Imitative Aggression with Adult Male and Female Models in Father Absent and Father Present Negro Boys

Summary

Young Negro boys from father present and father absent homes showed similar aggressive behavior after viewing films of Negro adult male or female models behaving aggressively. In a control condition father present and absent boys showed similar aggressive behavior without seeing any film. For both groups of boys, there was significantly less aggression in the female model condition than in either the male model or the control, no model conditions, suggesting an inhibitory effect of the female model.     

A Class of Probabilistic Unfolding Models for Polytomous Responses

By revisiting the approaches used to present the Rasch model for polytomous response, this paper uses the principle of the rating formulation (Andrich, 1978) to construct a class of unfolding models for polytomous responses in terms of a set of latent dichotomous unfolding variables. By anchoring the dichotomous unfolding variables involved at the same location, this paper presents a formulation of a very general class of unfolding models for ordered polytomous responses, of which the unfolding models for ordered polytomous responses proposed hitherto are special cases. Within this class, the analytic and measurement properties of the probabilistic functions are well interpreted in terms of the latitudes of acceptance parameters of the dichotomous unfolding models. Based on the general form of this class of unfolding models, some new models are readily specified. Copyright 2001 Academic Press.     

A Class of Distribution-Free Models for Longitudinal Mediation Analysis

Mediation analysis constitutes an important part of treatment study to identify the mechanisms by which an intervention achieves its effect. Structural equation model (SEM) is a popular framework for modeling such causal relationship. However, current methods impose various restrictions on the study designs and data distributions, limiting the utility of the information they provide in real study applications. In particular, in longitudinal studies missing data is commonly addressed under the assumption of missing at random (MAR), where current methods are unable to handle such missing data if parametric assumptions are violated. In this paper, we propose a new, robust approach to address the limitations of current SEM within the context of longitudinal mediation analysis by utilizing a class of functional response models (FRM). Being distribution-free, the FRM-based approach does not impose any parametric assumption on data distributions. In addition, by extending the inverse probability weighted (IPW) estimates to the current context, the FRM-based SEM provides valid inference for longitudinal mediation analysis under the two most popular missing data mechanisms; missing completely at random (MCAR) and missing at random (MAR). We illustrate the approach with both real and simulated data.     

The Role of Relational Aggression in Identifying Aggressive Boys and Girls

Peer perceptions of relational and overt aggression and peer evaluations of social competencies were obtained for 461 boys and 443 girls in second and third grades. In contrast to Crick and Grotpeter (1995), boys obtained higher relational and overt aggression scores than girls, and the relation between both types of aggression and peer evaluations were similar for boys and girls. When controlling for levels of overt aggression, relational aggression made a statistically significant but small contribution to the prediction of both peer-evaluated competencies and teacher ratings of aggression in boys and girls. Analyses treating relational and overt aggression as categorical variables revealed gender differences in the prevalence and corresponding sociometric status of aggressive subtypes. When peer-rated relational aggression status is not considered, 60% of aggressive girls, compared to 7% of aggressive boys, are not identified as aggressive. High levels of overt aggression were more likely to result in peer rejection for girls than for boys. In a subsample of 112 children, peer-rated relational aggression contributed more to the discrimination of teacher-identified aggressive and nonaggressive girls, whereas peer-rated overt aggression contributed more to the discrimination of teacher-identified aggressive and nonaggressive boys.     

On Inclusion of Covariates for Class Enumeration of Growth Mixture Models

In this article, we directly question the common practice in growth mixture model (GMM) applications that exclusively rely on the fitting model without covariates for GMM class enumeration. We provide theoretical and simulation evidence to demonstrate that exclusion of covariates from GMM class enumeration could be problematic in many cases. Based on our findings, we provide recommendations for examining the class enumeration by the fitting model without covariates and discuss the potential of covariate inclusion as a remedy for the weakness of GMM class enumeration without including covariates. A real example on the development of children's cumulative exposure to risk factors for adolescent substance use is provided to illustrate our methodological developments.     

Inspiration From Role Models and Advice for Moving Forward

This Behavior Therapy series on overcoming the glass ceiling followed from a highly attended panel at ABCT on the same topic. The current paper summarizes the common themes across the various papers in this series with respect to obstacles prominent women have faced, and how we can learn from their stories to help inform the future. These themes include the importance of role models, messages from a supportive environment, difficulties balancing careers with children, coordinating careers with family, importance of taking charge of one's career, moving forward despite negative internal and external messages, and questions about whether things have changed substantially. In addition, this paper contains a summary of the helpful advice from accomplished women in academia for navigating the academic waters. It is our aspiration that going forward this series will stimulate other conversations as well as increase thought, behavior, solidarity, and awareness about this topic so that we can continue to work toward a future when things will continue to improve for women.     

A Longitudinal Investigation of Gender Role and Muscle Building in Adolescent Boys

Boys’ use of muscle building techniques during early adolescence is poorly understood. The present study investigated the impact of gender role intensification, investment in muscular media images, appearance social comparison, and attitudes concerning muscularity on the use of muscle building techniques. Middle school boys (N?=?143; M _age?=?12.92 years) from the Midwestern United States completed questionnaires. They were re-assessed 7 months later. Structural equation modeling indicated that gender role intensification as well as Time 1 media investment, and social comparison predicted Time 2 media investment in the muscular ideal which was in turn correlated with Time 2 muscle building. Implications for prevention of body image problems and muscle building among boys are discussed.     

Stepwise Latent Class Models for Explaining Group-Level Outcomes Using Discrete Individual-Level Predictors

Explaining group-level outcomes from individual-level predictors requires aggregating the individual-level scores to the group level and correcting the group-level estimates for measurement errors in the aggregated scores. However, for discrete variables it is not clear how to perform the aggregation and correction. It is shown how stepwise latent class analysis can be used to do this. First, a latent class model is estimated in which the scores on a discrete individual-level predictor are used to construct group-level latent classes. Second, this latent class model is used to aggregate the individual-level predictor by assigning the groups to the latent classes. Third, a group-level analysis is performed in which the aggregated measures are related to the remaining group-level variables while correcting for the measurement error in the class assignments. This stepwise approach is introduced in a multilevel mediation model with a single individual-level mediator, and compared to existing methods in a simulation study. We also show how a mediation model with multiple group-level latent variables can be used with multiple individual-level mediators and this model is applied to explain team productivity (group level) as a function of job control (individual level), job satisfaction (individual level), and enriched job design (group level).     

Bayesian Inference for Growth Mixture Models with Latent Class Dependent Missing Data

Growth mixture models (GMMs) with nonignorable missing data have drawn increasing attention in research communities but have not been fully studied. The goal of this article is to propose and to evaluate a Bayesian method to estimate the GMMs with latent class dependent missing data. An extended GMM is first presented in which class probabilities depend on some observed explanatory variables and data missingness depends on both the explanatory variables and a latent class variable. A full Bayesian method is then proposed to estimate the model. Through the data augmentation method, conditional posterior distributions for all model parameters and missing data are obtained. A Gibbs sampling procedure is then used to generate Markov chains of model parameters for statistical inference. The application of the model and the method is first demonstrated through the analysis of mathematical ability growth data from the National Longitudinal Survey of Youth 1997 (Bureau of Labor Statistics, U.S. Department of Labor, 1997). A simulation study considering 3 main factors (the sample size, the class probability, and the missing data mechanism) is then conducted and the results show that the proposed Bayesian estimation approach performs very well under the studied conditions. Finally, some implications of this study, including the misspecified missingness mechanism, the sample size, the sensitivity of the model, the number of latent classes, the model comparison, and the future directions of the approach, are discussed.     

Latent Class Models for Diary Method Data: Parameter Estimation by Local Computations

The increasing use of diary methods calls for the development of appropriate statistical methods. For the resulting panel data, latent Markov models can be used to model both individual differences and temporal dynamics. The computational burden associated with these models can be overcome by exploiting the conditional independence relations implied by the model. This is done by associating a probabilistic model with a directed acyclic graph, and applying transformations to the graph. The structure of the transformed graph provides a factorization of the joint probability function of the manifest and latent variables, which is the basis of a modified and more efficient E-step of the EM algorithm. The usefulness of the approach is illustrated by estimating a latent Markov model involving a large number of measurement occasions and, subsequently, a hierarchical extension of the latent Markov model that allows for transitions at different levels. Furthermore, logistic regression techniques are used to incorporate restrictions on the conditional probabilities and to account for the effect of covariates. Throughout, models are illustrated with an experience sampling methodology study on the course of emotions among anorectic patients. Frank Rijmen was partly supported by the Fund for Scientific Research Flanders (FWO).     

New Models for Increasing Donor Awareness: The Role of Religion

Surgical clinical trials have seldom used a "sham" or placebo surgical procedure as a control, owing to ethical concerns. Recently, several ethical commentators have argued that sham surgery is either inherently or presumptively unethical. In this article I contend that these arguments are mistaken and that there are no sound ethical reasons for an absolute prohibition of sham surgery in clinical trials. Reflecting on three cases of sham surgery, especially on the recently reported results of a sham-controlled trial of arthroscopic surgery for arthritis of the knee, I present an ethical analysis that focuses on the methodological rationale for use of sham surgery, risk-benefit assessment, and informed consent.     

The Critical Mediating Role of Social Encouragement for Science Motivation and Confidence Among High School Girls and Boys1

Previous research has identified student status variables (gender, ability, and parent education level) and social influence variables (encouragement from family, teachers, and peers) as predictors of science attitudes. The present study tested the extent to which social encouragement mediates the relation between status variables and science motivation and confidence. In a sample of 184 senior high school students, social encouragement was a stronger predictor of science attitudes than status variables and mediated 72% of the variance in attitudes predicted by status variables. Encouragement from family, encouragement from teachers, and encouragement from peers were each independent predictors of science attitudes. The findings provide strong evidence of the critical importance of encouragement from social agents in the development of adolescents' motivation and confidence to achieve in science.     

Social Comparison and Body Image: Attractiveness Comparisons to Models and Peers Among Adolescent Girls and Boys

Relations among body image satisfaction and social comparisons to either same-sex peers or media models were examined in 2 studies of adolescent boys and girls. In the first study, 9th and 10th graders described their conceptions of attractiveness for same- and opposite-sex adolescents. These attractiveness attributes were then used in Study 2 in which 7th- and 10th-grade boys and girls reported on social comparisons to models/celebrities and same-sex peers. Body dissatisfaction was also assessed. The results confirmed that both same-sex peers and models/celebrities were the targets of social comparisons for physical attributes, but comparisons on personal and social attributes were more likely directed toward same-sex peers. For boys and girls, weight comparisons to both peer and model targets were primary correlates of body dissatisfaction. In addition, shape comparisons reported by the girls and facial comparisons endorsed by the boys also related to body dissatisfaction. Gender differences in social comparison indicated that girls reported more social comparisons across targets and attributes. Results are discussed in terms of the role of social comparison and peer context for body image during adolescence.     

The Role of Simple Emotion Recognition Skills among School Aged Boys at Risk of ADHD

Poor social skills and behavioral problems are a major component of ADHD. The different explanations offered so far, such as cognitive deficits and deficient self regulation, have not been able fully to account for the various aspects of the social dysfunction, suggesting that other mechanisms might underlay this impairment. Our study sought to assess the emotion recognition of Israeli boys at risk of ADHD, and to evaluate its associations with their social skills. A group of 111 boys (grades 4 and 5) were assigned to an At-risk (n=50) and a control (n=61) group based on their scores in an ADHD symptoms questionnaire. The two groups were matched on age, socio-economic status and class and school environment. Group comparisons revealed that compared to their non-At-risk counterparts, At-risk boys have impaired emotion recognition. Finally, multiple groups Structural Equation Modeling analyses (SEM) demonstrated that emotion misrecognition plays a significant role in the At-risk children's social functioning and behavioral problems compared to its role in the social competence and behavioral problems among the comparison group. Implications for the understanding and treatment of social skills problems among children at risk of ADHD are proposed.     

Characteristics of Role Models for Young African-American Men: An Exploratory Survey

Recognized leaders of African-American communities were surveyed with 24 items developed by the investigators to aid in the identification of pertinent characteristics common to successful and positive role models for young African-American men.     

Simultaneous Decision on the Number of Latent Clusters and Classes for Multilevel Latent Class Models

The Multilevel Latent Class Model (MLCM) proposed by Vermunt (2003) has been shown to be an excellent framework for analyzing nested data with assumed discrete latent constructs. The nonparametric version of MLCM assumes 2 levels of discrete latent components to describe the dependency observed in data. Model selection is an important step in any statistical modeling. The task of model selection for MLCM amounts to the decision on the number of discrete latent components at both higher and lower levels and is more challenging than standard Latent Class Models. In this article, simulation studies were conducted to systematically examine the effects of sample sizes, clusters/classes distinctness, and the number of latent clusters and classes on the performance of various information criteria in recovering the true latent structure. Results of the simulation studies are summarized and presented. The final section presents the remarks and recommendations about the simultaneous decision regarding the number of latent classes and clusters when applying MLCMs to analyze empirical data.     

Explaining with Models: The Role of Idealizations

Because they contain idealizations, scientific models are often considered to be misrepresentations of their target systems. An important question is therefore how models can explain the behaviours of these systems. Most of the answers to this question are representationalist in nature. Proponents of this view are generally committed to the claim that models are explanatory if they represent their target systems to some degree of accuracy; in other words, they try to determine the conditions under which idealizations can be made without jeopardizing the representational function of models. In this article, we first outline several forms of this representationalist view. We then argue that this view, in each of these forms, omits an important role of idealizations: that of facilitating the identification of the explanatory components within a model. Via examination of a case study from contemporary astrophysics, we show that one way in which idealizations can do this is by creating a comparison case that serves to highlight the relevant features of the target system.     

Drunken Role Models: Rescuing Our Sporting Exemplars

It is often claimed that elite professional athletes are role models and as such have certain duties to behave in morally appropriate ways. The argument is that given their influential status and influence, they should be good examples rather than bad ones. In relation to alcohol consumption and the problematic behaviours associated with excessive consumption, many professional athletes are bad role models. They consume too much and behave badly. Drawing on neo-Aristotelian insights I argue the following. First, persons who exhibit good character and virtues like self-control are preferable to those who exemplify vice like recklessness and selfishness in general and in relation to alcohol consumption in particular. To exhibit virtue is both good in itself and preferable from a moral education perspective. In other words it is better to exemplify virtue in front of others who may follow the example. Second, acting well and becoming the right sort is notoriously difficult and the moral atmosphere or the ethos of the culture in which virtue plays out has a significant impact. It is important therefore to include the ethos of sporting practice in any proposed reform of drinking behaviour such that tolerance and tacit promotion of masculine drinking practices is eschewed in favour of responsible and considerate consumption. Finally I argue that we must cultivate the proper virtue of emulation so that people who are admired or esteemed (sporting heroes) by young people in particular are not copied blindly. In other words it is important to cultivate a critical capacity to recognise worthy role models and to avoid identifying with unworthy characters, practices and vices. Part of this process is to highlight proper and worthy role models inside and outside of sport. In conclusion, I believe that although bad role models are grabbing the headlines in relation to problematic drinking practices, there are good role models in sport who should be lauded as exemplars of good character living a worthwhile sporting life. Such characters can show those inside and outside the practice community a more responsible and considerate approach to alcohol.