Multiple trials may yield exaggerated effect size estimates

Published psychological research attempting to support the existence of small and medium effect sizes may not have enough participants to do so accurately, and thus, repeated trials or the use of multiple items may be used in an attempt to obtain significance. Through a series of Monte-Carlo simulations, this article describes the results of multiple trials or items on effect size estimates when the averages and aggregates of a dependent measure are analyzed. The simulations revealed a large increase in observed effect size estimates when the numbers of trials or items in an experiment were increased. Overestimation effects are mitigated by correlations between trials or items, but remain substantial in some cases. Some concepts, such as a P300 wave or a test score, are best defined as a composite of measures. Troubles may arise in more exploratory research where the interrelations among trials or items may not be well described.     

A generalized least squares regression approach for computing effect sizes in single-case research: application examples

A new method for deriving effect sizes from single-case designs is proposed. The strategy is applicable to small-sample time-series data with autoregressive errors. The method uses Generalized Least Squares (GLS) to model the autocorrelation of the data and estimate regression parameters to produce an effect size that represents the magnitude of treatment effect from baseline to treatment phases in standard deviation units. In this paper, the method is applied to two published examples using common single case designs (i.e., withdrawal and multiple-baseline). The results from these studies are described, and the method is compared to ten desirable criteria for single-case effect sizes. Based on the results of this application, we conclude with observations about the use of GLS as a support to visual analysis, provide recommendations for future research, and describe implications for practice.     

Understanding children's emotional processes and behavioral strategies in the context of marital conflict

Marital conflict is a distressing context in which children must regulate their emotion and behavior; however, the associations between the multidimensionality of conflict and children’s regulatory processes need to be examined. The current study examined differences in children’s (N = 207, mean age = 8.02 years) emotions (mad, sad, scared, and happy) and behavioral strategies to regulate conflict exposure during resolved, unresolved, escalating, and child-rearing marital conflict vignettes. Children’s cortisol levels were assessed in relation to child-rearing and resolved conflict vignettes. Anger and sadness were associated with escalating and child-rearing conflicts, fearfulness was related to escalating and unresolved conflicts, and happiness was associated with resolution. Anger was associated with children’s strategies to stop conflict, whereas sadness was associated with monitoring and avoidant strategies. Cortisol recovery moderated the link between fearfulness and behavioral regulation. These results highlight the importance of children’s emotions and regulatory processes in understanding the impact of marital conflict.     

Working memory components as predictors of children's mathematical word problem solving

This study determined the working memory (WM) components (executive, phonological loop, and visual–spatial sketchpad) that best predicted mathematical word problem-solving accuracy of elementary school children in Grades 2, 3, and 4 (N = 310). A battery of tests was administered to assess problem-solving accuracy, problem-solving processes, WM, reading, and math calculation. Structural equation modeling analyses indicated that (a) all three WM components significantly predicted problem-solving accuracy, (b) reading skills and calculation proficiency mediated the predictive effects of the central executive system and the phonological loop on solution accuracy, and (c) academic mediators failed to moderate the relationship between the visual–spatial sketchpad and solution accuracy. The results support the notion that all components of WM play a major role in predicting problem-solving accuracy, but basic skills acquired in specific academic domains (reading and math) can compensate for some of the influence of WM on children’s mathematical word problem solving.     

Economic Hardship, Neighborhood Context, and Parenting: Prospective Effects on Mexican�CAmerican Adolescent��s Mental Health

This study examined family and neighborhood influences relevant to low-income status to determine how they combine to predict the parenting behaviors of Mexican-American mothers and fathers. The study also examined the role of parenting as a mediator of these contextual influences on adolescent internalizing and externalizing symptoms. Study hypotheses were examined in a diverse sample of Mexican-American families in which 750 mothers and 467 fathers reported on their own levels of parental warmth and harsh parenting. Family economic hardship, neighborhood familism values, and neighborhood risk indicators were all uniquely associated with maternal and paternal warmth, and maternal warmth mediated the effects of these contextual influences on adolescent externalizing symptoms in prospective analyses. Parents' subjective perceptions of neighborhood danger interacted with objective indicators of neighborhood disadvantage to influence maternal and paternal warmth. Neighborhood familism values had unique direct effects on adolescent externalizing symptoms in prospective analyses, after accounting for all other context and parenting effects.     

Drugs' rapid payoffs distort evaluation of their instrumental uses

Science has needed a dispassionate valuation of psychoactive drugs, but a motivational analysis should be conducted with respect to long-term reward rather than reproductive fitness. Because of hyperbolic overvaluation of short-term rewards, an individual's valuation depends on the time she forms it and the times she will revisit it, sometimes making her best long-term interest lie in total abstinence.     

Understanding the relationships between age,gender, and life satisfaction: the mediating role of stress and religiosity

Although hundreds of investigations have examined the relationship between age and life satisfaction, a recent review of these studies reveals that relatively little is known about the nature of this relationship, especially between genders and across cultures, and the mechanisms that link age to life satisfaction. Using a large-scale study in Malaysia, the present research explores the mediating effects of stress and religiosity that might be responsible for the empirical findings reported in previous studies. Contrary to previous findings based on US studies, this study finds that women are more satisfied with their lives than men in the early and later stages of life. Chronic stress and religiosity were found to partially mediate the relationship between age and life satisfaction, suggesting that these may be mechanisms that explain the findings of previous studies.