Influence of Strategy on Muscle Activity During Impact Movements

Participants (N = 10) made flexions or extensions about the elbow. Movements either were pointing (i.e., self-terminated) or terminated by impact on a barrier. The author examined how the trajectory and the electromyographic (EMG) patterns varied according to the distance moved, the instruction provided concerning speed, or the type of termination. Variations in kinematics induced by changes in the target distance or the instruction regarding speed were the same for impact and pointing movements. In comparison with a pointing movement of similar distance and speed instruction, an impact movement (a) accelerated longer and reached a higher velocity, (b) had a longer agonist EMG burst, and (c) had a low level of contraction that started slightly after the agonist burst and continued throughout the movement but had little or no antagonist burst. Because the different types of movements required different forces from the muscles, there were systematic, task-specific differences in EMG patterns that reflected task-specific differences in central control. The results of this experiment demonstrate that impact movements share some of the rules used in the control of other tasks, such as pointing and reversing movements. The sharing is not imposed by mechanical or physiological constraints but, rather, represents the imposition of internal constraints.     

Selection of variables in exploratory factor analysis: An empirical comparison of a stepwise and traditional approach

The purpose of this study was to investigate and compare the performance of a stepwise variable selection algorithm to traditional exploratory factor analysis. The Monte Carlo study included six factors in the design; the number of common factors; the number of variables explained by the common factors; the magnitude of factor loadings; the number of variables not explained by the common factors; the type of anomaly evidenced by the poorly explained variables; and sample size. The performance of the methods was evaluated in terms of selection and pattern accuracy, and bias and root mean squared error of the structure coefficients. Results indicate that the stepwise algorithm was generally ineffective at excluding anomalous variables from the factor model. The poor selection accuracy of the stepwise approach suggests that it should be avoided.     

“人体-环境”新系统医学模式探讨

运用系统论观点分析“生物-心理-社会”医学模式的优越性和局限性,提出以人为主体,将人作为一完整系统,人与环境合为大系统,以整体论的健康观为理念的“人体-环境”新系统医学模式,旨在更好地推动中西医结合和预防医学的发展,加速学科间的相互渗透,唤起健康和环保意识,以及更加重视政治和法律政策对现代医学的作用。     

Judgmental forecasting of univariate time series

To forecast numbers appearing in sequence, do people just take some sort of average of past items or do they use temporal pattern information that they have extracted from the sequence? In an experiment, subjects forecast successive numbers generated by a first-order auto regressive algorithm. Afterwards, they were asked to generate their own series of numbers to simulate the sequence they had been forecasting. It was found that (1) generation performance was good—subjects acquired an internal representation of the pattern in the sequence while forecasting it; (2) generation and forecasting performance were uncorrelated—this internal representation was not used for forecasting; (3) learnt ability to forecast a sequence did not transfer to another sequence that was of the same type but that subjects believed to come from another source; (4) subjects were good at estimating the probability that their forecasts would be correct but this ability declined with practice.     

Bug distribution and statistical pattern classification

A model (called the rule space model) which permits measuring cognitive skill acquisition, diagnosing cognitive errors, detecting the weaknesses and strengths of knowledge possessed by individuals was introduced earlier. This study further discusses the theoretical foundation of the model by introducing bug distribution and hypothesis testing (Bayes' decision rules for minimum errors) for classifying subjects into their most plausible latent state of knowledge. The model is illustrated with the domain of fraction arithmetic and compared with the results obtained from a conventional artificial intelligence approach.The authors would like to acknowledge Mr. Robert Baillie for developing several computer programs used for this research.This research was sponsored by the Personnel and Training Research Program, Psychological Sciences Division, Office of Naval Research.Some of the analyses presented in this report were performed on the PLATO® system. The PLATO® system is a development of the University of Illinois and PLATO® is a service mark of the Control Data Corporation.     

Empirical support for a Type A belief system

Much of the research on Type A behavior has focused on overt manifestations of the pattern; consequently, the underlying psychological dimensions are poorly understood (Matthews, 1982). Price (1982) has proposed an elaborate, but empirically unvalidated, model suggesting that a specific set of beliefs underlies the Type A behavior pattern. A series of experiments was conducted to test the validity of Price's model and to develop a device for assessing these beliefs. The internal consistency and test-retest reliability of this measure were .94 and .84, respectively. Significant positive correlations were found with traditional measures of Type A behavior as well as various facets of anger and anxiety. Finally, subjects who endorsed a high degree of Type A beliefs set significantly higher performance standards and were less likely to achieve these standards than their low-scoring counterparts. Results are discussed with regard to the theoretical construct of Type A as well as their implications for future research and treatment.This research is an extension of a study presented at the 92nd meeting of the American Psychological Association, Toronto, Canada, August 1984Special thanks to to Drs. James A. Blumenthal, Martin T. Gipson, Abby C. King, and Ellie T. Sturgis for their helpful comments in the preparation of this article.     

中小学生语文阅读能力结构的发展特点

本研究对小学六年级、初中三年级、高中三年级三个年龄切面的学生的阅读能力结构构成进行分析,揭示该能力结构的发统特点。结果表明,语文阅读能力结构随年龄的增长而发生变化。一方面表现为因素的数量逐步增加,另一方面表现为比较复杂、层次较高的因素在整个结构中的相对地位不断增强。研究结果进一步指出,该能力结构因素增加的实现方式不同于西方心理学界所认为的分解模式,而是表现为“接替”模式,亦即通过“基础能力因素”对活动的影响作用为新的因素所接替而实现。     

Ⅱ型糖尿病患者的行为特征研究

使用修订行为特征问卷调查了１１２名Ⅱ型糖尿病患者和１４７名健康对照组。结果表明： １．男性患者比健康人更加抑郁;２．女性患者比健康人更加焦虑、抑郁和愤怒;３．不论是男性 还是女性,此问卷可显著地区分这两组,越抑郁的人,越不焦虑的人,越缺少合理化这种心理 防御机制的人,越可能是糖尿病患者。结合其它的研究结果,认为存在着Ⅱ型糖尿病易感性 行为特征,主要表现为：高抑郁;低焦虑;对应激的唤醒水平低;不善于使用心理防御机制来 保护和伪装自己;寻找一些有趣的事情：回避痛苦事件;不善于延迟的满足,要求马上得到满 足;注意易分散等。     

Decision Pattern Analysis as a General Framework for Studying Individual Differences in Decision Making

This paper investigated decision pattern analysis (DPA) as a general and standard framework for studying individuals' consistent decision making behavior within and between contexts. DPA classifies decisions on the basis of judgement accuracy and the goal orientation of the decided‐upon action. Over repeated decisions, patterns of individuals' decision behavior are described by five variables: competence, optimality, recklessness, hesitancy and decisiveness. A fictitious medical decision making test and three standard cognitive ability tests (extended with confidence ratings and a ‘submit answer for marking’ decision) were used to investigate the psychometric properties of these DPA variables. Internal consistency of the decision patterns ranged from good to excellent. Convergent validity was assessed via cognitive abilities, metacognitive confidence and a control criterion imposed on confidence that determines the decision to be made: the point of sufficient certainty. Personality variables were included to assess discriminant validity. As hypothesised, cognitive abilities showed positive correlations with competence and optimality. High confidence, low points of sufficient certainty and a greater discrepancy between them were associated with higher decisiveness and recklessness, and lower hesitancy. Personality measures showed mixed and generally weak correlations with the DPA variables. These convergent and discriminant results also held after controlling for all variables in regression. The results provide preliminary psychometric support for DPA as a general framework of behavioral decision making. DPA has the potential to be exploited in many contexts for uses that, to date, have been unachievable in a psychometrically valid manner. Copyright © 2015 John Wiley & Sons, Ltd.