Training-induced and electrically induced potentiation in the neocortex

Long-term potentiation (LTP) shares many properties with memory and is currently the most popular laboratory model of memory. Although it has not been proven that memory is based on an LTP-like mechanism, there is evidence that learning a motor skill can induce LTP-like effects. This evidence was obtained in a slice-preparation experiment, which precluded within-animal comparisons before and after training. In the present experiments, Long-Evans rats were unilaterally trained to acquire a forelimb reaching and grasping skill. Evoked potentials were found to be larger in motor cortex layer II/III in the trained, compared to the untrained, hemisphere in slice, acute, and chronic preparations. Consistent with previous research, the trained hemisphere was less amenable to subsequent LTP induction. Furthermore, the application of either LTP- or LTD-inducing stimulation during the training phase of the reaching task disrupted the acquisition of the skill, providing further evidence that memory may be based on an LTP mechanism.     

Study time effects in recognition memory

We empirically tested the assumption that study time increases recognition accuracy because the storage of information is better when study time is longer as Shiffrin and colleagues have reported, an assumption common to parallel models of recognition. In the present study with 123 subjects, we examined the effect of item strength on four measures: hit rate, false alarm rate, d', and beta, for a single-word recognition task with longer study times than those usually used in the literature. Analysis indicated significant increase for hit rate and d' and a decrease in false alarm rate, as one goes from weak to stronger study conditions, and a change in ln(beta) when study time is greater than 1 sec. These results suggest that familiarization is one, but not the only, factor underlying the strength-mirror effect.     

Is it culture or is it language? Examination of language effects in cross-cultural research on categorization

Differences in reasoning styles between Chinese and European Americans held even when controlling for the language of testing. Bilingual Chinese organized objects in a more relational and less categorical way than European Americans, whether tested in English or in Chinese. Thus, culture affects categorization independent of the testing language. Nevertheless, language affected some Chinese bilinguals' categorization. The responses of Chinese from the Mainland and Taiwan were more relational when tested in Chinese than when tested in English. Responses of Chinese from Hong Kong and Singapore were equally relational when tested in Chinese and in English. Age and context of learning English are discussed to explain the differential language effects among different Chinese groups. Theoretical and methodological implications are discussed.     

Identity and commitment in emergency teams

This paper adopts Tajfel's social identity theory perspective and applies it to the organizational context in order to study emergency intervention teams. Specifically, it is intended to explore the kind of social identification (professional, team, or organizational) prevalent among members of these organizations. It is intended, as well, to establish a clear distinction between two related, and often confused, concepts, i.e., organizational identification and commitment, and to discover which identification is more apt to predict the organizational outcomes of organizational citizenship behaviors and satisfaction. Our total sample consisted of 151 participants (firemen of the Madrid municipality and members of the army). It was found that organizational identification, as a kind of social identification, is different from organizational commitment, and that it is not its base nor one of its components, and that organizational identification, much as professional one, helps to explain peoples' behavior in organizations.     

Culture, control, and perception of relationships in the environment

East Asian cognition has been held to be relatively holistic; that is, attention is paid to the field as a whole. Western cognition, in contrast, has been held to be object focused and control oriented. In this study East Asians (mostly Chinese) and Americans were compared on detection of covariation and field dependence. The results showed the following: (a) Chinese participants reported stronger association between events, were more responsive to differences in covariation, and were more confident about their covariation judgments; (b) these cultural differences disappeared when participants believed they had some control over the covariation judgment task; (c) American participants made fewer mistakes on the Rod-and-Frame Test, indicating that they were less field dependent; (d) American performance and confidence, but not that of Asians, increased when participants were given manual control of the test. Possible origins of the perceptual differences are discussed.     

Regional grey matter volume in the posterior cingulate cortex predicts positive risk-taking: A moderation model

Positive risk-taking is a crucial element of individual creativity and social development. However, little is known regarding the relation between individual neural differences and positive risk-taking. In addition, critical thinking (CT) and gender have been proven to be two important individual-specific factors associated with risk-taking behaviour, and different levels of CT and gender may have diverse effects on the relationship between brain structure and positive risk-taking. The present study examined the relationship between positive risk-taking and regional grey matter volume (rGMV) in 292 healthy participants. The results showed that positive risk-taking was significantly positively associated with the rGMV of the posterior cingulate cortex (PCC). In addition, this study investigated individual differences in critical thinking and found that it moderated the relationship between rGMV and positive risk-taking. Individuals with lower CT had a stronger association between rGMV and positive risk-taking. Further analysis showed that for males, a greater rGMV was significantly linked to higher positive risk-taking tendency. These findings suggest that PCC evaluates risk and serves as a behavioural adaptation hub for positive risk-taking. This study thereby contributes to the literature on individual differences in brain structure and risk-taking by elucidating the moderating effects of CT and gender in healthy adults.     

Harold Garfinkel and Edward Rose in the early years of ethnomethodology

This article documents the beginning of the intellectual companionship between the founder of ethnomethodology, Harold Garfinkel, and Edward Rose, who is most often associated with his program of “ethno-inquiries.” I present results from archival research focusing on the contacts and collaborations between Rose and Garfinkel in the years 1955–1965. First, I describe the review process for Rose and Felton's paper, submitted to the American Sociological Review in 1955, which Garfinkel reviewed and after Rose's rebuttal recommended for publication. The paper induced Garfinkel to write an extensive commentary that has remained unpublished. Second, I discuss the 1958 New Mexico conference sponsored by the Air Force, which was an opportunity for Rose and Garfinkel to work together on topics related to common-sense knowledge and scientific knowledge. Third, I give an overview of the ethnomethodological conferences in 1962 and 1963, supported by an Air Force grant written collaboratively by Rose and Garfinkel. Here I focus primarily on Rose's research on “small languages,” which stimulated many discussions among the early ethnomethodologists. Rose's work and exchanges with Garfinkel demonstrate the former's affinity for miniaturization as a research approach and search for ways to empiricize topics of sociological theory in locally observable settings.     

语义的自动加工和选择性注意对Stroop效应的影响

本实验用正常人和聋哑人作被试进行比较,试图探讨语义的自动加工和选择性注意对Stroop效应的影响。将“红”“绿”“黄”“蓝”四个汉字中的每一个都用这四种颜色中的三种写成,然后按着事先排列好的顺序,分组呈现,并且在两种条件下分别要求被试延迟不同的时间进行反应,一种是刺激呈现前就告诉被试对“字”或“色”反应;另一种是刺激呈现后间隔不同的时间再向被试提出对“字”或“色”反应。实验结果发现,聋哑人和正常人在色—字干扰任务作业上没有明显的差异,说明语义的自动加工是一个普遍现象;而选择性注意能在很大的程度上改善被试的作业成绩,但颜色命名仍比字词反应困难;Stroop效应在延迟反应条件下发生变化,这种变化说明Stroop效应与记忆过程有联系。     

从汉字识别看视觉信息检测的整体优先性

本实验以汉字组成的复合汉字为材料研究了不同视角下辨别整体结构和辨别局部特性的反应时差异。实验发现,在正常情况下对整体的辨别反应时要显著低于对局部进行辨别的反应时,并且对象的不同大小对这种差异没有显著影响。这一结果表明整体和局部的“相对大小”不是造成反应时差异的主要原因,提示视觉信息检测是一个从大范围的整体到局部的过程,即存在整体优先性。实验还发现在作为局部的汉字和构成整体的复合字相同时,无论注意对象是局部还是整体,反应时均较不同时为小,这一结果表明整体和局部的作用是双向的。     

表象加工的容量和加工策略研究

本实验研究通过把汉字拆为其有机的组成成分,最少2个最多5个,在各成分顺序排列或随机排列两种条件下呈现给被试,要他们组合出原来汉字的方法对表象操作的容量和策略进行了初步的探讨。实验结果表明表象操作的容量是相当有限的,执行最优加工的容量为2—3个,上限约为4—5个。加工容量随操作复杂程度的高低可略有变化。结果还表明在本实验条件下系统对表象各成分的操作采取的是并行的同时加工,这种并行加工能大大提高表象加工的效率。