Neural correlates of infant action processing relate to theory of mind in early childhood

The mechanisms that support infant action processing are thought to be involved in the development of later social cognition. While a growing body of research demonstrates longitudinal links between action processing and explicit theory of mind (TOM), it remains unclear why this link emerges in some measures of action encoding and not others. In this paper, we recruit neural measures as a unique lens into which aspects of human infant action processing (i.e., action encoding and action execution; age 7 months) are related to preschool TOM (age 3 years; n = 31). We test whether individual differences in recruiting the sensorimotor system or attention processes during action encoding predict individual differences in TOM. Results indicate that reduced occipital alpha during action encoding predicts TOM at age 3. This finding converges with behavioral work and suggests that attentional processes involved in action encoding may support TOM. We also test whether neural processing during action execution draws on the proto‐substrates of effortful control (EC). Results indicate that frontal alpha oscillatory activity during action execution predicted EC at age 3—providing strong novel evidence that infant brain activity is longitudinally linked to EC. Further, we demonstrate that EC mediates the link between the frontal alpha response and TOM. This indirect effect is specific in terms of direction, neural response, and behavior. Together, these findings converge with behavioral research and demonstrate that domain general processes show strong links to early infant action processing and TOM.     

刺激前alpha振荡对视知觉的影响

人类对感觉阈限附近的视觉刺激的知觉不总是一致的。为探究这种视知觉不一致的现象及其神经机制, 一些研究者关注刺激前脑内自发alpha神经振荡(8~13 Hz)对视知觉的影响。近年来的研究发现, 刺激前alpha振荡能量的降低能提高被试的探测击中率, 但不能提高知觉精确度; 而刺激前alpha振荡的相位能预测被试能否成功探测刺激。刺激前alpha能量被认为调控了视皮层的基础活动强度; alpha能量的降低反映了皮层基础活动的增强, 进而提高了对较弱刺激的探测率。刺激前alpha相位则被认为调控了皮层兴奋和抑制的时间; 大脑在刺激呈现时的不同状态(兴奋/抑制)决定了最终的知觉结果。     

融合视角下创造力的认知神经机制

创造力的认知神经机制是近年来心理学研究领域的前沿和热点问题。通过融合创造力整体宏观视角和创造性产生过程的微观视角,对创造力的认知神经机制进行了综述。宏观视角下,创造力主要涉及α波和大脑前额叶、内外侧颞叶以及外侧顶叶; 微观视角下,在创造力产生过程中主要涉及α波序列位置效应以及默认网络和执行控制网络的功能耦合。未来研究方向应该结合多模态脑成像数据库,利用机器算法来探究创造力的本质; 关注青少年群体创造力的纵向发展趋势; 结合分子遗传学研究,探究与创造力有关的基因问题。     

长时联结表征对工作记忆的抑制效应

本研究通过两个实验探讨了长时记忆联结表征如何影响当下工作记忆任务的加工。长时记忆联结表征采用无语义联系、无视觉相似性的Emoji图片对, 提前一天让被试完成联结表征的建立, 正式工作记忆任务采用独立探测的变化觉察范式。实验1控制呈现时间(500 ms / 1000 ms)与呈现方式(联结/独立), 发现两种呈现时间均显示出联结条件的正确率与记忆容量显著低于独立条件, 说明长时记忆联结表征抑制了当前工作记忆的加工。实验2设置了记忆项目数(2/4/6项)与呈现方式(联结/独立), 采用alpha震荡作为脑电指标, 考察长时联结表征在工作记忆维持阶段的作用。结果发现在维持阶段, 独立条件的alpha震荡随着记忆项目数量的增加而增大(2项 < 4项 < 6项), 而联结条件在4项已经到达顶点(2项 < 4项 = 6项)。实验2进一步说明长时联结表征在维持阶段降低了当前工作记忆容量。本研究的两个实验结果表明, 长时记忆联结表征对当前的工作记忆任务有一定的抑制作用, 这种抑制作用产生的机制可能来自于联结表征干扰了维持阶段的注意分配。     

On the distribution of the maximum likelihood estimator of Cronbach's alpha

The asymptotic normal distribution of the maximum likelihood estimator of Cronbach's alpha (under normality) is derived for the case when no assumptions are made about the covariances among items. The asymptotic distribution is also considered for the special case of compound symmetry and compared to the exact distribution.The authors would like to thank Willem J. Heiser, an associate editor and the reviewers for valuable and helpful comments to improve the quality of this work.     

Tests for equality of several alpha coefficients when their sample estimates are dependent

In a variety of measurement situations, the researcher may wish to compare the reliabilities of several instruments administered to the same sample of subjects. This paper presents eleven statistical procedures which test the equality ofm coefficient alphas when the sample alpha coefficients are dependent. Several of the procedures are derived in detail, and numerical examples are given for two. Since all of the procedures depend on approximate asymptotic results, Monte Carlo methods are used to assess the accuracy of the procedures for sample sizes of 50, 100, and 200. Both control of Type I error and power are evaluated by computer simulation. Two of the procedures are unable to control Type I errors satisfactorily. The remaining nine procedures perform properly, but three are somewhat superior in power and Type I error control.A more detailed version of this paper is also available.     

A loss function for alpha factor analysis

Most of the factor solutions can be got by minimizing a corresponding loss function. However, up to now, a loss function for the alpha factor analysis (AFA) has not been known. The present paper establishes such a loss function for the AFA. Some analogies to the maximum likelihood factor analysis are discussed.The author is greatly indebted to Prof. Henry F. Kaiser (University of California, Berkeley) for his kind encouragement. He is also indebted to an anonymous referee ofPsychometrika for having confronted him with the problem in 1977. Financial support by the Wiener Hochschuljubiläumsstiftung is gratefully acknowledged.     

Lower bounds for the reliability of the total score on a test composed of non-homogeneous items: I: Algebraic lower bounds

Let Σ _x be the (population) dispersion matrix, assumed well-estimated, of a set of non-homogeneous item scores. Finding the greatest lower bound for the reliability of the total of these scores is shown to be equivalent to minimizing the trace of Σ _x by reducing the diagonal elements while keeping the matrix non-negative definite. Using this approach, Guttman's bounds are reviewed, a method is established to determine whether his λ₄ (maximum split-half coefficient alpha) is the greatest lower bound in any instance, and three new bounds are discussed. A geometric representation, which sheds light on many of the bounds, is described. Present affiliation of the second author: Department of Statistics, University of Nigeria (Nsukka Campus). Work on this paper was carried out while on study leave in Aberystwyth.     

Note on two generalizations of coefficient alpha

An important relationship is given for two generalizations of coefficient alpha, Rajaratnam, Cronbach and Gleser's generalizability formula for stratified-parallel tests and Raju's coefficient beta.The author gratefully acknowledges the generous assistance given by reviewers and the editor.