A developmental model of antisocial behavior is outlined. Recent findings are reviewed that concern the etiology and course of antisocial behavior from early childhood through adolescence. Evidence is presented in support of the hypothesis that the route to chronic delinquency is marked by a reliable developmental sequence of experiences. As a first step, ineffective parenting practices are viewed as determinants for childhood conduct disorders. The general model also takes into account the contextual variables that influence the family interaction process. As a second step, the conduct-disordered behaviors lead to academic failure and peer rejection. These dual failures lead, in turn, to increased risk for depressed mood and involvement in a deviant peer group. This third step usually occurs during later childhood and early adolescence. It is assumed that children following this developmental sequence are at high risk for engaging in chronic delinquent behavior. Finally, implications for prevention and intervention are discussed.

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Herbivores in nutrient-limited systems such as arctic tundra have been suggested to play a minor role in controlling plant growth simply because they are relatively few in number. However, theory predicts that as net primary productivity (NPP) increases because of greater inputs of nutrients or energy, herbivores may have greater effects on plant growth. This prediction has not been tested in the context of climate warming in arctic tundra, which may increase soil nutrient availability and thus NPP. We examined a long-term experiment that excluded small and large mammalian herbivores and increased soil nutrients in two arctic Alaskan tundra communities: dry heath (DH) and moist acidic tussock (MAT). In the ninth year of manipulations, we measured weekly growth of three plant species of three growth forms: tussock-forming graminoid, rhizomatous graminoid, and dwarf deciduous shrub, in each community. All species grew better when fertilized. In DH, this increase in growth was exaggerated when plants were protected from herbivores, confirming that herbivory had a negative effect on plant growth under increased nutrient conditions, but was unimportant under ambient soil conditions. However, in MAT, the importance of herbivory differed among species with fertilization. The tussock-forming sedge at MAT, Eriophorum vaginatum , grew better and flowered more when fenced under both ambient and amended nutrients compared to plants exposed to herbivores. This species decreases in abundance in long-term fertilized plots when mammals are present, and our results suggest that herbivory may be accounting for at least some of that loss, in addition to shifts in competitive relationships. Although we only focused on individual plants here rather than the entire community, our results suggest that under the increased soil nutrient conditions expected with continued climate warming in the Arctic, herbivores may become more important in affecting several abundant tundra plant populations, and should not be ignored.

The long-term consequences of antisocial behavior in children are well documented. Yet little is known about the pattern of development and sequence of antisocial behaviors in home and school settings. This article describes the rationale, methodology, and measures of a 5-year longitudinal research study of the development of antisocial behaviors in a high-risk population of boys in school settings. Subjects for this longitudinal study are 80 fifth-grade boys divided into two separate cohorts. These subjects were a subset of a sample of 200 boys included in an extensive study of the role of family variables in the development of antisocial behavior. Results from the first year of the study regarding 35 boys of Cohort I are presented in this paper. Multiple assessment methods were used including direct observations of social interactions in free-play activities and academic engaged time in classroom activities, teacher ratings of social skills, and examination of student records. Results indicated that subjects in the group more at risk for engaging in antisocial behavior were significantly different from subjects in the control group in their amounts of academic engaged time, frequencies of negative interactions with peers in playground situations, frequency of discipline contacts, and in teacher ratings of their social skills. Implications for identifying patterns and sequences of antisocial behavior are discussed