Effect size measures for mediation models: quantitative strategies for communicating indirect effects

The statistical analysis of mediation effects has become an indispensable tool for helping scientists investigate processes thought to be causal. Yet, in spite of many recent advances in the estimation and testing of mediation effects, little attention has been given to methods for communicating effect size and the practical importance of those effect sizes. Our goals in this article are to (a) outline some general desiderata for effect size measures, (b) describe current methods of expressing effect size and practical importance for mediation, (c) use the desiderata to evaluate these methods, and (d) develop new methods to communicate effect size in the context of mediation analysis. The first new effect size index we describe is a residual-based index that quantifies the amount of variance explained in both the mediator and the outcome. The second new effect size index quantifies the indirect effect as the proportion of the maximum possible indirect effect that could have been obtained, given the scales of the variables involved. We supplement our discussion by offering easy-to-use R tools for the numerical and visual communication of effect size for mediation effects.     

Earwitness Testimony: Never Mind the Variety,Hear the Length

Three aspects of voice recognition were investigated in the study reported here: memory for familiar voices, memory for the words spoken, and the relative effects of length and variation in a voice extract on long- and short-term memory. In Experiment 1, recognition memory for the briefly heard voice of a stranger was superior with longer extracts (p<0.01), but increasing vowel variety did not improve performance. This pattern was repeated for short-term memory (p<0.01) in Experiment 2. Scores for the above task correlated significantly (p<0.05) with scores for recognizing well-known voices. In a further test of well-known voice memory in Experiment 3, a weak and non-significant positive correlation (r=0.29) was found between memory for well-known voices and memory for a once-heard voice. Memory for the words spoken did not correlate significantly with memory for the unknown voice itself. The possibilities of a memory-for-voices general ability, and forensic applications of the findings are discussed. © 1997 by John Wiley & Sons, Ltd.     

Group versus individual decision making: An investigation of performance measures,decision strategies,and process losses/gains

The relative effectiveness of individual and group performance was investigated by employing three decision making strategies. Ignoring this consideration, group decisions were superior (p ⩽ .01) to individual averages, equal to the selected best individual decisions, and inferior to the actual best individual solutions (p ⩽ .05). The results indicated that the degree of process loss/gain and the relative performance of groups and individuals was significantly influenced by the dependent variable utilized and the decision making strategy employed.     

When stereotype‐based expectancies impair performance: the effect of prejudice,race, and target quality on judgments and perceiver performance

High‐ and low‐prejudiced participants were presented with a lecture segment in which the race of the professor (White or Black) and lecture quality (high or low) were manipulated. Consistent with predictions, low‐prejudiced participants were more extreme in their evaluations (more negative) and performed more poorly on test items when presented with an expectancy‐violating low‐quality Black lecturer. High‐prejudiced participants were more extreme in their evaluations (more positive) and performed more poorly when presented with an expectancy‐violating high‐quality Black lecturer. Copyright © 1999 John Wiley & Sons, Ltd.     

First and second language in the brain: Neuronal correlates of language processing and spelling strategies

This study explores oscillatory brain activity by means of event-related synchronization and desynchronization (%ERS/ERD) of EEG activity during the use of phonological and orthographic-morphological spelling strategies in L2 (English) and L1 (German) in native German speaking children. EEG was recorded while 33 children worked on a task requiring either phonological or orthographic-morphological spelling strategies. L2 processing elicited more theta %ERS than L1 processing (particularly at bilateral frontal and right posterior parietal sites) which might suggest a stronger involvement of semantic encoding and retrieval of the less familiar L2. The highest level of theta %ERS was revealed for the orthographic-morphological strategy in L2 which might indicate a more intense way of lexical retrieval compared to the phonological strategy in L2 and the orthographic-morphological strategy in L1. Analyses moreover revealed that phonological processing (both in L1 and L2) was associated with comparatively strong left-hemispheric %ERD in the upper alpha frequency band.     

Overt and covert identification of fragmented objects inferred from performance and electrophysiological measures

The authors investigated visual processing leading to object identification by manipulating the number of fragments and nature of the study. During the study, participants either named or drew objects in Experiment 1 and drew them all in Experiment 2. During the test, participants made an identification judgment at each of 6 different fragmentation levels for studied and new objects. Fewer fragments were needed to identify studied than unstudied objects. Reaction times were faster for studied than unstudied objects both at identification and at the preceding level. Event-related brain potentials (ERPs) to unidentified objects were characterized by a late negativity in contrast to a positivity to identified objects. ERPs to studied but not to new objects contained a smaller and later version of the identification positivity at level just prior to identification, which was not due to differential response confidence. Much covert visual analysis and even object identification may precede overt identification, depending on the nature of prior experience.     

语言和文化影响颜色认知：直接语言效应抑或间接语言效应?

语言和文化对颜色认知的影响存在着直接语言效应和间接语言效应的争论。直接语言效应是指在识记颜色时人先将颜色转换成颜色名称, 再认时通过匹配保留在记忆中的颜色词与目标颜色名称来完成任务。颜色类别知觉是语言策略的结果。间接语言效应是指语言和文化塑造颜色知觉表征, 形成了一个曲形颜色知觉空间, 将人们的注意引向语言和文化定义的颜色类别分界。即使没有语言策略的参与, 类别效应也会出现。颜色文化是民族文化的重要组成部分。绿色和红色在维吾尔族和汉族的语言和文化中分别具有重要的意义。采用颜色相似性判断、颜色分类和颜色再认任务, 考察维吾尔族和汉族的大学生对红、绿的认知, 探查语言和文化对颜色认知的影响及其性质。结果表明, 与汉族相比, 维吾尔族对绿色的辨认、分类和再认存在反应优势, 对红色认知存在反应劣势。与颜色辨认反应比, 两个民族的颜色再认反应时显著长。整个研究表明, 语言和文化对颜色认知的影响存在着间接语言效应, 语言与文化塑造个体的颜色知觉空间。     

Presentation modality and indirect performance information: effects on ratings,reactions, and memory

The authors investigated whether raters integrate indirect (second-hand) information from an employee's co-worker with their direct observations when completing performance evaluations. Performance levels of direct and indirect information and presentation modality (auditory vs. textual) were manipulated (N = 220). Results showed that indirect information was perceived to be of highest utility when the performance levels of the direct and indirect information were consistent. Confidence in performance ratings was lowest when the indirect source delivered negative performance feedback that was contrary to the rater's own positive observations. Indirect information was only reflected in the performance ratings when direct observations were positive. There was a significant 3-way interaction between performance level of the direct information, performance level of the indirect information, and presentation modality on memory for performance incidents.     

On the universality of language comprehension strategies: evidence from Turkish

A fundamental question in psycholinguistic research concerns the universality of comprehension strategies. We investigated this issue by examining the so-called "subject preference" in Turkish, a language which allows for a natural (unmarked) object reading of an initial ambiguous argument. Using event-related brain potentials (ERPs), we observed increased processing difficulty in the form of a broadly distributed positivity when an initial ambiguous argument was disambiguated towards an object reading. This effect was independent of the animacy (i.e. semantic subject prototypicality) of the ambiguous argument. Our results therefore speak in favour of a universal tendency to interpret the first argument encountered as the "subject" of the clause, even in languages providing no obvious structural motivation for such a strategy. However, we argue that the underlying explanation for this preference must be modified in accordance with cross-linguistic considerations.     

Ecology,language, and performance on spatial cognitive tasks

The study of the orientation systems that people use in different cultures to describe the location of objects in space has drawn some interest of researchers in the fields of anthropology, psycholinguistics, and cognitive psychology. There has been a rethinking of the “linguistic relativity hypothesis,” and some empirical studies tend to support the notion that language is the major determinant of encoding and cognitive performance on spatial tasks. This paper reports a cross‐cultural study carried out with 545 children aged 4 to 14 years, both schooled and unschooled, in India and Nepal. The field sites were selected taking into consideration how reference to spatial locations is organized in the language as well as in the local cultural practices. In a village near Varanansi in India, people organize spatial locations mainly with reference to cardinal directions, but in the city of Varanasi, relative references are also used, although people in both the locations speak the same language (i.e., Hindi). In a village in Nepal, on the other hand, the “uphill‐downhill” geocentric frame of reference is the most compelling. We test the relationship between ecology, culture, and language, encoding of spatial information, and performance on some Piagetian spatial tasks, taking age and schooling into account. Berry's eco‐cultural model is used to discuss the findings that support linguistic relativism at the group but not at the individual level. Les systèmes d'orientation spatiale utilisés dans différentes sociétés pour décrire la localisation d'objets ont attiré L'attention de chercheurs en anthropologie, en psycholinguistique et en psychologie cognitive. L'hypothèse du relativisme linguistique a été remise à L'ordre du jour et des études empiriques ont montré que la langue était un déterminant majeur de L'encodage spatial et de la performance à des épreuves de cognition spatiale. Cet article porte sur une étude interculturelle comparative effectuée avec 545 enfants de 4 à 14 ans, scolarisés ou non, en Inde et au Népal. Les trois terrains ont été sélectionnés en tenant compte de la façon dont les références spatiales sont organisées aussi bien dans la langue que dans les pratiques culturelles locales. Dans un village près de Bénares, en Inde, les objets sont localisés selon les points cardinaux, alors que dans la ville de Bénares, des références relatives (droite, gauche, devant, derrière) sont également utilisées, alors que la langue parlée est la même (le Hindi). Dans un village au Népal, le système spatial le plus utilisé est un cadre de référence géocentrique formé par L'opposition «en haut vers la montagne/en bas vers la vallée». Nous étudions les relations entre L'écologie, la culture et la langue, L'encodage d'informations spatiales et la performance à des épreuves spatiales dérivées de la théorie de Piaget, en tenant compte de L'âge et de la scolarisation. Le modèle éco‐culturel de Berry est utilisé comme cadre théorique pour mettre en perspective les résultats, qui confirment le relativisme linguistique au niveau du groupe mais pas au niveau individuel. El estudio de los sistemas de orientación espacial utilizados en diversas culturas para describir la localización de los objetos ha atraído la atención de los investigadores en antropología, psicolingüística y psicología cognitiva. A partir de una renovación de la hipótesis del relativismo lingüístico, algunos estudios empíricos parecen apoyar la noción de que el lenguaje es el determinante más importante de la codificación y el desempeño cognitivo en tareas espaciales. El presente artículo informa sobre un estudio transcultural comparativo, efectuado con 545 niños de 4 a 14 años, escolarizados o no, urbanos y rurales, en India y en Nepal. Los sitios en donde se llevó a cabo el trabajo de campo se seleccionaron tomando en cuenta la forma en que se hace referencia a localizaciones espaciales en la lengua y en las prácticas culturales. En un pueblo de las planicies del Ganges, los habitantes organizan el espacio de manera geocéntrica, según los puntos cardinales, mientras que en la ciudad de Benares, también se utilizan referencias relativas (izquierda/derecha), aún cuando la lengua es la misma (el hindú). En un pueblo de Nepal, el cuadro de referencia geocéntrica “arriba/abajo” es predominante. El presente estudio examinó las relaciones entre la ecología, la cultura, la lengua, la codificación de la información espacial y el desempeño en algunas tareas espaciales de Piaget, teniendo en cuenta la edad y la escolarización. Este estudio está basado en el marco teórico eco‐cultural de Berry. Los resultados confirman una forma moderada de relativismo lingüístico a nivel grupal, más no así a nivel individual.     

The influence of cognitive emotion regulation strategies and depression severity on deliberate self-harm

Elaborating on previous studies on emotion regulation and deliberate self-harm (DSH), in the present study we distinguish between strategies of cognitive content (e.g., suicidal cognitions of perceived burdensomeness, helplessness, poor distress tolerance) and cognitive process (e.g., nonacceptance of emotional responses, lack of awareness of emotional responses). Young women who harmed themselves (n = 85) were compared with young women without a history of DSH (n = 93) across a broad range of strategies. Significant group differences were found for all measures, even when depression severity was controlled for. In addition, logistic regression analyses showed that both cognitive content strategies and cognitive process strategies made significant independent contributions to the prediction of group membership. Controlling for depression severity, suicidal cognitions, and nonacceptance of emotional responses independently predicted DSH. The strong association between suicidal cognitions and DSH seems to indicate the important role of these cognitions in recurrent and chronic DSH. The strong association between nonacceptance of emotional responses and DSH underscores the notion that DSH can be a way to avoid emotional problems. These findings are discussed in relation to recent cognitive-behavioral interventions and specific therapeutic techniques to further insight into how these interventions might work.     

Influences of target and nontarget shapes on target identification

The orientation of a nontarget in a location-cuing paradigm has been shown to affect accuracy of identification of target orientation when modified plus-signs (Ts) are the stimuli. In the current study, similar effects were found with Landolt C (C) stimuli. Both shapes of targets were identified by orientation. Moreover, targets were affected by nontargets whether both target and nontarget were the same shape or if they were different shapes. A single nontarget with an orientation that matched that of the target improved accuracy of identification of target orientation, whereas a nontarget with an orientation that did not match that of the target impaired accuracy of identification of target orientation, even though the nontargets appeared in locations that were never cued and could never contain targets. The data are consistent with either the Variable and Permeable Filters metaphor or a response competition account. Received: 1 July 1998 / Accepted: 22 October 1998     

Examining the effect of initialization strategies on the performance of Gaussian mixture modeling

Mixture modeling is a popular technique for identifying unobserved subpopulations (e.g., components) within a data set, with Gaussian (normal) mixture modeling being the form most widely used. Generally, the parameters of these Gaussian mixtures cannot be estimated in closed form, so estimates are typically obtained via an iterative process. The most common estimation procedure is maximum likelihood via the expectation-maximization (EM) algorithm. Like many approaches for identifying subpopulations, finite mixture modeling can suffer from locally optimal solutions, and the final parameter estimates are dependent on the initial starting values of the EM algorithm. Initial values have been shown to significantly impact the quality of the solution, and researchers have proposed several approaches for selecting the set of starting values. Five techniques for obtaining starting values that are implemented in popular software packages are compared. Their performances are assessed in terms of the following four measures: (1)?the ability to find the best observed solution, (2)?settling on a solution that classifies observations correctly, (3)?the number of local solutions found by each technique, and (4)?the speed at which the start values are obtained. On the basis of these results, a set of recommendations is provided to the user.     

To deliberate or not to deliberate: Interactions between age,task characteristics,and cognitive activity on decision making

The effects of aging and deliberative activities on decision making were examined. In two separate tasks, young, middle‐aged, and older adults were presented with four alternatives and given instructions to choose the best one. Following study, participants were either given additional time to think about their decision or were prevented from doing so. Decision quality did not benefit from additional deliberative activity when the structure of the stimuli facilitated fluent online processing. In contrast, deliberation promoted performance when such processing was more difficult. In addition, those individuals who focused on attribute information relevant to the decision context performed better than those who did not. Age differences in performance were minimal, but older adults with lower levels of education or cognitive ability tended to perform worse than the rest of the sample under conditions where deliberative skills were required to promote performance. The results are inconsistent with recent proposals regarding the benefits of passive deliberation. In addition, the results support the general assertion that the age effects in decision making will be most evident in situations dependent upon deliberative skills. Copyright © 2010 John Wiley & Sons, Ltd.     

The effect of organizational identification on employee affective and performance responses

Organizational identification (OI), defined as the importance of the organization in the person's self-concept, was argued to influence employee affective responses (job satisfaction and alienation) and performance responses (task involvement, investment of effort, and performance effectiveness). More specifically, it was hypothesized that there is 1. a positive relationship abetween OI and satisfaction with five job dimensions-work, supervision, pay, promotion and co-workers; 2. a negative relationship between OI and alienation; and 3. a positive relationship between OI and three task-related variables-task involvement, investment of effort, and performance effectiveness. A survey study was conducted on 215 service deliverers to the elderly in a large midwest city. The results were mostly consistent with the hypotheses.The data for this study was collected under the auspices of theBenjamin Rose Institute, Cleveland, Ohio.     

Aging and memory for new associations: direct versus indirect measures.

Three experiments examined adult age differences in memory for new associations between unrelated words. On the indirect (word-stem completion) test, age differences appeared under the less-than-optimal study conditions of Experiments 1 and 3 but not under the self-paced study conditions of Experiment 2. In contrast, all experiments revealed significant age-related deficits on the direct tests, even those (word-stem cued recall) in which the cue was identical to those provided on the indirect test. The findings show that although age-related deficits in memory for new associations are particularly pronounced on tests requiring conscious recollection, age differences are not limited to such tests. Age deficits on both direct and indirect tests are related to the precision of elaborations produced during study. Similarities and differences between normal aging and amnesia are discussed, as are functional dissociations between direct and indirect measures.