Bond modulus and stability of covalent solids

The chemical stabilities of molecules are determined by their LUMO–HOMO energy gaps. For solids, the analogues of these are their energy band gaps. However, solids are aggregates of molecules, so an energy alone cannot characterize their stabilities. An intensive parameter is needed. Such a parameter is the gap energy per molecular volume. The author has coined the name ‘bond modulus’ for this parameter because it tends to be proportional to elastic moduli and it has the same dimensions. It applies primarily to covalent solids with localized bonding. It is proportional to chemical hardnesses and bulk moduli, as well as octahedral shear moduli and inverse polarizabilities.     

Attention,spatial integration,and the tail of response time distributions in Stroop task performance

A few studies have examined selective attention in Stroop task performance through ex-Gaussian analyses of response time (RT) distributions. It has remained unclear whether the tail of the RT distribution in vocal responding reflects spatial integration of relevant and irrelevant attributes, as suggested by Spieler, Balota, and Faust (2000 Spieler, D. H., Balota, D. A. and Faust, M. E. 2000. Levels of selective attention revealed through analyses of reaction time distributions. Journal of Experimental Psychology: Human Perception and Performance, 26: 506–526. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). Here, two colour–word Stroop experiments with vocal responding are reported in which the spatial relation between colour and word was manipulated. Participants named colours (e.g., green; say “green”) while trying to ignore distractors that were incongruent or congruent words (e.g., red or green), or neutral series of Xs. The vocal RT was measured. Colour words in colour, white words superimposed onto colour rectangles (Experiment 1), and colour rectangles combined with auditory words (Experiment 2) yielded Stroop effects in both the leading edge and the tail of the RT distributions. These results indicate that spatial integration is not necessary for effects in the tail to occur in vocal responding. It is argued that the findings are compatible with an association of the tail effects with task conflict.     

From mental strain to burnout

This study examines the relationships between burnout and short-term consequences of mental strain within and outside human services professions, at the same time contributing to the understanding of the development of burnout as a long-term effect of impairing work and job design. A total of 294 German employees working in human services (N = 149) and industrial production (N = 145) completed the Oldenburg Burnout Inventory (OLBI) and four scales measuring short-term consequences of mental strain. Results of factor analyses confirmed that the elements of the OLBI's two-factor structure—exhaustion and disengagement—are distinct from a range of impairing short-term consequences of mental strain. In addition, structural equation modelling showed that each burnout dimension is differentially related to specific short-term consequences of strain: Exhaustion is primarily related to mental fatigue, whereas disengagement is primarily related to satiation and the experience of monotony. The findings did not differ substantially for the two occupational groups. Burnout, as a long-term consequence of impairing mental strain, is distinct from and presumably temporally-causally related to specific impairing short-term consequences of mental strain, which, in turn, can be attributed to inadequate job design.     

A latent class distance association model for cross‐classified data with a categorical response variable

In this paper we propose a latent class distance association model for clustering in the predictor space of large contingency tables with a categorical response variable. The rows of such a table are characterized as profiles of a set of explanatory variables, while the columns represent a single outcome variable. In many cases such tables are sparse, with many zero entries, which makes traditional models problematic. By clustering the row profiles into a few specific classes and representing these together with the categories of the response variable in a low‐dimensional Euclidean space using a distance association model, a parsimonious prediction model can be obtained. A generalized EM algorithm is proposed to estimate the model parameters and the adjusted Bayesian information criterion statistic is employed to test the number of mixture components and the dimensionality of the representation. An empirical example highlighting the advantages of the new approach and comparing it with traditional approaches is presented.     

Bayes Factors Have Frequency Properties—This Should Not Be Ignored: A Rejoinder to Morey,Wagenmakers, and Rouder

Hoijtink, van Kooten, and Hulsker (2016 Hoijtink, H., van Kooten, P., &; Hulsker, K. (2016). Why Bayesian psychologists should change the way they used the Bayes factor. Multivariate Behavioral Research, 51, 1--9. doi: 10.1080/00273171.2014.969364.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) outline a research agenda for Bayesian psychologists: evaluate and use the frequency properties of Bayes factors. Morey, Wagenmakers, and Rouder (2016 Morey, R. D., Wagenmakers, E. -J., &; Rouder, J. N. (2016). Calibrated Bayes factors should not be used: A reply to Hoijtink, van Kooten, and Hulsker. Multivariate Behavioral Research, 51, 10--17. doi: 10.1080/00273171.2015.1052710.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]) respond that Bayes factors calibrated using frequency properties should not be used. This paper contains the response of Hoijtink, van Kooten, and Hulsker to the criticism of Morey, Wagenmakers, and Rouder (2016 Morey, R. D., Wagenmakers, E. -J., &; Rouder, J. N. (2016). Calibrated Bayes factors should not be used: A reply to Hoijtink, van Kooten, and Hulsker. Multivariate Behavioral Research, 51, 10--17. doi: 10.1080/00273171.2015.1052710.[Taylor &; Francis Online], [Web of Science ®] , [Google Scholar]).     

True overconfidence: The inability of rational information processing to account for apparent overconfidence

The better-than-average effect describes the tendency of people to perceive their skills and virtues as being above average. We derive a new experimental paradigm to distinguish between two possible explanations for the effect, namely rational information processing and overconfidence. Experiment participants evaluate their relative position within the population by stating their complete belief distribution. This approach sidesteps recent methodology concerns associated with previous research. We find that people hold beliefs about their abilities in different domains and tasks which are inconsistent with rational information processing. Both on an aggregated and an individual level, they show considerable overplacement. We conclude that overconfidence is not only apparent overconfidence but rather the consequence of a psychological bias.     

Implementing continuous non-normal skewed distributions in latent growth mixture modeling: An assessment of specification errors and class enumeration

Abstract

Recent advances have allowed for modeling mixture components within latent growth modeling using robust, skewed mixture distributions rather than normal distributions. This feature adds flexibility in handling non-normality in longitudinal data, through manifest or latent variables, by directly modeling skewed or heavy-tailed latent classes rather than assuming a mixture of normal distributions. The aim of this study was to assess through simulation the potential under- or over-extraction of latent classes in a growth mixture model when underlying data follow either normal, skewed-normal, or skewed-t distributions. In order to assess this, we implement skewed-t, skewed-normal, and conventional normal (i.e., not skewed) forms of the growth mixture model. The skewed-t and skewed-normal versions of this model have only recently been implemented, and relatively little is known about their performance. Model comparison, fit, and classification of correctly specified and mis-specified models were assessed through various indices. Findings suggest that the accuracy of model comparison and fit measures are dependent on the type of (mis)specification, as well as the amount of class separation between the latent classes. A secondary simulation exposed computation and accuracy difficulties under some skewed modeling contexts. Implications of findings, recommendations for applied researchers, and future directions are discussed; a motivating example is presented using education data.     

A Latent Block Distance-Association Model for Profile by Profile Cross-Classified Categorical Data

Abstract

Distance association models constitute a useful tool for the analysis and graphical representation of cross-classified data in which distances between points inversely describe the association between two categorical variables. When the number of cells is large and the data counts result in sparse tables, the combination of clustering and representation reduces the number of parameters to be estimated and facilitates interpretation. In this article, a latent block distance-association model is proposed to apply block clustering to the outcomes of two categorical variables while the cluster centers are represented in a low dimensional space in terms of a distance-association model. This model is particularly useful for contingency tables in which both the rows and the columns are characterized as profiles of sets of response variables. The parameters are estimated under a Poisson sampling scheme using a generalized EM algorithm. The performance of the model is tested in a Monte Carlo experiment, and an empirical data set is analyzed to illustrate the model.     

Do 5- and 6-Year-Old Children Attempt to Appear Fair to Others?

Abstract

Children come to prefer fair distributions at the age of 5 to 6?years. But do they actually want to be fair, or do they want to appear fair to others? In three conditions, an experimenter initially distributed chocolates to 5-/6-year-old participants and partners they were paired with. Participants always possessed, through some means, two chocolates when the experimenter returned after a brief absence, and they had to decide whether to take an extra one for themselves. To measure the extent to which children were concerned with actually being fair versus appearing fair, two conditions were created in which children were led to believe that the experimenter did not know that the distributions had become equal. In the windfall condition, a confederate gave one additional chocolate to the participant, and in the partner condition, the partner transferred one chocolate to the participant. Compared to the control condition, participants who passed the false belief task in both of these conditions tried to appear fair in their distribution. Thus 5-/6-year-old children seem to prefer appearing fair to others regardless of the situation.