A New Procedure to Test Mediation With Missing Data Through Nonparametric Bootstrapping and Multiple Imputation

This article proposes a new procedure to test mediation with the presence of missing data by combining nonparametric bootstrapping with multiple imputation (MI). This procedure performs MI first and then bootstrapping for each imputed data set. The proposed procedure is more computationally efficient than the procedure that performs bootstrapping first and then MI for each bootstrap sample. The validity of the procedure is evaluated using a simulation study under different sample size, missing data mechanism, missing data proportion, and shape of distribution conditions. The result suggests that the proposed procedure performs comparably to the procedure that combines bootstrapping with full information maximum likelihood under most conditions. However, caution needs to be taken when using this procedure to handle missing not-at-random or nonnormal data.     

ADHD symptoms,academic achievement,self‐perception of academic competence and future orientation: A longitudinal study

In the investigation of the effect of attention deficit hyperactivity disorder (ADHD) symptoms on school careers there is a need to study the role of adolescent and childhood ADHD symptoms and academic achievement, and to incorporate measures that include the individual's perspective. Our aim was to gain an overview of the long‐term development of school careers in relation to ADHD symptoms. We studied associations between ADHD symptoms and academic achievement at different time‐points and future orientation at the end of high school, and assessed the role of self‐perceptions of academic competence in these associations. Participants were 192 children (47% girls) with a range of ADHD symptoms taken from a community sample. Collecting data at three time points, in 6th, 11th and 12th grade we tested a structural equation model. Results showed that ADHD symptoms in 6th grade negatively affected academic achievement concurrently and longitudinally. ADHD symptoms in 11th grade negatively affected concurrent academic achievement and academic self‐perception and future orientation in 12th grade. Academic achievement had a positive influence on academic self‐perception and future orientation. Given the other factors, self‐perception of academic competence did not contribute to outcomes. We concluded that early ADHD symptoms may cast long shadows on young people's academic progress. This happens mainly by way of stability in symptoms and relations to early low academic achievement.     

Longitudinal examination of the role of goal orientation in cross-cultural adjustment

In this longitudinal study, the authors introduced goal orientation theory to the study of cross-cultural adjustment. The authors examined relationships among dispositional goal orientation, domain-specific self-efficacy, and cross-cultural adjustment. Results indicated that a learning orientation was positively related to sojourners' academic and social self-efficacy, whereas a performance orientation was negatively related to sojourners' social self-efficacy. Sojourners' academic and social self-efficacy were positively related to academic and social adjustment, respectively. A learning orientation was positively related to academic and social adjustment, and the relationship was mediated by self-efficacy. A performance orientation was not related to adjustment. Finally, academic adjustment was positively related to grade point average. The authors discussed implications for research and practices.     

Perceived body size affected by garment and body mass index

This study investigated the effect of garment size on perceived body size. The perceived body sizes of nine Chinese men, with Body Mass Index between 17.0 and 37.1 kg/m(2), wearing five sizes of white T-shirts were assessed using Thompson and Gray's Nine-figural Scale. Garment sizes on perceived body sizes were different for those of different Body Mass Index. A backpropagation neural net model was used to model the nonlinear relationship between the perceived body size and the body's BMI, body chest girth, and garment ease (difference between garment and body chest girth). When the BMI was less than 20, wearing larger-sized T-shirts tended to increase perceived body size. For large chest sizes and for taller persons (BMI of 20 to 28) large garments made the wearer look thinner. However, for small persons (BMI of 20 to 28) effect of garment size was relatively small. Obese persons (BMI of > 28), wearing garments too tight or too loose were perceived as larger. Minimum perceived body size was found for garment ease of 2 to 3 cm.     

Behavioral expression of learned fear in rats is appropriate to their age at training,not their age at testing

Recent research has shown that learned fear emerges in a response-specific sequence. For example, an odor conditioned stimulus (CS) previously paired with shock elicits behavioral expressions of fear like avoidance at a younger age than it elicits other behavioral expressions of fear like potentiation of the startle response (Richardson, Paxinos, & Lee, 2000). In the present study, the question of whether learned fear is expressed in a manner appropriate to the animal's age at training or its age at testing was explored in three experiments, all using a within-subjects design. The results suggest that learned fear is expressed in a manner appropriate to the rat's age at training, not its age at testing. The Discussion section focuses on the implications of these findings for (1) the developmental analysis of memory and (2) the idea that an aversive CS elicits a central state of fear.     

Auditory abnormalities in autism: toward functional distinctions among findings

Recently, findings on a wide range of auditory abnormalities among individuals with autism have been reported. To date, functional distinctions among these varied findings are poorly established. Such distinctions should be of interest to clinicians and researchers alike given their potential therapeutic and experimental applications. This review suggests three general trends among these findings as a starting point for future analyses. First, studies of auditory perception of linguistic and social auditory stimuli among individuals with autism generally have found impaired perception versus normal controls. Such findings may correlate with impaired language and communication skills and social isolation observed among individuals with autism. Second, studies of auditory perception of pitch and music among individuals with autism generally have found enhanced perception versus normal controls. These findings may correlate with the restrictive and highly focused behaviors observed among individuals with autism. Third, findings on the auditory perception of non-linguistic, non-musical stimuli among autism patients resist any generalized conclusions. Ultimately, as some researchers have already suggested, the distinction between impaired global processing and enhanced local processing may prove useful in making sense of apparently discordant findings on auditory abnormalities among individuals with autism.     

Defensive pessimism and precautionary action during the COVID pandemic

The purpose of this research was to test, in the context of the COVID-19 pandemic, the hypothesis that individuals who use defensive pessimism as a strategy to manage anxiety are likely to act to prevent or mitigate negative outcomes. Across three crowd-sourced samples (Total N = 1416), defensive pessimism was correlated with self-reports of more precautionary behavior (Studies 1, 2, & 3) and fewer COVID-positive results (Study 3).     

Testing indirect effect with a complete or incomplete dichotomous mediator

Past methodological research on mediation analysis mainly focused on situations where all variables were complete and continuous. When issues of categorical data occur combined with missing data, more methodological considerations are involved. Specifically, appropriate decisions need to be made on estimation methods of the indirect effects and on confidence intervals for testing the indirect effects with accommodations of missing data. We compare strategies that address these issues based on a model with a dichotomous mediator, aiming to provide guidelines for researchers facing such challenges in practice.     

幼儿空间表征的初步实验研究

本实验分别从运动、照片和“地图”方面对4岁、5岁和6岁儿童在真实空间中的心理旋转及对参照信息的使用等空间表征的发展作了初步考察,结果发现,(1)运动部分客体定位最容易,“地图”部分其次,照片部分最难,(2)心理旋转能力在不同的实验方式下有不同的表现;(3)儿童的自我中心性反应也是相对的,并不一律依存于儿童的年龄,还与客观标记的作用有关。     

国内十个地区7—12岁儿童数学概念和运算能力发展的初步研究

本文综合了对我国十个地区959名7—12岁儿童的协作研究结果。探讨了儿童在认数、数序和系列、数的组成、运算和应用等四个方面的发展情况,并对儿童数学概念和运算能力发展中知识学习与数概念发展的关系、发展的过程、环境的影响、发展的阶段性等方面进行了讨论,也谈到了协作方法问题。