Nonconvergence,improper solutions,and starting values in lisrel maximum likelihood estimation

In the framework of a robustness study on maximum likelihood estimation with LISREL three types of problems are dealt with: nonconvergence, improper solutions, and choice of starting values. The purpose of the paper is to illustrate why and to what extent these problems are of importance for users of LISREL. The ways in which these issues may affect the design and conclusions of robustness research is also discussed.     

短时动作记忆的容量和精确度与动作学习的关系

该研究采用实验室实验法,被试自我报告分析及调查访问法,以三个年龄（１０岁、１４岁、１８岁）组学生及专项运动员为实验对象,揭示短时动作记忆的容量和精确度及其与动作学习指数的关系。结果表明：（１）被试的短时动作记忆容量为“５±２”,短时动作记忆的容量与动作学习的练习次数相联系;短时动作记忆的精确度与第一次动作练习的准确度相联系。（２）短时动作记忆的容量有随年龄增长而递增的趋势。（３）运动员与非运动员被试对于同类动作学习的练习次数存在显著性差异。     

Stress and memory: opposing effects of glucocorticoids on memory consolidation and memory retrieval

It is well established that glucocorticoid hormones, secreted by the adrenal cortex after a stressful event, influence cognitive performance. Some studies have found glucocorticoid-induced memory enhancement. However, many studies have reported impairing effects of glucocorticoids on memory function. This paper reviews recent findings from this laboratory on the acute effects of glucocorticoids in rats on specific memory phases, i.e., memory consolidation and memory retrieval. The evidence suggests that the consequences of glucocorticoid activation on cognition depend largely on the different memory phases investigated. Posttraining activation of glucocorticoid-sensitive pathways involving glucocorticoid receptors enhances memory consolidation in a pattern highly similar to that previously described for adrenal catecholamines. Also, similar to catecholamine effects on memory consolidation, glucocorticoid influences on memory consolidation depend on noradrenergic activation of the basolateral complex of the amygdala and interactions with other brain regions. By contrast, memory retrieval processes are usually impaired with high circulating levels of glucocorticoids or following infusions of glucocorticoid receptor agonists into the hippocampus. The hypothesis is proposed that these apparently dual effects of glucocorticoids on memory consolidation and memory retrieval might be related and that the basolateral complex of the amygdala is a key structure in a memory-modulatory system that regulates, in concert with other brain regions, stress and glucocorticoid effects on both memory consolidation and memory retrieval.     

From case management to prevention of scientific dishonesty in Denmark

In 1992, The Danish Medical Research Council established a national committee on scientific dishonesty with the twofold task of handling cases of scientific misconduct and taking preventive initiatives. Scientific dishonesty was proven in only five cases, but in another nine cases lesser degrees of deviations from good scientific practice were found. The experiences from a total of 24 treated cases indicated that three key areas were at the basis of most of the accusations and the deviations from good practice: uncertainty about 1) authorship, about 2) rights and duties to use scientific data and about 3) agreements at the initiation of joint studies. As a consequence guidelines on good practice have been issued on these key subjects. An earlier version of this paper was presented at a symposium, Scientific Misconduct. An International Perspective, organised by The Medical University of Warsaw, 16 November, 1998.     

Children's working memory: investigating performance limitations in complex span tasks

Three experiments investigated the roles of resource-sharing and intrinsic memory demands in complex working memory span performance in 7- and 9-year-olds. In Experiment 1, the processing complexity of arithmetic operations was varied under conditions in which processing times were equivalent. Memory span did not differ as a function of processing complexity. In Experiment 2, complex memory span was assessed under three conditions designed to vary both processing and intrinsic storage demands: mental arithmetic (significant attentional demands-requires storage), odd/even judgments (significant attentional demands-no storage required), and articulatory suppression (minimal attentional demands--no storage required). The highest memory spans were found in the articulatory suppression task. Span was at an intermediate level with arithmetic processing and was lowest for processing involving odd/even judgments. This difference in memory span for processing tasks involving arithmetic processing and odd/even judgments was eliminated in Experiment 3 when the pacing requirements of the arithmetic and odd/even processing tasks were equated. The results are consistent with the view that complex memory span performance is disrupted by processing activities that divert attentional resources from storage.     

智力落后儿童词汇语义记忆组织的实验研究

本研究采用类别概念例举法．对49名轻度智力落后儿童和49名智龄匹配的正常儿童以及22名实龄匹配的中度智力落后儿童进行了实验研究,旨在比较这三类儿童的心理词典中词的语义储存的区别。研究表明,轻度智力落后儿童与正常儿童的心理词典中词的语义储存有类似的组织结构．但在储存信息的数量上存在明显差异。轻度智力落后儿童的心理词典中储存同的组织较为松散,而且混杂了一些错误的信息;中度智力落后儿童储存有污的组织则更加松散,错误信息也更多,总之,正常儿童的心理词典中词的语义边界清晰,而智力落后儿童的语义边界模糊。     

前分类声音存储器对声调和情绪韵律的加工

采用系列位置回忆任务, 探讨作为声调语言的汉语普通话中声调及情绪信息是否具有近因及后缀效应, 从而揭示同为超音段信息的声调和情绪韵律在前分类声音存储器(Precategorical Acoustic Storage, PAS)中是否具有单独的表征, 及该表征可能受到哪些因素的影响。实验一和二分别考察了声调是否具有近因和后缀效应, 实验三和四分别考察了情绪信息是否具有近因和后缀效应。实验结果发现两者均在PAS存储器中有单独的表征, 但这种表征会受到一些因素的影响, 且受影响的方式不一样。研究结果表明作为超音段信息的声调和情绪信息在表征上的不稳定性和脆弱性, 及在短时记忆加工过程中的特殊性。     

视觉工作记忆中的加工与存储机制:回顾与思考

在视觉工作记忆的研究中,是否可能划分出视觉空间工作记忆和视觉物体工作记忆两个子系统还没有定论.子系统划分成立的基本前提是以特征为存储单位.当前关于存储单位的理论有特征理论、客体理论和双重存储等不同观点,多数视觉信息加工与存储机制的研究支持双重存储说.注意与视觉信息的加工和存储相互影响,因此,加工及存储机制的研究就要在具体的注意水平上进行.     

客体的视觉工作记忆研究进展

近年来,客体信息的视觉工作记忆问题引发了大量研究,并获得不少成果。本文对视觉工作记忆的研究范式,客体在视觉工作记忆中的存储方式、容量及保持时间等相关研究进行了概述,重点介绍关于视觉工作记忆存储单元和容量问题的"强客体"假设、"弱客体"假设和双重存储机制假设,并提出进一步的研究思路。