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Abstract
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PURPOSE: To assess changes in aggressive behaviors as related to progression from early to late puberty in normal adolescents. METHODS: Subjects were normal English schoolchildren. An observational cohort design was employed. Pubertal status was measured by Tanner staging. Self-reports of verbal aggression against adults, physical aggression against peers, aggressive impulses and aggressive inhibitory responses, were collected at three points in time. Analyses were performed for the entire group of 106 subjects in 1983, 77 subjects in 1985 and 70 subjects in 1987. Statistical methods included analysis of variance, regression and correlation and cluster formation. RESULTS: There were decreases in all aggression variables except in aggressive impulses over this time period. When analyzed by gender, boys were initially more aggressive than girls, but by late puberty all gender differences in self-reported aggressive behaviors had disappeared. When only those subjects who were evaluated at all three data collection times were grouped by similar responses on both aggression and physical variables, three clusters of boys and girls were identified. Clusters contained varying proportions of boys and girls. Cluster one (48.5% of the entire sample) was a low aggression group. Cluster two (30.3%) was a high aggression group, and cluster three (21.2%) was an intermediate aggression group. These clusters seemed to have relatively stable aggression characteristics over time. CONCLUSIONS: These data suggest that groups of boys and girls who report similar aggression characteristics and have similar growth and pubertal characteristics can be identified. Neither gender alone, nor pubertal status alone, nor by inference, hormones alone is sufficient to explain the complex set of behaviors which are involved in aggression.
VioLit summary:
OBJECTIVE:
The aim of this study by Finkelstein et al. was to evaluate the changes in aggressive behaviors that occur between early to late puberty in normal adolescents.
METHODOLOGY:
The authors conducted a quasi-experimental analysis of longitudinal data that were collected from Caucasian children in Southwestern England. These subjects were part of a longitudinal study of growth and development that commenced two years prior to this study. Subject selection was based on attendance at a single, State school and no exclusion criteria was involved. Data collection was conducted on the same group of individuals. Of the original sample, a number of subjects withdrew from the study throughout this period. Data were collected from 106 subjects in Spring, 1983; 77 subjects in Spring, 1985; and 70 subjects in Spring, 1987. Analyses of variance indicated no significant differences in self-reported aggressive behavior between those who remained in the research study and those who withdrew. Sexual maturity assessment was conducted using Tanners method of describing pubertal staging. This method essentially measures the physical maturity (e.g., rates of pubic hair development, females' breast development and males' genital development) of each individual and assigns a pubertal status label to their stage of development. Aggressive behaviors were measured using the Olweus Multifaceted Aggression Inventory. This inventory was employed to measure self-reports of verbal aggressiveness against adults; physical aggressiveness against peers; aggressive impulses and aggressive inhibitory responses. The authors reported that validity/reliability statistics were described by Olweus (1988). The authors conducted analyses of variance, regression and correlation, and cluster analyses to analyze the data.
FINDINGS/DISCUSSION:
The authors reported that aggressive impulses for both the boys and girls in this study did not change over time. Self-reports of verbal aggression against adults increased significantly, and there was a slight, though significant, decrease in self-reported physical aggression and aggressive inhibitory responses across the observation period. Tanner's pubertal staging scores and weight and height scores, increased steadily over the entire early to late puberty period. The authors stated that decreases in physical aggression were difficult to interpret since these results were inconsistent with other reports of increasing violence in youth. The authors attributed this finding as possibly due to variability within the sample. Data collected in 1983 revealed gender differences in self-reported aggressive behaviors. Boys were found to exhibit significantly greater levels of self-reported aggressive behavior than girls (e.g., verbal aggression against adults, p=.006; physical aggression against peers, p<.001). Girls exhibited higher aggression inhibition (p<.01). However, by late puberty this gender difference in self-reported aggressive behaviors had disappeared. The authors stated that this finding argued against reports that during puberty, hormones contribute towards gender differences in aggressive behavior. Cluster analyses identified three separate clusters of boys and girls. Each cluster displayed similar aggressive attributes. The authors reported that the general character of the clusters remained relatively stable across the time period of this study. Low Aggression scores revealed that cluster No.1 containing 42.8% boys and 52.6% girls, represented a low aggression group. The mean was 18.17 vs. 20.76; p=.05 from 1985 to 1987 for verbal aggression against adults, and there was a linear increase in aggressive impulses; mean was 13.83 vs 15.45 vs 14.10 for 1983, 1985 and 1987 respectively, p=0,047. Cluster No.2 consisting of 53.6% boys and 13.2% girls, represented the high aggression group, however, the aggression decreased over time. Physical aggression against peers decreased (means were 32.06 in 1983, 23.53 in 1985; p<.001, and 19.47 in 1987; p<.027). Aggressive impulses revealed a similar trend (means were 21.06, 20.29 and 17.77; p=0.027). There were no significant differences for verbal aggression against adults or aggressive inhibitory responses. Cluster No.3 was identified as an intermediate aggression group consisting of 3.6% boys and 34.2% girls. Means at the three points of data collection were 17.08, 18.67 and 19.33 (p=.018). The increase between 1983 and 1985 was significant (p=.037), however, between 1985 and 1987 it was not (p=.214). There was an interaction with gender (p=.019), however, the authors reported that this cluster consisted of only 13 girls and 1 boy thereby constraining interpretation of the results. There were no significant trends or differences in aggressive impulses or verbal aggression for this cluster.
It was reported that the majority of boys fell into the high aggression group in which physical aggression was the mode of aggressive behavior. Girls fell into the low to intermediate aggression groups. The mode of female aggression was verbal. The authors claimed that the inconsistency in gender differences between the cluster results and gender analysis suggests that the relationship between gender and aggressive behavior is very complex. The authors stated that an understanding of gender differences in self-reported aggression cannot be obtained by simply clustering subjects by gender.
The authors concluded that, although small, significant differences in aggressive behavior by self-report do exist in the subject pool over the course of puberty.
AUTHORS' RECOMMENDATIONS:
The authors suggested that longitudinal studies of normal adolescents that aim to identify the role of factors in adolescent aggression development need to account for several factors. These included: several methods for measuring aggressive behavior; methods for directly measuring the concentration of hormones in urine and blood; assessment of environmental effects; and physical puberty assessment.
(CSPV Abstract - Copyright © 1992-2007 by the Center for the Study and Prevention of Violence, Institute of Behavioral Science, Regents of the University of Colorado)
1980s
Child Aggression
Juvenile Aggression
Late Childhood
Early Adolescence
Countries Other Than USA
England
Longitudinal Studies
Child Development
Youth Development
Juvenile Development
Biological Factors
Aggression Causes
Gender Differences
Male Aggression
Female Aggression
Child Female
Child Male
Juvenile Female
Juvenile Male
Puberty
Language: en |