Charles M. Judd

When moderation is mediated and mediation is moderated.

Procedures for examining whether treatment effects on an outcome are mediated and/or moderated have been well developed and are routinely applied. The mediation question focuses on the intervening mechanism that produces the treatment effect. The moderation question focuses on factors that affect the magnitude of the treatment effect. It is important to note that these two processes may be combined in informative ways, such that moderation is mediated or mediation is moderated. Although some prior literature has discussed these possibilities, their exact definitions and analytic procedures have not been completely articulated. The purpose of this article is to define precisely both mediated moderation and moderated mediation and provide analytic strategies for assessing each.

Estimating and testing mediation and moderation in within-subject designs.

Analyses designed to detect mediation and moderation of treatment effects are increasingly prevalent in research in psychology. The mediation question concerns the processes that produce a treatment effect. The moderation question concerns factors that affect the magnitude of that effect. Although analytic procedures have been reasonably well worked out in the case in which the treatment varies between participants, no systematic procedures for examining mediation and moderation have been developed in the case in which the treatment varies within participants. The authors present an analytic approach to these issues using ordinary least squares estimation.

Definition and assessment of accuracy in social stereotypes

A perennial issue in the study of social stereotypes concerns their accuracy. Yet, there is no clear concept of the various ways in which stereotypes may be accurate or inaccurate and how one would assess their accuracy. This article is designed to rectify this situation. Three forms of stereotype inaccuracy are identified: stereotypic inaccuracy, valence inaccuracy, and dispersion inaccuracy. The implications of each form are discussed, along with how each can be assessed using a full-accuracy design. Past research that has attempted to examine stereotype accuracy is reviewed, and new data on the issue are presented. Although of perennial interest, the theoretical and methodological difficulties of assessing stereotype accuracy are substantial. The goal in this article is to alert the researcher to these difficulties and point toward their solution.

The Influence of Afrocentric Facial Features in Criminal Sentencing

Prior research has shown that within a racial category, people with more Afrocentric facial features are presumed more likely to have traits that are stereotypic of Black Americans compared with people with less Afrocentric features. The present study investigated whether this form of feature-based stereotyping might be observed in criminal-sentencing decisions. Analysis of a random sample of inmate records showed that Black and White inmates, given equivalent criminal histories, received roughly equivalent sentences. However, within each race, inmates with more Afrocentric features received harsher sentences than those with less Afrocentric features. These results are consistent with laboratory findings, and they suggest that although racial stereotyping as a function of racial category has been successfully removed from sentencing decisions, racial stereotyping based on the facial features of the offender is a form of bias that is largely overlooked.

Across the Thin Blue Line: Police Officers and Racial Bias in the Decision to Shoot

Police officers were compared with community members in terms of the speed and accuracy with which they made simulated decisions to shoot (or not shoot) Black and White targets. Both samples exhibited robust racial bias in response speed. Officers outperformed community members on a number of measures, including overall speed and accuracy. Moreover, although community respondents set the decision criterion lower for Black targets than for White targets (indicating bias), police officers did not. The authors suggest that training may not affect the speed with which stereotype-incongruent targets are processed but that it does affect the ultimate decision (particularly the placement of the decision criterion). Findings from a study in which a college sample received training support this conclusion.

Treating stimuli as a random factor in social psychology: a new and comprehensive solution to a pervasive but largely ignored problem.

Throughout social and cognitive psychology, participants are routinely asked to respond in some way to experimental stimuli that are thought to represent categories of theoretical interest. For instance, in measures of implicit attitudes, participants are primed with pictures of specific African American and White stimulus persons sampled in some way from possible stimuli that might have been used. Yet seldom is the sampling of stimuli taken into account in the analysis of the resulting data, in spite of numerous warnings about the perils of ignoring stimulus variation (Clark, 1973; Kenny, 1985; Wells & Windschitl, 1999). Part of this failure to attend to stimulus variation is due to the demands imposed by traditional analysis of variance procedures for the analysis of data when both participants and stimuli are treated as random factors. In this article, we present a comprehensive solution using mixed models for the analysis of data with crossed random factors (e.g., participants and stimuli). We show the substantial biases inherent in analyses that ignore one or the other of the random factors, and we illustrate the substantial advantages of the mixed models approach with both hypothetical and actual, well-known data sets in social psychology (Bem, 2011; Blair, Chapleau, & Judd, 2005; Correll, Park, Judd, & Wittenbrink, 2002).

The Role of Afrocentric Features in Person Perception: Judging by Features and Categories

Four studies were conducted to test the hypothesis that group-related physical features may directly activate related stereotypes, leading to more stereotypic inferences over and above those resulting from categorization. As predicted, targets with more Afrocentric features were judged as more likely to have traits stereotypic of African Americans. This effect was found with judgments of African Americans and of European Americans. Furthermore, the effect was not eliminated when a more sensitive measure of categorization processes (category accessibility) was used or when the judgement context made category distinctions salient. Of additional interest was the finding that category accessibility independently affected judgment, such that targets who could be more quickly categorized as group members were judged more stereotypically.

Stereotypes and ethnocentrism: diverging interethnic perceptions of African American and white American youth.

Much recent work on stereotyping has dealt with groups that are either artificially created or that do not have an extensive history of conflict. The authors attempted to overcome this limitation by examining issues of perceived variability and ethnocentrism among samples of White American and African American youth. The goals were both to examine theoretical issues in stereotyping and to describe the current state of ethnic interrelations among young people. Four studies are reported. Throughout, the samples of African Americans demonstrate interethnic judgments that are consistent with existing work on stereotyping and ethnocentrism. White American students, however, reported judgements that replicate neither the out-group homogeneity effect nor ethnocentrism. Alternative explanations for this difference are considered, and the discussion focuses on differing views concerning the role of ethnic identity and diversity in our society.

Proinflammatory cytokines oppose opioid-induced acute and chronic analgesia

Spinal proinflammatory cytokines are powerful pain-enhancing signals that contribute to pain following peripheral nerve injury (neuropathic pain). Recently, one proinflammatory cytokine, interleukin-1, was also implicated in the loss of analgesia upon repeated morphine exposure (tolerance). In contrast to prior literature, we demonstrate that the action of several spinal proinflammatory cytokines oppose systemic and intrathecal opioid analgesia, causing reduced pain suppression. In vitro morphine exposure of lumbar dorsal spinal cord caused significant increases in proinflammatory cytokine and chemokine release. Opposition of analgesia by proinflammatory cytokines is rapid, occurring < or =5 min after intrathecal (perispinal) opioid administration. We document that opposition of analgesia by proinflammatory cytokines cannot be accounted for by an alteration in spinal morphine concentrations. The acute anti-analgesic effects of proinflammatory cytokines occur in a p38 mitogen-activated protein kinase and nitric oxide dependent fashion. Chronic intrathecal morphine or methadone significantly increased spinal glial activation (toll-like receptor 4 mRNA and protein) and the expression of multiple chemokines and cytokines, combined with development of analgesic tolerance and pain enhancement (hyperalgesia, allodynia). Statistical analysis demonstrated that a cluster of cytokines and chemokines was linked with pain-related behavioral changes. Moreover, blockade of spinal proinflammatory cytokines during a stringent morphine regimen previously associated with altered neuronal function also attenuated enhanced pain, supportive that proinflammatory cytokines are importantly involved in tolerance induced by such regimens. These data implicate multiple opioid-induced spinal proinflammatory cytokines in opposing both acute and chronic opioid analgesia, and provide a novel mechanism for the opposition of acute opioid analgesia.

Rethinking the Link Between Categorization and Prejudice Within the Social Cognition Perspective

For the past 40 years, social psychological research on stereotyping and prejudice in the United States has been dominated by the social cognition perspective, which has emphasized the important role of basic categorization processes in intergroup dynamics. An inadvertent consequence of this approach has been a disproportionate focus on social categorization as a causal factor in intergroup animosity and, accordingly, an emphasis on approaches that minimize category distinctions as the solution to intergroup conflict. Though recognizing the crucial function of categorization, we question existing support for the hypothesis that the perception of strong group differences necessarily results in greater intergroup bias. Given that it is neither feasible nor ultimately desirable to imagine that social categories can be eliminated, we suggest that a more useful approach is one that promotes intergroup harmony even while recognizing and valuing the distinctions that define our social world.