Experimental Power for Indirect Effects in Group-randomized Studies with Group-level Mediators

Mediation analyses have provided a critical platform to assess the validity of theories of action across a wide range of disciplines. Despite widespread interest and development in these analyses, literature guiding the design of mediation studies has been largely unavailable. Like studies focused on the detection of a total or main effect, an important design consideration is the statistical power to detect indirect effects if they exist. Understanding the sensitivity to detect indirect effects is exceptionally important because it directly influences the scale of data collection and ultimately governs the types of evidence group-randomized studies can bring to bear on theories of action. However, unlike studies concerned with the detection of total effects, literature has not established power formulas for detecting multilevel indirect effects in group-randomized designs. In this study, we develop closed-form expressions to estimate the variance of and the power to detect indirect effects in group-randomized studies with a group-level mediator using two-level linear models (i.e., 2-2-1 mediation). The results suggest that when carefully planned, group-randomized designs may frequently be well positioned to detect mediation effects with typical sample sizes. The resulting power formulas are implemented in the R package PowerUpR and the PowerUp!-Mediator software (causalevaluation.org).     

Taking Stock of the Diversity and Sense of Community Debate

Over the past couple of years, a debate has played out in the pages of the American Journal of Community Psychology concerning the relationship between two of Community Psychology's core values: promoting diversity and promoting a sense of community. This special section is to continue a discussion about diversity and community, both among the debate's initial contributors (Alex Stivala, Greg Townley, and Zachary Neal), as well as among others whose own work has touched on these issues (Anne Brodsky, Richard Florida, Jean Hill, and Roderick Watts). In this essay, I address some broad questions that have emerged through this discussion. First, because much has been written on the relationship between diversity and community, both in community psychology and in other disciplines, what do we know, or at least think we know? Second, since the constructs of diversity and sense of community are complex and multi‐faceted, how can definitions get in the way and how can we avoid talking past one another in this discussion? Finally, looking across the original papers that initiated this discussion, as well as the contributions in this special section, what path(s) forward do we have?     

Emotion perception from a componential perspective

The common conceptual understanding of emotion is that they are multi-componential, including subjective feelings, appraisals, psychophysiological activation, action tendencies, and motor expressions. Emotion perception, however, has traditionally been studied in terms of emotion labels, such as “happy”, which do not clearly indicate whether one, some, or all emotion components are perceived. We examine whether emotion percepts are multi-componential and extend previous research by using more ecologically valid, dynamic, and multimodal stimuli and an alternative response measure. The results demonstrate that observers can reliably infer multiple types of information (subjective feelings, appraisals, action tendencies, and social messages) from complex emotion expressions. Furthermore, this finding appears to be robust to changes in response items. The results are discussed in light of their implications for research on emotion perception.     

Does a Religious Transformation Buffer the Effects of Lifetime Trauma on Happiness?

A number of studies have examined religious transformations. But most of this work has been concerned with identifying different types of transformations and steps in the process of transformation. The current study was designed to examine the ways in which religious transformations may be associated with happiness. We take a novel approach toward the evaluation of this relationship. We argue that a religious transformation may be an important resource for coping with lifetime trauma. Two major findings emerge from our nationwide survey (N = 2,851). First, the data indicate that the magnitude of the relationship between lifetime trauma and happiness is reduced significantly for people who have had a religious transformation but not for those who have not had this type of religious experience. Second, the results reveal that the potential stress-related benefits of a religious transformation are more evident among younger adults than among middle-aged or older adults.     

Subtyping obsessive-compulsive disorder: A taxometric analysis

Obsessive-compulsive disorder (OCD) is a heterogeneous condition comprising multiple symptoms. Researchers have identified OCD subtypes using a range of symptom-based research methods, including factor and cluster analyses and examination of differential treatment response. These methods can be challenged on the grounds that they fail to demonstrate the existence of discrete taxonomic entities. Furthermore, no study has examined subtyping on the basis of cognitive characteristics. In the present study, the categorical vs. dimensional status of 6 possible subtypes of OCD was examined using taxometric methods. Three potential cognitive subtypes (based on high levels of responsibility/threat estimation, perfectionism/certainty, and importance/control of thoughts) and 3 potential symptomatic subtypes (based on elevated levels of contamination obsessions and cleaning compulsions, checking, and obsessionality) were examined using the MAXEIG and MAMBAC procedures in a sample of 404 diagnosed cases of OCD. Findings favored dimensional models of the potential responsibility, perfectionism, checking, and contamination subtypes, but offered qualified support for taxonic models of the importance/control of thoughts and obsessional subtypes. Implications for the subclassification of OCD are discussed.     

隔代“亲”的社会心理解析

隔代抚育中出现了普遍的隔代“亲”现象。本文分别从文化传统（血缘宗亲）、心理需求、社会现实、补偿心理等几个方面来阐述隔代“亲”的成因。     

How checking as a cognitive style influences working memory performance

Compulsive checking is known to influence memory, yet there is little consideration of checking as a cognitive style within the typical population. We employed a working memory task where letters had to be remembered in their locations. The key experimental manipulation was to induce repeated checking after encoding by asking about a stimulus that had not been presented. We recorded the effect that such misleading probes had on a subsequent memory test. Participants drawn from the typical population but who scored highly on a checking‐scale had poorer memory and less confidence than low scoring individuals. While thoroughness is regarded as a quality, our results indicate that a cognitive style that favours repeated checking does not always lead to the best performance as it can undermine the authenticity of memory traces. This may affect various aspects of everyday life including the work environment and we discuss its implications and possible counter‐measures. Copyright © 2010 John Wiley & Sons, Ltd.     

Where to look first for an explanation of induction with uncertain categories

Recent research has examined how people predict unobserved features of an object when its category membership is ambiguous. The debate has focused on whether predictions are based solely on information from the most likely category, or whether information from other possible categories is also used. In the present experiment, we compared these category-based approaches with feature conjunction reasoning, where predictions are based on a comparison among exemplars (rather than categories) that share features with a target object. Reasoning strategies were assessed by examining patterns of feature prediction and by using an eye gaze measure of attention during induction. The main findings were (1) the majority of participants used feature conjunction rather than categorical strategies, (2) people predominantly gazed at the exemplars that were most similar to the target object, and (3) although people gazed most at the most probable category to which an object could belong, they also attended to other plausible category alternatives during induction. These findings question the extent to which category-based reasoning is used for induction when category membership is uncertain.