beta节律的功能意义提出了研究的展望。     

左侧背外侧前额叶在程序性运动学习中的作用

程序性运动学习包括序列学习和随机学习。神经影像学研究表明背外侧前额叶皮层(DLPFC)和初级运动皮层(M1)在程序性运动学习中发挥重要作用,但DLPFC和M1之间的联通性及其与不同程序性运动学习的关系尚不明确。本研究采用连续反应时间任务,结合经颅磁刺激(TMS)方法,探讨左侧DLPFC到M1的联通性在不同程序性运动学习中的差异。实验1采用两连发TMS探测DLPFC到M1的最佳投射时间点;实验2,被试分为2组,分别进行序列学习和随机学习,在学习前、后采集行为学数据,以及M1的运动诱发电位和DLPFC-M1联通性的电生理学数据。行为学结果发现序列学习组的学习效果更佳;电生理学结果发现,两组被试学习前、后M1的运动诱发电位均未发生改变;在最佳时间投射点、适当刺激强度下,序列学习组DLPFC-M1联通性发生改变,且与学习成绩相关,而随机学习组没有改变。结果说明DLPFC到M1的联通性增强可能是序列学习成绩更佳的重要原因,这一结果从电生理角度为DLPFC在运动学习中的作用提供了重要证据。     

隐性知识的具身机制、转化与管理

隐性知识是知识经济时代的发展关键,在多个学科的知识体系中占有重要位置。由于隐性知识有内隐表征、主观经验和情境性等多种跨层属性,导致管理学、体育学等学科面临隐性知识转化与管理的难题。隐性知识本质上是具身性的,身体经验与情境的互动为个体在知识系统中归纳与形成隐性知识提供了基础。隐性知识的提取与应用机制为组织对隐性知识的转化与管理提供了桥梁,而隐性知识的具身机制是其提取与应用的依据。本文将基于具身认知理论,结合多个学科的研究证据,对不同情境下的隐性知识提取与应用机制进行分析,旨在梳理出隐性知识的具身机制,并针对隐性知识的未来研究、转化与管理提出建议。