The recent data on violence among youth have drawn the attention of both the public and the scientific community. In 1989, for example, homicide was the second leading cause of death among persons between 15 and 24 years of age. In that same year, close to 5%, or an estimated 4.6 million households nationwide, had a member who had experienced one or more violent crimes (US. Department of Justice, 1991b).Data suggest that the incidence and prevalence of violence differ across social and cultural groups in the United States. In particular, violent crime victimization and perpetration rates have consistently revealed differing patterns of violence associated with each of the dominant ethnic minority groups in the United States (Roper, 1991; see also chapters 4-7 of this book). This is perhaps most clear when considering statistics on violence among youth in these groups. Rather than being the second leading cause of death among 15to 24-year-olds, for example, homicide is the number one cause of death among African American youkh (Fingerhut, Ingram, & Feldman, 1992). And, for US. Latino and Native American youth, data show that victimization rates for crimes of violence are higher than those for White non-Latinos (US. Department of Justice, 1991a). (For additional demographic and epidemiological data on violence involving members of ethnic minority groups, see chapters 4-7 in this book.)Researchers have questioned just what it is about racial and ethnic differences in the United States that seems to be associated with varying rates of violence (D. Hawkins, 1990). One important answer has been found by looking a t risk factors for violence and a t population demographics. The data indicate that social risk factors such as unemployment, high population density, poverty, and drug abuse, among others, are associated with being both victims and perpetrators of violent crimes (Sampson, 1993). At the same time, population demographics indicate that these risk factors are overrepresented among members of ethnic minority groups and may, in part, account for the 59

Psychologists have made major strides over the past 50 years in understanding the multiple etiologies of youth violence. As noted in many of the chapters in this book, violent and aggressive behavior in children and youth is an outgrowth of an array of historic, ecological, cultural, demographic, biological and psychological risk factors, many of which have been studied by psychologists as well as other scientists.In this regard, many of the chapters in this book have noted that violence is not randomly distributed throughout the population. For example, now, as in times past, both perpetrators and victims of violence are concentrated in low-income areas. However, the fact that only a small percentage of the children living in these environments engage in aggressive and violent behaviors emphasizes that there is still much to be learned about why some youth become violent and others do not.A synthesis of the research reviewed in this book demonstrates the multiple and varied processes that can thrust individual children on a developmental pathway or trajectory leading to violence. Although by no means inevitable, too often the trajectory suggested involves the following sequences.Economic and social disorganization in communities promotes family disequilibrium. Weak bonding to caretakers in infancy and ineffective parenting techniques including a lack of supervision, inconsistent discipline, and failure to reinforce positive, prosocial behavior in young children all have been shown to lead to subsequent poor peer relations and high levels of aggressiveness. Extremely aggressive young children tend to be rejected by many of their more conforming peers and perform poorly in school. Later, many of these highly aggressive youngsters have poor school attendance and numerous suspensions. Such peer-rejected children tend to establish relationships with others similar to themselves and enter into deviant peer groups. The more such children are exposed to violence in their homes, communities, and the media, the greater the risk for aggressive and violent behaviors. Although psychologists 435