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A developmental framework emphasizing the combined impact of correlated constraints within and without the individual was applied to a prospective longitudinal study of early parenthood. The purpose was to use a person-approach to the analysis of longitudinal data to clarify risk for early parenthood and to generate hypotheses about potentially useful intervention strategies. Respondents were 475 youth who were assessed annually from seventh grade through the end of high school and, again, at ages 20 and 24. The risk patterns associated with parenthood were the same for both sexes. Individuals with a middle-school configuration of low socioeconomic status, high aggression, low academic skills, low popularity, and prior grade failure were most likely to become parents by early adulthood. Risk for early parenthood increased substantially for respondents who dropped out of school early, regardless of their initial risk status.

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This research compared the social and cognitive development of young mothers when they were children with the social and cognitive development of their offspring. Intergenerational development was investigated over a 17-year period for 57 women who had been studied longitudinally from childhood to adulthood and who became young mothers (R. B. Cairns & B. D. Cairns, 1994). The children of these women, in turn, were followed prospectively from 1 to 2 years old through the early school years. The academic competence of mothers when they were children was significantly linked to the academic competence of their children at school age. In contrast, the across-generation correlations between measures of aggressive behavior of the mothers when they were children and measures of aggressive behavior of their children in early school grades were modest and unreliable. Certain within-generation continuities were observed in both cognitive and aggressive development.

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In a previous study, it was demonstrated that the high rates of social reactivity exhibited by isolated male mice in a dyadic encounter were mediated, at least in part, by an increased sensitivity of the D1 dopamine receptors. The present research was guided by the hypothesis that the behavioral effects of isolation are reversible, and that changes in dopaminergic function support this reversibility. To this end, mice selectively bred for high and low levels of aggression were reared in isolation from weaning (21 days) to puberty (45 days), at which point they were either assigned to groups or left in isolation until day 69. By comparison to the continuous isolation condition, mice that eventually formed groups exhibited significantly less reactivity in a dyadic test conducted on day 69, showed a reduced response to dihydrexidine (DHX), and a decreased density of D1 dopamine receptors. This experiment provided evidence for the plasticity of the neurobiological system supporting reactive responses, and confirmed the view that its functional organization is open to experientially-induced changes.

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This study examined the relation between involvement in school-based extracurricular activities and early school dropout. Longitudinal assessments were completed for 392 adolescents (206 girls, 186 boys) who were initially interviewed during 7th grade and followed up annually to 12th grade. A person-oriented cluster analysis based on Interpersonal Competence Scale ratings from teachers in middle schools (i.e., 7th-8th grades) identified configurations of boys and girls who differed in social-academic competence. Early school dropout was defined as failure to complete the 11th grade. Findings indicate that the school dropout rate among at-risk students was markedly lower for students who had earlier participated in extracurricular activities compared with those who did not participate (p < .001). However, extracurricular involvement was only modestly related to early school dropout among students who had been judged to be competent or highly competent during middle school.

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Genetic influences on the social behaviours of non-human mammals are ubiquitous, powerful and readily detected. But demonstrations that social behaviours are influenced by genes constitute only part of the story. Developmental findings have helped complete the picture. Specifically, these studies show that: (1) genetic effects for aggressive behaviours are highly malleable over the course of development; (2) genetic influences on aggressive behaviour are more dynamic, easily achieved and open to rapid manipulation than has been recognized in current models of social evolution and behavioural genetics; (3) developmental timing has a significant impact upon the nature of the genetic effects observed in aggressive behaviours. These empirical results are consistent with the view that social behaviours are among the first features to be influenced by genetic selection and by environmental experience. Social actions have distinctive properties in adaptation because they organize the space between the organism and the environment and promote rapid, selective and novel accommodations. The modern integrative view of the development of individual-in-context brings attention to the correlation between constraints within and external to individuals. This paper reviews findings on how these processes become integrated over time in individuals and species, and their implications for the nurture of nature.

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PURPOSE: This study examined the: (1) relationships among gender, race, and socioeconomic status and the incidence of adolescent injury and "close calls" (near accidents); (2) ability of childhood aggression to predict injury and "close calls" during adolescence; and (3) characteristics of injury and "close-call" events, including contributing mechanisms and risk-taking behaviors. METHODS: Subjects were a subsample (N = 271) of the Carolina Longitudinal Study who reported an injury (48%) or "close-call" (52%) during a 9th, 10th, or 11th grade interview (mean age 16.3 years); 52% were female and 23% African American. They were recruited beginning at grade 4 and grade 7 and were interviewed annually. RESULTS: More males than females reported an injury (chi 2 = 4.97, p < .05); motor vehicles and sports were major contributors. Caucasian females reported more injuries (chi 2 = 3.90, p < .05) and "close calls" (X2 = 4.13, p < .05) than African American females. More males than females reported risk-taking behaviors associated with injuries (chi 2 = 4.35, p < .05) and "close calls" (X2 = 4.29, p < .05), especially Caucasians. Logistic regression demonstrated that childhood aggression was a robust predictor of adolescent injury and "close calls." CONCLUSIONS: Reports of "close calls" by a majority of the sample suggest that mortality and morbidity statistics in this age group may underestimate the vulnerability of youth to serious injury. These results further add risk for physical injury in adolescence to the sequalae of childhood aggression. These findings suggest the need for the incorporation of injury prevention into school curriculum and activities of all children, but especially for children assessed as aggressive.

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Social networks and friendships were tracked over a 3-week period for 132 students enrolled in fourth- and seventh-grade classrooms. Individual interviews were employed to collect data on friendships. Social group membership was determined by the composite social-cognitive map (SCM) procedure and by self-reports. Considerable overlap was found among the methods for establishing relational patterns (i.e., friendships, self-reported groups, composite social-cognitive maps). When loose criteria for stability were employed, high stability was found in friendships (p = .56-.75) and social group membership (p = .90) over a 3-week period. But when stringent criteria were employed, only modest social relationship stability was observed in both methods, suggesting that there is much greater fluidity in peer bonds than has been generally recognized. The relationship between friendship and social network measures, the distinctive information yielded by social networks, and gender and age differences in group structure, fluidity, and friendships are discussed.

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The Interpersonal Competence Scale (ICS-T) is a set of brief rating scales for teachers and parents. It consists of 18 items that assess social and behavioural characteristics of children and youths. The ICS-T yields three primary factors: AGG (argues, trouble at school, fights), POP (popular with boys, popular with girls, lots of friends), and ACA (spelling, math). Subsidiary factors include AFF (smile, friendly), OLY (appearance, sports, wins), and INT (shyness, sad, worry). The psychometric properties of the scale (internal structure, reliability, long-term stability) are presented and evaluated over successive ages. The scale factors have been linked to contemporaneous observations of behavior and social network membership. Developmental validity of the ICS-T includes the significant prediction of later school dropout and teenage parenthood. The ICS-T scale is described, along with instructions for use and scoring.

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The hypothesis that certain heritable personality traits would correlate with increased vulnerability to tumor development and reduced natural killer (NK) cell function was tested in mice selectively bred for high and low levels of aggression. This selection program produces a line of mice that fail to exhibit species typical, isolation-induced aggression, but appear socially inhibited in response to a novel partner mouse. All socially inhibited mice developed 3-methylcholanthrene-induced tumors compared with only 44% of the aggressive mice. Basal NK activity was also significantly lower among socially inhibited mice. Conversely, there were no line differences in NK activity between the aggressive line and nonselected, socially isolated mice, consistent with other unidirectional outcomes of this selective breeding program. No significant line differences were present for nonsocial measures of emotional reactivity (e.g., fearfulness) or serum corticosterone levels. These findings support the hypothesis that social "traits" may be related to immune function and tumor susceptibility.

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The central questions of social development--from the roots of mother-infant attachment to the plasticity of aggressive behavior--pivot on the relations between genetic and ontogenetic sources of variance. It is proposed that (a) developmental, experiential, and microevolutionary processes typically collaborate, rather than compete, in achieving social adaptation; (b) social behavior patterns are mostly closed to modification in the course of development and across generations, but avenues of vulnerability exist in ontogeny and microevolution for dynamic, rapid, and reversible changes in key features; (c) a general avenue for change is delay or acceleration in the developmental onset of one or more features of the behavior pattern, which in turn modifies the functions and properties of the adaptive configuration; and (d) the features of social behavior that are open to rapid change in ontogeny should be open as well to rapid changes in microevolution, although different underlying processes may be involved. Empirical findings from the investigation of aggressive interactions are used to illustrate this proposal on the dual genesis and coincident adaptation of social behaviors.

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Firearm injury is the second leading cause of death among teenagers. In this study we examined firearm acquisition and ownership in a biracial cohort of 664 teenagers (313 male and 351 female). Ownership was prevalent among male adolescents (48%) and rare among female adolescents (4%). Among these suburban and rural teenagers, the ownership rate was highest for white male adolescents (56%). Handgun ownership was more frequent among male school dropouts (22%) than enrollees (7%). The first firearm was typically acquired by late childhood or early adolescence (median age, 12.5 years). An adult male family member (eg, father, grandfather, uncle) was the primary source. The prevalence, developmental timing, and sociodemographic correlates of firearm acquisition should be useful for informing preventive clinical practice and interventions.

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This longitudinal study examined behavioral, cognitive, and demographic factors associated with early school dropout. Follow-up assessments were completed on a sample of girls (n = 248) and boys (n = 227) who had first been seen when they were in the seventh grade. School status was determined for all living subjects; 99% of them were interviewed individually in the fifth annual test wave. Overall, 14% of the group had dropped out of school prior to completing grade 11. The clusters of males and females most vulnerable to early school dropout were characterized in grade 7 by high levels of aggressiveness and low levels of academic performance (82% early dropout in males; 47% early dropout in females). In seventh grade, subjects who subsequently dropped out tended to affiliate with persons who were also at risk for dropout. Socioeconomic status, race, and early parenthood were also associated with school dropout. The primary outcomes were supported by convergent variable-oriented and person-oriented analyses. Some developmental dynamics of the phenomena are discussed.

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This research was designed to investigate development and behavioral mediation in lines of ICR mice that have been selectively bred for aggressive behavior. General behavioral reactivity and behavioral immobility have been implicated as potential mediators by prior analyses of preattack interactions. To evaluate the separate roles of these dispositions, the emergence of attacks in genetically selected lines was tracked for 11 years by three levels of analysis: over successive generations, over development, and over dyadic interactions. Convergent outcomes were observed in all three levels with respect to two findings: (a) Robust line differences were obtained in attack behaviors, and (b) strong associations were found between line differences in attacks and line differences in behavioral immobility. Conversely, all three levels of analysis indicated a weak and inconsistent association between line differences in attacks and measures of social and nonsocial reactivity.

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In order to investigate the proposal that modifications in developmental rate may mediate differences in aggressive behavior, two series of selective breeding studies were completed. Stable lines of mice that differed in the frequency and latency of attacks were rapidly established in two series (by S1 in the first series and S3 or S4 in the second series). For evaluation of the developmental-genetic proposal, an analysis was made of the ontogeny of aggressive expression in male mice of the two series, with a detailed report provided of the S1 and S4 generations of the second breeding series. Comparisons between the results of a longitudinal design and the results of a new type of cross-sectional design (involving only siblings, or co-sibial) indicated (a) a reliable developmental course of attack expression, with a sharp rise in early maturity and a slow decline thereafter; (b) a convergence in later maturity of the behavior of lines selectively bred for high or low aggressive behavior, if the animals had been assigned to the longitudinal design; (c) a strong effect of repeated testing on attack latency and frequency, even though the dyadic tests were brief in duration and separated by long intervals. In addition, cross-generational comparisons suggested that the selective breeding differences came about primarily by changes in the behavior of the low aggressive lines, in that these animals failed to show in early maturity the sharp increases in attack occurrence that were observed in earlier generations. Certain implications of these findings for developmental and evolutionary concepts (e.g., neoteny, acceleration, heterochrony) are discussed.

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