Gaussian variational estimation for multidimensional item response theory

Multidimensional item response theory (MIRT) is widely used in assessment and evaluation of educational and psychological tests. It models the individual response patterns by specifying a functional relationship between individuals' multiple latent traits and their responses to test items. One major challenge in parameter estimation in MIRT is that the likelihood involves intractable multidimensional integrals due to the latent variable structure. Various methods have been proposed that involve either direct numerical approximations to the integrals or Monte Carlo simulations. However, these methods are known to be computationally demanding in high dimensions and rely on sampling data points from a posterior distribution. We propose a new Gaussian variational expectation--maximization (GVEM) algorithm which adopts variational inference to approximate the intractable marginal likelihood by a computationally feasible lower bound. In addition, the proposed algorithm can be applied to assess the dimensionality of the latent traits in an exploratory analysis. Simulation studies are conducted to demonstrate the computational efficiency and estimation precision of the new GVEM algorithm compared to the popular alternative Metropolis–Hastings Robbins–Monro algorithm. In addition, theoretical results are presented to establish the consistency of the estimator from the new GVEM algorithm.     

Sibling relationships and civic engagement: A longitudinal study of Chinese young adults

This study examined the longitudinal associations of sibling intimacy and conflict with civic attitudes and behaviours among Chinese young adults. At two time points separated by about 12 months, questionnaire data were collected from 272 Chinese college students (mean age at Time 1 = 19.68 years; 69% female), students who studied in Hong Kong and had at least one sibling. Students rated their intimacy and conflict with their siblings and their parents at Time 1, and their civic attitudes and behaviours at both time points. Hierarchical regression revealed that, controlling for demographic characteristics and parent–child intimacy and conflict, sibling intimacy predicted increases in both civic attitudes and behaviours. Sibling conflict was a non-significant predictor, however. Findings highlighted the roles of siblings in understanding civic development in young adulthood and the utility of targeting sibling intimacy as means to foster young adults' positive attitudes to and active participation in civic activities.     

认知灵活性对概率类别学习的影响

本研究采用“数字-字母转换任务”区分高低认知灵活性者, 构建概率配对模式相同但形式不同的两个概率类别学习任务, 借助ERP技术探讨认知灵活性对概率类别学习任务的作用特点与机制。结果发现, 本研究的两个任务中, 高认知灵活性组的规则习得水平均优于低认知灵活性组, 认知灵活性能促进概率类别的学习。同时, 对不同学习阶段的ERPs分析结果显示, 高认知灵活性者在概率类别学习中的优势源于反馈加工过程。     

数字生态系统中创业机会的形成与发展：基于社会资本理论的探究

数字创业浪潮方兴未艾, 机会属性变化引起的数字创业机会形成与变化规律尚未被揭示。本研究以数字生态系统作为研究情境, 分析创业者利用数字生态系统可供性积累的社会资本, 如何影响创业机会形成与发展。从机会的合意性维度和内容维度两方面解释创业机会的变化规律, 考察创业者认知监控与新创企业数字化程度对这一路径的调节作用。本研究拓展社会资本理论在数字创业背景下的应用, 深化数字生态系统中的创业机会研究, 有助于指导创业者利用数字平台开展“破坏性创造”, 提升机会识别质量和效率, 促进创业生态系统建设。     

催产素影响恐惧习得和消退的认知神经机制

恐惧是一种基本的情绪, 在人类的生存和适应中发挥着重要作用。先前的研究表明, 杏仁核、背侧前扣带回、脑岛等脑区是条件化恐惧习得的认知神经基础, 杏仁核、海马和腹内侧前额叶等脑区在恐惧消退过程中发挥重要作用。研究发现, 催产素与恐惧习得和恐惧消退过程密切相关。恐惧习得过程中, 催产素影响杏仁核、背侧前扣带回的活动, 影响杏仁核与背侧前扣带回和脑干间的功能连接, 促进或抑制恐惧习得过程; 恐惧消退过程中, 催产素影响了杏仁核和腹内侧前额叶的活动, 并且影响杏仁核与内侧前额叶和海马间的功能连接, 促进或抑制恐惧消退过程。未来研究应从性别差异、神经网络模型、身心发育和病理研究等角度展开, 力图深入理解催产素影响恐惧情绪加工的认知神经机制。     

萌萌哒还是古灵精怪?奢侈品品牌可爱风格对消费者偏好的影响

奢侈品品牌热衷于使用可爱风格与消费者进行互动。本文以理想自我理论为基础,通过4个实验探索奢侈品品牌可爱风格类型对消费者偏好的影响机制和边界条件。实验1表明奢侈品品牌的可爱风格(婴儿图式/古灵精怪)会显著地影响消费者的品牌偏好,验证了主效应的因果链模型。实验2进一步明确了主效应的边界,结果表明品牌可爱风格对消费者偏好的影响只在奢侈品品牌的情境下才存在。实验3探索了自我监控水平对主效应的调节作用,发现对于低自我监控的个体,奢侈品品牌的可爱风格难以有效地影响品牌偏好。实验4分析了个体发展阶段对主效应的调节作用,结果表明对于成年期个体,古灵精怪可爱风格比婴儿图式可爱风格更能提高个体的奢侈品品牌偏好,对于童年期个体,婴儿图式可爱风格比古灵精怪可爱风格更易获得青睐。     

“医跑跑”事件折射出医学职业精神的制度性缺失

从深刻反思“医跑跑”事件入手,认为医学职业精神的制度性缺失是“医跑跑”出现的重要原因,并从目前许多医疗界制度医学职业精神的价值取向不高,医学职业精神制度供给不足,医学职业精神制度适应不强三方面的缺陷分析论证了医疗界制度必须强化医学职业精神,医学职业精神必须是制度内核,并提出相应建议.     

大型公立医院开展特需医疗服务的思考

随着生活水平的提高,人们的健康需求不断提高,有支付能力的人群不断增多.同时,特需医疗存在巨大的利润空间,使许多大型公立医院争相提供特需医疗服务.但是,大型公立医院作为特需医疗服务的提供主体存在许多的问题,要逐渐使大型公立医院分流,使营利性医院逐步成为特需医疗的主要提供主体.     

Combining CAT with cognitive diagnosis: A weighted item selection approach

Computerized adaptive testing (CAT) was originally proposed to measure θ, usually a latent trait, with greater precision by sequentially selecting items according to the student’s responses to previously administered items. Although the application of CAT is promising for many educational testing programs, most of the current CAT systems were not designed to provide diagnostic information. This article discusses item selection strategies specifically tailored for cognitive diagnostic tests. Our goal is to identify an effective item selection algorithm that not only estimates θ efficiently, but also classifies the student’s knowledge status α accurately. A single-stage item selection method with a dual purpose will be introduced. The main idea is to treat diagnostic criteria as constraints: Using the maximum priority index method to meet these constraints, the CAT system is able to generate cognitive diagnostic feedback in a fairly straightforward fashion. Different priority functions are proposed. Some of them are based on certain information measures, such as Kullback–Leibler information, and others utilize only the information provided by the Q-matrix. An extensive simulation study is conducted, and the results indicate that the information-based method not only yields higher classification rates for cognitive diagnosis, but also achieves more accurate θ estimation. Other constraint controls, such as item exposure rates, are also considered for all the competing methods.     

The integrated model of smartphone adoption: hedonic and utilitarian value perceptions of smartphones among korean college students

Abstract This study aims to propose an integrated model of smartphone adoption that incorporates social influences (SIs), perceived technicality, as well as hedonic and utilitarian attitudes into the technology acceptance model. The proposed model was empirically evaluated by using survey data collected from 239 Korean college students to investigate their perception and attitudes toward smartphone adoption intention. Our results show that users' attitudes and their adoption intention are highly influenced by SI and positive self-image. This implies that a smartphone is a symbolic product that can signal affiliation and enhance the users' status in a group. The results also indicate that hedonic enjoyment is equally important as utilitarian usefulness in predicting the adoption intention, and the two variables mediate the relationships between SI, positive self-image, perceived technicality, and the intention to use. Consequently, the results reveal that smartphones are convergent media that can be viewed as both task-oriented and entertainment-oriented devices.