Alternating least squares algorithms for simultaneous components analysis with equal component weight matrices in two or more populations

Millsap and Meredith (1988) have developed a generalization of principal components analysis for the simultaneous analysis of a number of variables observed in several populations or on several occasions. The algorithm they provide has some disadvantages. The present paper offers two alternating least squares algorithms for their method, suitable for small and large data sets, respectively. Lower and upper bounds are given for the loss function to be minimized in the Millsap and Meredith method. These can serve to indicate whether or not a global optimum for the simultaneous components analysis problem has been attained.Financial support by the Netherlands organization for scientific research (NWO) is gratefully acknowledged.     

Psychophysiological arousal related to Type A components in adolescent boys

The association between psychophysiological responses (heart rate, skin conductance and blood volume) and Type A behavior was studied in adolescent boys (n = 48) in computer-controlled experiments. Although psychophysiological arousal was related to the type of stress-evoking element, task-specificity did not result in significant psychophysiological differences between Type As and Nontype As. The indication is that physiological arousal may be a constitutional characteristic of Type A behavior. The multidimensionality of type A behavior must be considered in any investigation examining the psychophysiological Type A-Nontype A differences. Different Type A dimensions, together with previously found psychological differences, were related to specific psychophysiological reactions.     

On the optimality of the simultaneous redundancy transformations

The objective of this paper is to introduce and motivate additional properties and interpretations for the redundancy variables. It is shown that these variables can be derived by application of certain invariance arguments and without reference to the index of redundancy. In addition, an optimality property for the variables is presented which is important whenever one restricts attention in a study to a subset of the redundancy variables. This optimality property pertains to the subset rather than to the individual variables.This paper is based in part on the author's doctoral dissertation, Department of Statistics, Princeton, University. Research was conducted under the supervision of Lawrence S. Mayer.     

On rotating to smooth functions

Tucker has outlined an application of principal components analysis to a set of learning curves, for the purpose of identifying meaningful dimensions of individual differences in learning tasks. Since the principal components are defined in terms of a statistical criterion (maximum variance accounted for) rather than a substantive one, it is typically desirable to rotate the components to a more interpretable orientation. Simple structure is not a particularly appealing consideration for such a rotation; it is more reasonable to believe that any meaningful factor should form a (locally) smooth curve when the component loadings are plotted against trial number. Accordingly, this paper develops a procedure for transforming an arbitrary set of component reference curves to a new set which are mutually orthogonal and, subject to orthogonality, are as smooth as possible in a well defined (least squares) sense. Potential applications to learning data, electrophysiological responses, and growth data are indicated.Portions of this research were supported by the National Research Council of Canada, Grant A8615 to the second author. We thank Jagdeth Sheth for supplying his raw data.     

The competition-among-relations-in-nominals theory of conceptual combination: implications for stimulus class formation and class expansion

One way in which new concepts are added to the conceptual system is through conceptual combination. The competition-among-relations-in-nominals (CARIN) theory (Gagné & Shoben, 1997) proposes that conceptual combination involves specifying a thematic relation (e.g., noun MADE OF modifier) to link the constituent concepts (e.g., chocolate and bee). This theory claims that relations have different strengths for various concepts that correspond to how often a modifier and relation have been paired in previous encounters with combined concepts and that this relational knowledge strongly affects the ease with which combined concepts can be formed. A mathematical model that incorporates key claims of the theory is presented, and empirical findings that are relevant to evaluating the CARIN theory are reviewed. The parallels between the CARIN theory and approaches to stimulus class formation are also discussed.     

科学主义的尴尬与中医学的多向度发展

近５０年的中医现代化研究暴露了科学主义试图消解其他向度存在的独尊倾向,而经络实质研究、证客观化研究等方面的失败,宣告了科学主义并不是解决中医学所有问题的灵丹妙药。科学主义所遇到的这种尴尬局面表明,中医学应该有多种向度的发展,除了现代化研究这一模式之外,至少还应当有两种向度的存在,即原有形态的传统中医学体系应继续存在下去,传统中医学在技术上与西医学的结合应当受到鼓励。     

Stressors Experienced During Deployment Among Canadian Armed Forces Personnel: Factor Structure of Two Combat Exposure Scales

Combat exposure is linked to increased mental health problems among military personnel. Reliable, precise, and efficient measurement of combat experiences can facilitate understanding of the effects of combat on mental health. This study examined the psychometric properties of 2 scales used to assess deployment experiences in Canadian Armed Forces (CAF) personnel in 2 different settings: during a Third Location Decompression (TLD) program after deployment, and during routine postdeployment screening. Principal components analyses yielded similar results for the 2 measures. The components containing items relevant to Exposure to the Dead and Injured, Dangerous Environment, and Active Combat were common across both surveys. The TLD results revealed a fourth component, Personal Suffering, while the postdeployment screening data revealed a fourth component, Perceived Responsibility. This study found categories of deployment stressors that can be used for further analysis, and underscores the importance of assessing a broad range of exposures in the combat environment.     

Improved Insight into and Prediction of Network Dynamics by Combining VAR and Dimension Reduction

To understand within-person psychological processes, one may fit VAR(1) models (or continuous-time variants thereof) to multivariate time series and display the VAR(1) coefficients as a network. This approach has two major problems. First, the contemporaneous correlations between the variables will frequently be substantial, yielding multicollinearity issues. In addition, the shared effects of the variables are not included in the network. Consequently, VAR(1) networks can be hard to interpret. Second, crossvalidation results show that the highly parametrized VAR(1) model is prone to overfitting. In this article, we compare the pros and cons of two potential solutions to both problems. The first is to impose a lasso penalty on the VAR(1) coefficients, setting some of them to zero. The second, which has not yet been pursued in psychological network analysis, uses principal component VAR(1) (termed PC-VAR(1)). In this approach, the variables are first reduced to a few principal components, which are rotated toward simple structure; then VAR(1) analysis (or a continuous-time analog) is applied to the rotated components. Reanalyzing the data of a single participant of the COGITO study, we show that PC-VAR(1) has the better predictive performance and that networks based on PC-VAR(1) clearly represent both the lagged and the contemporaneous variable relations.     

Materials used to support cognitive behavioural therapy for depression: a survey of therapists’ clinical practice and views

ABSTRACT

Use of supporting materials in cognitive behavioural therapy (CBT) is widely advocated, and homework increases effectiveness. The study aimed to identify materials most frequently used by CBT therapists to support CBT for depression, and those perceived clinically most effective. Questionnaires were sent to 3665 accredited CBT therapists asking about their use of resources commonly described in CBT manuals, and their views on effectiveness. Of 3665 approached by post/email, 994 (27%) responded. Another 33 completed the questionnaire via the study website. 818/1027 (80%) of respondents were accredited practitioners who deliver one-to-one therapy. Symptom measures, lists of problems/goals, activity schedules, behavioural activation diaries/plans, and case formulation worksheets were used “frequently” or “very frequently” by over 85% of respondents. Sleep diaries and computerised CBT were used least. Most resources were used within and between sessions. Activity schedules, behavioural activation diaries/plans, case formulation worksheets, thought records, and resources to support the identification of conditional beliefs were regarded as most effective. Symptom measures, sleep diaries, and computerised/online materials were considered only moderately effective. Therapists use a wide range of materials to support individual CBT. For delivering CBT, technology-enabled approaches should incorporate a range of materials to enable therapists to tailor treatment effectively.