Heterogeneous heterogeneity by default: Testing categorical moderators in mixed-effects meta-analysis

Categorical moderators are often included in mixed-effects meta-analysis to explain heterogeneity in effect sizes. An assumption in tests of categorical moderator effects is that of a constant between-study variance across all levels of the moderator. Although it rarely receives serious thought, there can be statistical ramifications to upholding this assumption. We propose that researchers should instead default to assuming unequal between-study variances when analysing categorical moderators. To achieve this, we suggest using a mixed-effects location-scale model (MELSM) to allow group-specific estimates for the between-study variance. In two extensive simulation studies, we show that in terms of Type I error and statistical power, little is lost by using the MELSM for moderator tests, but there can be serious costs when an equal variance mixed-effects model (MEM) is used. Most notably, in scenarios with balanced sample sizes or equal between-study variance, the Type I error and power rates are nearly identical between the MEM and the MELSM. On the other hand, with imbalanced sample sizes and unequal variances, the Type I error rate under the MEM can be grossly inflated or overly conservative, whereas the MELSM does comparatively well in controlling the Type I error across the majority of cases. A notable exception where the MELSM did not clearly outperform the MEM was in the case of few studies (e.g., 5). With respect to power, the MELSM had similar or higher power than the MEM in conditions where the latter produced non-inflated Type 1 error rates. Together, our results support the idea that assuming unequal between-study variances is preferred as a default strategy when testing categorical moderators.     

The paradox of preference for unreliable reinforcement: The role of context and conditioned reinforcement

We discuss Belke and Spetch's (1994) work on choice between reliable and unreliable reinforcement. The studies by Belke and Spetch extend a line of basic research demonstrating that under certain experimental conditions in a concurrent chains procedure, pigeons prefer an alternative that produces unreliable reinforcement. The authors describe the variables that influence preference for unreliable reinforcement, including the signaling and the duration of the reinforcement schedules, the context in which the signaling stimuli occur, and the effects of conditioned reinforcement. Hypothetical applied examples that address these variables are provided, and their influence on preference for unreliable reinforcement in humans is discussed. We conclude by suggesting a line of applied research to examine the relationship between these variables and a preference for unreliable reinforcement.     

A behavioral assessment scale for attention deficit disorder in brazilian children based on DSM-IIIR criteria

A teacher scale based on DSM-III-R diagnostic criteria for attention deficit hyperactivity disorder (ADHD) was developed for the behavioral assessment of children in Brazil. A total of 2, 082 children (782 males and 1,300 females) with a mean age of 11.2 years who were attending a public school in the greater Rio de Janeiro area were the subjects of this study. Two factors (Hyperactivity-Impulsivity and Inattention) were extracted from a principal-factor analysis conducted on the data, and the factor structure of the scale was found to be stable. Ratings of boys were higher than ratings of girls, and younger children had higher ratings than older children for both factors. Test-retest reliability for each item of the scale ranged from .56 to .70. The data are discussed in view of current controversies in the factor structure of teacher ratings of DSM-III-R ADHD symptoms.This research was supported by FINEP (42.88.0138.00) and FUNPENE. GNOB is the recipient of a CNPq Research Career Development Award (30.0197/82). RCAP was supported by a CNPq fellowship (82.2151/87). The authors are grateful to Rosely V. Magalhaes and Angela S. Guedes for assistance in data analysis with the SAS and SPSS packages. The authors wish to thank the school staff and teachers who participated in the study. This work was presented at the Fifteenth European Conference of the International Neuropsychological Society, Portugal, 1993.     

How expert witnesses' counterfactuals influence causal and responsibility attributions of mock jurors and expert judges

Past research has shown that counterfactual (“If…then…”) thoughts influence causal and responsibility attribution in the judicial context. However, little is known on whether and how the use of counterfactuals in communication affects lay jurors' and judges' evaluations. In two studies, we asked mock lay jurors (Study 1) and actual judges (Study 2) to read a medical malpractice case followed by an expert witness report, which included counterfactuals focused on either the physician, the patient, or external factors. Results showed that counterfactual focus had a strong effect on both lay jurors' and judges' causal and responsibility attributions. Counterfactual focus also moderated the effect of outcome foreseeability on responsibility attribution. Discussion focuses on how counterfactual communication can direct causal and responsibility attribution and reduce the importance of other factors known to influence judicial decision‐making. The potential implications of these findings in training programs and debiasing interventions are also discussed.     

Interpersonal Psychotherapy—Adolescent Skills Training With Youth From Asian American and Immigrant Families: Cultural Considerations and Intervention Process

Although research has identified effective evidence-based depression prevention interventions for diverse youth, little is known about how the intervention process unfolds with immigrant family youth. This study utilized a qualitative approach to explore cultural and clinical differences in the implementation of Interpersonal Psychotherapy–Adolescent Skills Training (IPT-AST) in two schools, one serving youth from primarily immigrant, Asian American families and the second, youth from mostly nonimmigrant, non-Hispanic White families. A total of 131 IPT–AST sessions were audio recorded, transcribed, and coded for presence and patterns of cultural and clinical constructs. Results revealed that sessions with immigrant family youth were more likely to contain discussions of interpersonal problems characterized by estrangement, goals of spending time together with important others, mentions of emotion suppression and academic achievement expectations, conversations about acculturation, differences in value orientation, and discomfort with implementing new intervention skills. Dialogue from interventionist and youth exchanges is presented to illustrate how these themes emerged and were addressed by interventionists in a culturally responsive manner. The study highlights how IPT–AST with immigrant family and Asian American youth may unfold differently compared to youth from nonimmigrant families. Implications of findings for providers are discussed.     

Assessment and treatment of elopement maintained by chase

Elopement can have serious or fatal consequences associated with leaving the presence of an adult or getting lost (e.g., traffic injury and drowning). Given the dangers associated with elopement, caregivers are likely to chase after their child when elopement occurs. Like other forms of attention that follow problem behavior, chasing and retrieving the child may serve as a reinforcer and therefore maintain elopement. However, no study to date has evaluated whether elopement is sensitive to positive reinforcement in the form of chase. We evaluated the effects of chase on elopement with an 8‐year old boy diagnosed with autism. Elopement was maintained, at least in part, by chase. We then conducted a treatment evaluation in which we tested the effects of various antecedent‐ and consequence‐based treatment components within a multiple schedule.     

Understanding of the concept of numerically "less" by bottlenose dolphins (Tursiops truncatus)

In 2 experiments, bottlenose dolphins (Tursiops truncatus) judged the ordinal relationship between novel numerosities. The dolphins were first trained to choose the exemplar with the fewer number of items when presented with just a few specific comparisons (e.g., 2 vs. 6, 1 vs. 3, and 3 vs. 7). Generalization of this rule was then tested by presenting the dolphins with all possible pairwise comparisons between 1 and 8. The dolphins chose the exemplar with the fewer number of items at levels far above chance, showing that they could recognize and represent numerosities on an ordinal scale. Their pattern of errors was consistent with the idea of an underlying analog magnitude representation.     

How do memory systems interact? Evidence from human classification learning

Studies of human classification learning using functional neuroimaging have suggested that basal ganglia and medial temporal lobe memory systems may interact during learning. We review these results and outline a set of possible mechanisms for such interactions. Effective connectivity analyses suggest that interaction between basal ganglia and medial temporal lobe are mediated by prefrontal cortex rather than by direct connectivity between regions. A review of possible neurobiological mechanisms suggests that interactions may be driven by neuromodulatory systems in addition to mediation by interaction of inputs to prefrontal cortical neurons. These results suggest that memory system interactions may reflect multiple mechanisms that combine to optimize behavior based on experience.     

Gender and culture differences in emotion

In this article, the authors report a secondary analysis on a cross-cultural dataset on gender differences in 6 emotions, collected in 37 countries all over the world. The aim was to test the universality of the gender-specific pattern found in studies with Western respondents, namely that men report more powerful emotions (e.g., anger), whereas women report more powerless emotions (e.g., sadness, fear). The authors expected the strength of these gender differences to depend on women's status and roles in their respective countries, as operationalized by the Gender Empowerment Measure (GEM; United Nations Development Programme Human Development Report 2002). Overall, the gender-specific pattern of women reporting to experience and express more powerless emotions and men more powerful emotions was replicated, and only some interactions with the GEM were found.