Functions of aggressive behavior and future functional impairment

The present study investigated relations between proactive and reactive functions of physical and relational aggression and functional impairment across early childhood. It was hypothesized that reactive functions of aggression would be associated with functional impairment. Hypotheses with regard to proactive functions of aggression were exploratory. Participants were 36 children (22 girls) from a longitudinal study. At Time 1 (M = 50.31 months old, SD = 10.97), observations of aggressive behavior were collected during preschool free-play. At Time 2 (M = 73.33 months old, SD = 10.88), parent-report of functional impairment was collected. Reactive physical aggression was a significant and unique predictor of future impairment when controlling for gender and all other types of aggression. Implications of these findings are discussed from a developmental perspective.     

Sweat lactate response during cycling at 30°C and 18°C WBGT

Sweat lactate reflects eccrine gland metabolism. However, the metabolic tendencies of eccrine glands in a hot versus thermoneutral environment are not well understood. Sixteen male volunteers completed a maximal cycling trial and two 60-min cycling trials [30°C?=?30±1°C and 18°C?=?18±1°C wet bulb globe temperature (WBGT)]. The participants were requested to maintain a cadence of 60 rev?·?min^?1 with the intensity individualized at ～ 90% of the ventilatory threshold. Sweat samples at 10, 20, 30, 40, 50 and 60?min were analysed for lactate concentration. Sweat rate at 30°C (1380±325?ml?·?h^?1) was significantly greater (P<0.05) than at 18°C (632±311?ml?·?h^?1). Sweat lactate concentration was significantly greater (P<0.05) at each time point during the 18°C trial, with values between trials tending to converge across time. During the 30°C trial, both heart rate (20, 30, 40, 50 and 60?min) and rectal temperature (30, 40, 50 and 60?min) were significantly higher than in the 18°C trial. Higher sweat lactate concentrations coupled with lower sweat rates may indicate a greater relative contribution of oxygen-independent metabolism within eccrine glands during exercise at 18°C. Decreases in sweat lactate concentration across time suggest either greater dilution due to greater sweat volume or increased reliance on aerobic metabolism within eccrine glands. The convergence of lactate concentrations between trials may indicate that time-dependent modifications in sweat gland metabolism occur at different rates contingent partially on environmental conditions.     

A Longitudinal Study of Forms and Functions of Aggressive Behavior in Early Childhood

The purpose of this study was to investigate the distinct forms (i.e., physical and relational) and functions (i.e., proactive and reactive) of aggressive behavior during early childhood ( n  =   101; M age = 45.09 months). Forms, but not functions, of aggressive behavior were stable over time. A number of contributors to aggression were associated with distinct subtypes of aggressive behavior. Females and socially dominant children were more relationally aggressive and older children were less physically aggressive than their peers. Longitudinal analyses indicated that social dominance predicted decreases in physical aggression and peer exclusion predicted increases in relational aggression. Overall, the results provide support for the distinction between subtypes of aggression in early childhood.     

The Reciprocal Relations Between Female and Male Play Partners and Aggression in Early Childhood

This study examined the relations between male and female play partners (PP) and relational (RA) and physical (PA) aggression in an early childhood short-term longitudinal study (N = 164, M_age = 47.11 months, SD = 7.37 months). A cross-lagged path analysis was used to examine these relations from Time 1 (T1) to Time 2 (T2), 4 months after T1, and a multiple group analysis was tested across gender. Results showed that T1 male PP predicted an increase in PA, T1 RA predicted an increase in female PP, and T1 PA predicted a decrease in female PP. One path was not equivalent across gender. A post hoc interaction between male and female PP at T1 on future RA was evaluated.     

Prospective associations between peer victimization and aggression

The current study involved a short-term longitudinal study of young children (M = 44.56 months, SD = 11.88, N = 103) to test the prospective associations between peer victimization and aggression subtypes. Path analyses documented that teacher-reported physical victimization was uniquely associated with increases in observed physical aggression over time. The path model also revealed that teacher-reported relational victimization was uniquely associated with statistically significant increases in observed relational aggression over time. Ways in which these findings extend the extant developmental literature are discussed.     

An intervention for relational and physical aggression in early childhood: A preliminary study

A preventive intervention for reducing physical and relational aggression, peer victimization, and increasing prosocial behavior was developed for use in early childhood classrooms. Nine classrooms were randomly assigned to be intervention rooms (N = 202 children) and nine classrooms were control rooms (N = 201 children). Classroom was the unit of analysis and both observations and teacher-reports were obtained at pre and post-test. Focus groups were used to develop the initial program. The 6-week program consisted of developmentally appropriate puppet shows, active participatory sessions, passive concept activities and in vivo reinforcement periods. Preliminary findings suggest that the “Early Childhood Friendship Project” tended to reduce physical and relational aggression, as well as physical and relational victimization and tended to increase prosocial behavior more for intervention than control classrooms. Teachers and interventionists provided positive evaluations of the program and there is evidence for appropriate program implementation.     

Relational Aggression and Friendship During Early Childhood: I Won't Be Your Friend!

Associations between relational aggression and mutual, dyadic friendships during early childhood were assessed in the context of a year-long, short-term longitudinal study. Children's mutual friendships were determined via sociometric ratings and their relationally aggressive behavior among peers was assessed via naturalistic, free play observations. Generally, children who were more relationally aggressive had more mutual friends, although this relation differed by gender and time of assessment. Future work should include measures of friendship quality and investigate the role of relational aggression within friendship dyads.