Patterns and temporal changes in peer affiliation among aggressive and nonaggressive children participating in a summer school program

Examined the behavior and affiliation patterns of 118 highly, moderately, and nonaggressive 7-year-old children over the course of a 6-week summer school program. During free play, participants did not selectively associate on the basis of behavioral similarity, but initial mutual friendship choices did show a preference for similarly behaved peers. Nonreciprocated friendships at the beginning and end of the program and mutual friendships at the end revealed a preference of all children to be-friend nonaggressive peers. Moderately aggressive children increased their number of mutual friendships and their association with nonaggressive peers during free play, whereas highly aggressive children lost mutual friends. The aggressiveness of a child's playmates predicted the likelihood of that child behaving inappropriately during free play. Results suggest that selective affiliation may be the result of peer rejection rather than an active process of seeking similarly aggressive peers.     

How to Assess a Model's Testability and Identifiability

Formal definitions are given of the following intuitive concepts: (a) A model is quantitatively testable if its predictions are highly precise and narrow. (b) A model is identifiable if the values of its parameters can be ascertained from empirical observations. (c) A model is redundant if the values of some parameters can be deduced from others or if the values of some observables can be deduced from others. Various rules of thumb for nonredundant models are examined. The Counting Rule states that a model is quantitatively testable if and only if it has fewer parameters than observables. This rule can be safely applied only to identifiable models. If a model is unidentifiable, one must apply a generalization of the Counting Rule known as the Jacobian Rule. This rule states that a model is quantitatively testable if and only if the maximum rank (i.e., the number of linearly independent columns) of its Jacobian matrix (i.e., the matrix of partial derivatives of the function that maps parameter values to the predicted values of observables) is smaller than the number of observables. The Identifiability Rule states that a model is identifiable if and only if the maximum rank of its Jacobian matrix equals the number of parameters. The conclusions provided by these rules are only presumptive. To reach definitive conclusions, additional analyses must be performed. To illustrate the foregoing, the quantitative testability and identifiability of linear models and of discrete-state models are analyzed. Copyright 2000 Academic Press.     

School-Based Secondary Prevention for Children with Disruptive Behavior: Initial Outcomes

First through fourth graders from 22 suburban elementary schools were screened for cross-setting disruptive behavior as eligibility criteria for participation in a longitudinal secondary prevention study aimed at reducing the risk for serious externalizing behavioral disorders. Three hundred nine subjects participated in either a multicomponent competence enhancement intervention (MCEI) or an information/attention control (IAC) condition over a 2-year period. Following baseline measurements, initial intervention effects were assessed at the end of intervention Year 1, at the beginning of intervention Year 2 (fall of the next school year), and at the end of intervention Year 2. Multisource assessments were not supportive of the efficacy of the MCEI over the IAC condition. Children in both groups rated themselves as improved over time in terms of increased adaptive skills and decreased school problems and internalizing symptoms. Teacher and parent ratings of externalizing behavior did not yield evidence of positive change, but teachers noted improved problem solving and observers noted a decrease in behavioral interference in both groups over time, possibly as a result of maturation.     

Relationship Quality of Aggressive Children and Their Siblings: A Multiinformant, Multimeasure Investigation

Sibling influence on the learning and enactment of aggressive behavior has been consistently demonstrated in studies of sibling relationships. Available evidence suggests that, compared with nonaggressive children's sibling interactions, the sibling interactions of aggressive children are marked by more frequent, intense, and prolonged aggressive behaviors. Although research on normative and aggressive children's sibling interactions has increased recently, a number of limitations in this literature were addressed in this study by: (1) including both an aggressive and nonaggressive comparison group, (2) examining both positive and negative features of sibling relationships, (3) employing a multimethod/multiinformant approach to data collection, and (4) utilizing an improved self-report method. In support of our hypotheses and consistent with previous research, results showed that aggressive children's sibling relationships were marked by higher levels of observed conflict and lower levels of self-reported positive features. When gender was examined, results showed that older brother/younger sister dyads were characterized by higher levels of negative features and lower levels of positive features.     

The Effects of Media Bias

The current research investigated whether bias exists in newspapers that are considered liberal or conservative, and whether this bias influences public opinion of events. Participants were college students ( N  = 67) who were enrolled in a 4-year university ( n  = 33) or a community college ( n  = 34). Participants were shown photographs and short articles relating to a presidential debate between President George W. Bush and Senator John Kerry. Participants completed questionnaires relating to their opinions of the candidates. Results showed statistical significance within groups before and after exposure to the newspaper clippings.     

Executive Functioning as a Mediator of Conduct Problems Prevention in Children of Homeless Families Residing in Temporary Supportive Housing: A Parallel Process Latent Growth Modeling Approach

A culturally diverse sample of formerly homeless youth (ages 6–12) and their families (n?=?223) participated in a cluster randomized controlled trial of the Early Risers conduct problems prevention program in a supportive housing setting. Parents provided 4 annual behaviorally-based ratings of executive functioning (EF) and conduct problems, including at baseline, over 2 years of intervention programming, and at a 1-year follow-up assessment. Using intent-to-treat analyses, a multilevel latent growth model revealed that the intervention group demonstrated reduced growth in conduct problems over the 4 assessment points. In order to examine mediation, a multilevel parallel process latent growth model was used to simultaneously model growth in EF and growth in conduct problems along with intervention status as a covariate. A significant mediational process emerged, with participation in the intervention promoting growth in EF, which predicted negative growth in conduct problems. The model was consistent with changes in EF fully mediating intervention-related changes in youth conduct problems over the course of the study. These findings highlight the critical role that EF plays in behavioral change and lends further support to its importance as a target in preventive interventions with populations at risk for conduct problems.