Bayesian Diagnostics of Hidden Markov Structural Equation Models with Missing Data

Cocaine is a type of drug that functions to increase the availability of the neurotransmitter dopamine in the brain. However, cocaine dependence or abuse is highly related to an increased risk of psychiatric disorders and deficits in cognitive performance, attention, and decision-making abilities. Given the chronic and persistent features of drug addiction, the progression of abstaining from cocaine often evolves across several states, such as addiction to, moderate dependence on, and swearing off cocaine. Hidden Markov models (HMMs) are well suited to the characterization of longitudinal data in terms of a set of unobservable states, and have increasingly been used to uncover the dynamic heterogeneity in progressive diseases or activities. However, the existence of outliers or influential points may misidentify the hidden states and distort the associated inference. In this study, we develop a Bayesian local influence procedure for HMMs with latent variables in the presence of missing data. The proposed model enables us to investigate the dynamic heterogeneity of multivariate longitudinal data, reveal how the interrelationships among latent variables change from one state to another, and simultaneously conduct statistical diagnosis for the given data, model assumptions, and prior inputs. We apply the proposed procedure to analyze a dataset collected by the UCLA center for advancing longitudinal drug abuse research. Several outliers or influential points that seriously influence estimation results are identified and removed. The proposed procedure also discovers the effects of treatment and individuals’ psychological problems on cocaine use behavior and delineates their dynamic changes across the cocaine-addiction states.     

类别性空间记忆右侧化优势及其受威胁情境的影响

以往研究发现类别空间关系表征具有左半球激活优势,但在行为表现中是否存在对侧化的右侧化优势尚且不明确。本研究采用两个被试内实验,探讨空间记忆的行为表现是否具有右侧化优势以及这种优势是否受威胁情境的影响。实验1被试学习完一幅模拟地图中物体位置关系后进行相对位置判断任务,结果发现了显著的空间行为反应右侧化优势。实验2使被试在威胁情境中完成相同任务,发现右侧化优势消失。实验表明类别性空间记忆的行为表现具有右侧化优势,且具有情境不稳定性,这为空间记忆的偏侧化研究提供了一定的行为实验证据。     

结构方程在心理学研究中的应用

近年来,在教育、社会及心理学等研究领域,结构方程模型(SEM,Structural Equation Modeling)已成为重要的多变量分析方法,并日益受到广大研究者的重视。本文旨在对SEM作简要概述,并讨论其在心理学研究中的应用,以及在应用过程中应该遵循的标准和需要注意的一些问题。     

留学经验与艺术创造力

采用两个艺术创造力测量任务比较了中国留学生、德国大学生和中国国内学生的艺术创造力水平。使用共感评价技术作为评判艺术作品创造程度、技术水平等维度的方法。研究发现:(1)在艺术创造力任务中,中国留学生没有表现出比中国国内学生的优势,说明可能多元文化经验对创造力表达的影响是有条件的;(2)德国学生的艺术创造力水平高于中国学生,本结果支持前人研究中有关个人主义文化相对于集体主义文化更有助于创造力表达的相关假设;(3)共感评价技术是艺术创造力研究的有效工具。     

数学学习困难初中生的中央执行系统特点

为揭示数学学习困难学生的认知过程加工特点,筛选上海111名初中生（男生46名,女生68名,平均年龄11.97岁）比较数学困难学生（55名）与数学优秀学生（56名）的中央执行系统的表现差异,通过反应停止任务和Flanker任务考察抑制能力以及注意控制能力。结果发现各种抑制和注意控制条件下,数困组学生的正确率低于数优组;在具有干扰的情况的成绩更能有效预测数学成绩;中央执行系统能力在初中总体具有上升发展趋势,数困生的发展具有波动性。因此,数学学习困难在中央执行系统中的缺损主要是对抗干扰的能力不足,而非简单的加工速度。     

我国中等职业学校青少年学生情感素质的现状

本研究采用自编的《青少年情感素质调查问卷》对全国3类地区9大城市1767名中等职业学校青少年学生进行了问卷调查。结果表明：我国中职生情感素质总体处于积极正向、亟待提高的状况;女生的情感素质稍优于男生,但存在结构性差异;情感素质与中职生学业自评呈正相关;居住情况和父母学历对中职生情感素质影响不大;与同龄高中生在情感总体上没有显著差异,仅理智情感发展低于高中生,并主要表现在自信感和好奇心方面;师生关系良好、教师有情施教对中职生各方面情感素质发展具有极为重要的促进作用,应引起教育部门的高度关注。     

数学学习困难初中生的N-back任务表现特征

目的：分析数学学习困难初中生与学习优秀初中生的核心认知过程机制差异。方法：采用N-back任务作为测查工作记忆能力的指标,分析初中42名数困生和53名数优生的表现差异。结果：两组学生在0-back任务中无显著差异,在1-back和2-back任务中的差异逐渐增大。回归分析表明2-back和1-back任务对数学成绩有显著影响。结论：1）随着认知负荷增高,数困生和数优生的表现差距增大。数学学习困难的核心认知缺损是工作记忆能力而非简单认知加工过程。2）N-back任务能有效预测数学学习成绩。     

Generalized full-information item bifactor analysis

Full-information item bifactor analysis is an important statistical method in psychological and educational measurement. Current methods are limited to single-group analysis and inflexible in the types of item response models supported. We propose a flexible multiple-group item bifactor analysis framework that supports a variety of multidimensional item response theory models for an arbitrary mixing of dichotomous, ordinal, and nominal items. The extended item bifactor model also enables the estimation of latent variable means and variances when data from more than 1 group are present. Generalized user-defined parameter restrictions are permitted within or across groups. We derive an efficient full-information maximum marginal likelihood estimator. Our estimation method achieves substantial computational savings by extending Gibbons and Hedeker's (1992) bifactor dimension reduction method so that the optimization of the marginal log-likelihood requires only 2-dimensional integration regardless of the dimensionality of the latent variables. We use simulation studies to demonstrate the flexibility and accuracy of the proposed methods. We apply the model to study cross-country differences, including differential item functioning, using data from a large international education survey on mathematics literacy.     

Colateralization of Broca's area and the visual word form area in left-handers: fMRI evidence

Language production has been found to be lateralized in the left hemisphere (LH) for 95% of right-handed people and about 75% of left-handers. The prevalence of atypical right hemispheric (RH) or bilateral lateralization for reading and colateralization of production with word reading laterality has never been tested in a large sample. In this study, we scanned 57 left-handers who had previously been identified as being clearly left (N = 30), bilateral (N = 7) or clearly right (N = 20) dominant for speech on the basis of fMRI activity in the inferior frontal gyrus (pars opercularis/pars triangularis) during a silent word generation task. They were asked to perform a lexical decision task, in which words were contrasted against checkerboards, to test the lateralization of reading in the ventral occipitotemporal region. Lateralization indices for both tasks correlated significantly (r = 0.59). The majority of subjects showed most activity during lexical decision in the hemisphere that was identified as their word production dominant hemisphere. However, more than half of the sample (N = 31) had bilateral activity for the lexical decision task without a clear dominant role for either the LH or RH, and three showed a crossed frontotemporal lateralization pattern. These findings have consequences for neurobiological models relating phonological and orthographic processes, and for lateralization measurements for clinical purposes.