Inferring the structure of latent class

Present optimization techniques in latent class analysis apply the expectation maximization algorithm or the Newton-Raphson algorithm for optimizing the parameter values of a prespecified model. These techniques can be used to find maximum likelihood estimates of the parameters, given the specified structure of the model, which is defined by the number of classes and, possibly, fixation and equality constraints. The model structure is usually chosen on theoretical grounds. A large variety of structurally different latent class models can be compared using goodness-of-fit indices of the chi-square family, Akaike’s information criterion, the Bayesian information criterion, and various other statistics. However, finding the optimal structure for a given goodness-of-fit index often requires a lengthy search in which all kinds of model structures are tested. Moreover, solutions may depend on the choice of initial values for the parameters. This article presents a new method by which one can simultaneously infer the model structure from the data and optimize the parameter values. The method consists of a genetic algorithm in which any goodness-of-fit index can be used as a fitness criterion. In a number of test cases in which data sets from the literature were used, it is shown that this method provides models that fit equally well as or better than the models suggested in the original articles.     

具体情绪及非依随反馈方式对自我妨碍的影响

该研究采用实验法考察了具体情绪以及非依随反馈方式对自我妨碍的影响。被试为104名大学生。结果表明：1）愉快组被试做出的决策型自我妨碍行为较少;恐惧组被试做出的回避型自我妨碍较多。2）两种非依随反馈方式对自我妨碍的影响没有显著差异。3）无论是决策型自我妨碍还是回避型自我妨碍,男生均高于女生。     

Very brief exposure II: the effects of unreportable stimuli on reducing phobic behavior

This experiment compared the effects of exposure to masked phobic stimuli at a very brief stimulus-onset asynchrony on spider-phobic and non-phobic individuals. Participants were identified through a widely used questionnaire and a Behavioral Avoidance Test (BAT) with a live, caged tarantula to establish baseline levels of avoidance. One week later, they were individually administered one of two continuous series of masked images: spiders or flowers. Preliminary masking experiments showed that independent samples of participants from the same populations failed to recognize these stimuli. Participants in the main experiment reported ratings of subjective distress immediately before and after the exposure manipulation. Then they engaged in the BAT once again. Very brief exposure to images of spiders reduced phobic participants' avoidance of the tarantula. No effects were evidenced on subjective distress, or on non-phobic participants. Theoretical implications for the non-conscious basis of fear are discussed.     

Nonlinear epigenetic variance: review and simulations

We present a review of empirical evidence that suggests that a substantial portion of phenotypic variance is due to nonlinear (epigenetic) processes during ontogenesis. The role of such processes as a source of phenotypic variance in human behaviour genetic studies is not fully appreciated. In addition to our review, we present simulation studies of nonlinear epigenetic variance using a computational model of neuronal network development. In each simulation study, time series for monozygotic and dizygotic twins were generated and analysed using conventional behaviour genetic modelling. In the results of these analyses, the nonlinear epigenetic variance was subsumed under the non-shared environmental component. As is commonly found in behaviour genetic studies, observed heritabilities and unique environmentabilities increased with time, whereas common environmentabilities decreased. The fact that the phenotypic effects of nonlinear epigenetic processes appear as unsystematic variance in conventional twin analyses complicates the identification and quantification of the ultimate genetic and environmental causes of individual differences. We believe that nonlinear dynamical system theories provide a challenging perspective on the development of individual differences, which may enrich behaviour genetic studies.     

General belief in a just world and resilience: Evidence from a collectivistic culture

Previous research showed that in the individualistic culture, adults endorse the personal more than the general belief in a just world (PBJW vs. GBJW). Comparatively little is known about the prevalence character and adaptive functions of GBJW, especially in the collectivistic culture. We conducted three surveys among the Chinese adults and adolescents. We found that (1) Chinese adults and adolescents endorsed more GBJW than PBJW; (2) Adult survivors with high exposure to post‐earthquake trauma and adolescents in the poverty‐stricken area maintained high GBJW, with relatively lower PBJW. (3) GBJW predicted the psychological resilience in all the three samples independent of PBJW. The results imply that in contrast to populations from the individualistic culture, people from the collectivistic culture endorse a robust GBJW, which allows them to resiliently confront harsh realities. Copyright © 2010 John Wiley & Sons, Ltd.     

Creative Scientific Problem Finding and Its Developmental Trend

This is a study of the development trend of creative scientific problem finding (CSPF) ability of a sample of 1,367 elementary, middle, and high school students in two Chinese cities. Students were instructed to generate science related questions in both open and closed conditions with responses scored for Fluency, Flexibility, and Originality. Results suggest that CSPF ability has a developmental trend characterized by a significant leap in the 5th grade, followed by a steady advance until it peaked in the 8th grade, and then declined and stabilized in the high school years (9th–11th grades). No difference between male and female students was found. The type of instruction showed significant differential influence on CSPF and its development.     

多动症儿童与认知事件相关电位的实验研究

本研究通过对29名多动症(MBD)儿童与正常儿童认知事件相关电位各成份的比较,结果发现多动症组与正常儿童组在反映大脑认知功能P300潜伏期有明显的差异,从而说明P300可以作为检测多动症儿童的参考性的客观指标。     

文本结构和时间应激对网页阅读绩效的影响

探讨了文本结构和时间应激对网页阅读绩效的影响效应。采用 2× 3被试间设计 ,自变量为文本结构和阅读时间 ,因变量为找到相关信息的时间及途径的额外节点数。结果发现 ,主效应及交互作用的影响均十分显著。其中 ,当阅读时间为 10和 2 0min时 ,超文本阅读的绩效均显著低于线性文本 ,而在 30min时两者无显著差异 ;对超文本 ,三种阅读时间的效应存在显著差异 ,而对线性材料 ,阅读时间的效应无显著差异。结论 :时间应激对超文本阅读绩效的影响更为明显     

再认条件下元监测判断的影响因素

探讨了再认条件下元监测判断的影响因素。以中文双字词对作为实验材料 ,安排在不同预先呈现时间、有无进行有意识记 ,以及不同识记遍数等条件下进行元监测判断。用计算机随机呈现项目 ,再认之前先让被试做元监测判断 ,判断是否是记过的项目的把握程度 ,再对有意识记过的项目做迫选再认 ,作为标准测验 ,以验证元监测判断的准确性。结果是预先呈现时间长、有意识记过的和识记遍数多的项目 ,对其再认的反应时较短 ,相应的元监测判断等级也较高 ;对只看而未有意记过的项目的判断是呈现时间长的判断等级反而低于呈现时间短的。此结果表明 ,再认条件下 ,元监测判断的等级的高低与识记项目的激活程度有关     

An evaluation of simultaneous and sequential presentation of preferred and nonpreferred food to treat food selectivity

In the current investigation, we compared two methods of food presentation (simultaneous vs. sequential) to increase consumption of nonpreferred food for 3 children with food selectivity. In the simultaneous condition, preferred foods were presented at the same time as nonpreferred food (e.g., a piece of broccoli was presented on a chip). In the sequential condition, acceptance of the nonpreferred food resulted in presentation of the preferred food. Increases in consumption occurred immediately during the simultaneous condition for 2 of the 3 participants. For 1 participant, increases in consumption occurred in the simultaneous condition relative to the sequential condition, but only after physical guidance and re-presentation were added to treatment. Finally, consumption increased for 1 participant in the sequential condition, but only after several sessions. These results are discussed in terms of possible mechanisms that may alter preferences for food (i.e., establishing operations, flavor-flavor conditioning).