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Chapter 4:
Risk Factors for Youth Violence

Introduction to Risk and Protective Factors

Risk Factors in Childhood

Risk Factors in Adolescence

Proposed Protective Factors in Childhood and Adolescence



Appendix 4-A: Lipsey and Derzon’s Classes of Risk Factors

Appendix 4-B: Violence in the Media and Its Effect on Youth Violence

Media Violence: Exposure and Content

Major Behavioral Effects of Media Violence

Summary of Major Empirical Research Findings

Preventive Efforts



Appendix 4-B


American children and youths spend, on average, more than 4 hours a day with television, computers, videotaped movies, and video games (Roberts et al., 1999; Woodard, 2000). But their exposure to media varies considerably, depending on their age, parental viewing habits, and family socioeconomic status (SES). Most systematic research on children’s exposure to violent media dates back to the 1970s, when most families did not have access to cable television, music videos, video games, or the Internet. As noted earlier, very few contemporary studies systematically document children’s actual consumption of violent media; this is particularly true for the newer media.

Several content analyses over the last 30 years have systematically examined violence on television (Gerbner et al., 1980; Potter et al., 1995; Signorielli, 1990). The largest and most recent of these was the National Television Violence Survey (NTVS)1 (Wilson et al., 1997, 1998), which examined the amount and content of violence2 on American television for three consecutive years, as well as contextual variables that may make it more likely for aggression and violence to be accepted, learned, and imitated. Smith and Donnerstein (1998) report the following NTVS findings:

  • 61 percent of television programs contain some violence, and only 4 percent of television programs with violent content feature an "antiviolence" theme.
  • 44 percent of the violent interactions on television involve perpetrators who have some attractive qualities worthy of emulation.
  • 43 percent of violent scenes involve humor either directed at the violence or used by characters involved with violence.
  • Nearly 75 percent of violent scenes on television feature no immediate punishment for or condemnation of violence.
  • 40 percent of programs feature "bad" characters who are never or rarely punished for their aggressive actions.

The NTVS report notes that many television programs fail to depict the harmful consequences of violence. Specifically, it finds that of all violent behavioral interactions on television, 58 percent depict no pain, 47 percent depict no harm, and 40 percent depict harm unrealistically. Of all violent scenes on television, 86 percent feature no blood or gore. Only 16 percent of violent programs feature the long-term, realistic consequences of violence.


Because an exhaustive description of the research literature is not possible within this brief discussion, findings from meta-analyses are reported3 where available. In meta-analyses, the results of multiple studies are combined and compared systematically and an overall effect size computed. These analyses include findings from randomized experiments that look at aggression immediately after viewing violence, as well as cross-sectional surveys that provide a snapshot of the relationship between viewing violence and behavior at a fixed point in time. Also presented are findings from longitudinal studies that examine whether exposure to media violence affects violence and aggression over time.

Television and Film Violence

Many anecdotal reports have described instances in which television and film violence led to immediate violent behavior in individual children, but scientific studies of this relationship draw a more complex and qualified picture. Most of the relevant research has focused on how watching dramatic violence on television and film affects aggressive thoughts and emotions, as well as aggressive behavior. Some important studies address violence as well.

Experimental Studies

A substantial number of laboratory and field experiments over the past half-century have examined whether children exposed to violent behavior on film or television behave more aggressively immediately afterwards (see reviews by Bushman & Huesmann, 2000; Comstock & Scharrer, 1999; Geen, 1990; Geen & Thomas, 1986; Huesmann et al., 1997). Many studies have also examined the immediate effect of media violence on aggressive thoughts or emotions (Rule & Ferguson, 1986), which have been shown to increase the risk of aggressive behavior (Dodge & Frame, 1982; Huesmann & Guerra, 1997).

The most recent and comprehensive meta-analysis of media violence was conducted by Paik and Comstock (1994), who examined effect sizes from 217 empirical studies on media violence and aggressive and violent behavior published between 1957 and 1990. The analysis indicates clearly that brief exposure to violent dramatic presentations on television or in films causes short-term increases in the aggressive behavior of youths, including physically aggressive behavior. Across all the randomized experiments, the unweighted average effect size was large (r = .37).4 When only experiments examining physical aggression as the outcome were examined, the effect size was also large (r = .32).

Although the experimental methods used in these studies enable researchers to test causality more readily than other research methods as noted by Comstock and Paik (1991), the findings may not necessarily apply to all real-world settings. Because experiments are narrowly focused on testing specific causal hypotheses, they do not examine the effects of all factors that might be present in more realistic situations. This means that some real-world influences might actually lessen or even eliminate the aggressive reactions observed in experiments. For example, while television, film, and other media contain a variety of antisocial and other messages, most laboratory studies to date have exposed study participants primarily to violent materials. In addition, participants may react differently in the laboratory when they realize that their expressions of aggression will not be punished (Gunter, 1983). Any summary of these experimental results should also acknowledge the argument raised by some critics (such as Freedman, 1992) that many study participants provide the responses they believe the researcher wants. Despite these limitations, laboratory experiments are important because they allow researchers to isolate the unique effect of exposure to violence on subsequent behavior.

An important general finding from these experimental studies is that not all youths seem to be affected equally by media violence. Effects seem to be strongest on youths who are predisposed to be aggressive for some reason or who have been aroused or provoked (Berkowitz, 1993; Bushman, 1995; Geen & O’Neal, 1969).

Cross-Sectional Surveys

Cross-sectional surveys over the past 40 years have generally focused on establishing a link between the current aggressiveness of children and the amount of television and film violence they watch regularly (see reviews by Bushman & Huesmann, 2000; Chaffee, 1972; Comstock & Scharrer, 1999; Eysenck & Nias, 1978; Huesmann & Miller, 1994).

Paik and Comstock’s meta-analysis (1994) indicates that in cross-sectional surveys viewing media violence was positively correlated with various measures of aggression. They reported small to moderate effect sizes across all measures of aggression (r = .19) and for physical aggression alone (r = .20). For the outcome of most concern to this report—criminal violence against a person—the effect size was small (r = .06). These results suggest that the link between media violence and aggressive behavior found in laboratory studies may also hold for behaviors outside the laboratory. However, cross-sectional surveys do not by themselves indicate whether media violence is causing aggression, whether aggressive youths are attracted to media violence, or whether some other factor is predisposing some youths to watch more violence and behave more aggressively.

Longitudinal Studies

Long-term studies in which exposure to media violence in early childhood is related to later aggression and violence (such as aggravated assault, robbery, rape, and homicide) can identify the enduring effects of media violence. In most such studies to date, however, aggression, not violence, has been the primary outcome measured. In the absence of a meta-analysis, the findings of three frequently cited longitudinal studies on the effects of media violence are discussed briefly below. Studies examining effects over shorter time periods (Singer et al., 1984) or with international samples (Huesmann & Eron, 1986) are not included here.

In a study begun in 1960 on a sample of 875 youths in New York State, Eron and colleagues found that for boys, but not for girls, exposure to media violence at age 8 was significantly related to aggressive behavior a decade later (r = .31, N = 211, p < .01) (Eron et al., 1972; Lefkowitz et al., 1977). At both times, peers assessed physical and verbal aggression. The longitudinal correlation remained above .25, even in separate analyses statistically controlling for factors such as the child’s initial aggressiveness, the child’s intelligence, family SES, parents’ aggressiveness, and parents’ punishment and nurturance of the child.

Milavsky et al. (1982) examined the probability of initiating aggression after exposure to violence on television in 2,400 boys and girls age 7 to 12 from two midwestern cities who had been surveyed up to six times between 1970 and 1973. A sample of 800 teenage boys5 was studied at five times to identify the effect of violent television on aggression and violence. For the elementary school sample, the average cross-sectional correlation between exposure to media violence and personal aggression was small for boys (r = .17) and large for girls (r = .30). The researchers then attempted to predict aggressive behavior at one point in time from the extent to which children viewed television violence at an earlier time, while controlling for earlier aggressive characteristics. They examined this prediction over 15 time intervals ranging from 5 months to 3 years apart. For elementary school boys, only 2 of the 15 predictions at different intervals were statistically significant. For girls, only three predictions were statistically significant. In the teenage male sample, only one of eight correlations was significant. In only one of nine analyses using measures of violence (for example, knife fight, car theft, mugging, gang fight) were boys with greater exposure to television violence more likely to initiate violence 2 years later than those with less exposure.

The third longitudinal study of media violence effects began in the late 1970s and spanned five countries (Huesmann et al., submitted; Huesmann et al., 1984; Huesmann & Eron, 1986). In each locale, samples of middle-class youths were examined three times between age 6 to 8 or age 8 to 11. Both physical and verbal aggression were assessed by peers. The correlations between aggression and overall viewing of television violence at a single point in time were small to moderate and often significant. In the United States, the 3-year average correlation was moderate for boys and for girls (r = .25 and r = .29, respectively; p < .001). The predictive power of viewing television violence for childhood aggression a year later varied substantially. In the United States, girls’ viewing of television violence had a significant effect (b = .17, N = 89, p < .05) on their later aggression, even after accounting for early levels of aggression, SES, and scholastic achievement. For boys, television violence alone did not predict later aggression. When the investigators took into account both exposure to television violence and identification with aggressive television characters, they found a positive relation with aggressiveness (b = .19, N = 84, p < .05).

A follow-up study of over 300 people in the U.S. sample 15 years later suggested that media violence has a delayed effect on aggression (Huesmann et al., submitted). There was a small to moderate longitudinal correlation between childhood television viewing and a composite measure of young adult aggression (physical, verbal, and indirect aggression) for both men (r = .21, N = 153, p < .01) and women (r = .19, N = 176, p < .01). When the outcome was limited to physical aggression, the correlations were smaller (r = .17 and r = .15, respectively). Furthermore, women who had watched relatively more television violence as girls committed significantly more specific acts of violence as adults, such as "punching, beating, or choking another adult," than did the other women (17 percent versus 4 percent). There were no significant differences among the men. Other analyses showed that effects remained significant even when researchers controlled for parent education and children’s scholastic achievement (b = .19 for boys, b = .17 for girls, p < .05). In addition, aggressive behavior did not significantly increase boys’ or girls’ viewing of television violence (b = .08 for boys and b = .04 for girls; p = ns).

In summary, these longitudinal studies show a small, but often statistically significant, long-term relationship between viewing television violence in childhood and later aggression, especially in late adolescence and early adulthood. Some evidence suggests that more aggressive children watch more violence, but the evidence is stronger that watching media violence is a precursor of increased aggression.

Other Studies

Other studies have explored the behavioral impact of introducing television in several countries (Centerwall, 1989a, 1989b, 1992; Joy et al., 1986; Williams, 1986). These studies indicate that when television was introduced, aggression and violence increased. The findings must be viewed with caution, however, because they do not take into account a range of other factors that may influence national crime rates and the amount of violence watched on television.

Despite anecdotal reports of a "contagion of violence," relatively little systematic research has examined whether seeing or hearing about violence in news coverage encourages violent or aggressive behavior. On the whole, the limited data available support the notion of a contagion effect. This evidence is derived from studies examining how reports of a well-known person’s suicide affect the likelihood of imitative suicide (Phillips, 1979, 1982; Simon, 1979; Stack, 1989). Other studies of the contagion effect (Berkowitz & Macaulay, 1971; Phillips, 1983) have been questioned because of their research methods and the ambiguity of their results (Baron & Reiss, 1985; see Phillips & Bollen, 1985 for a response). This area merits additional research.

Violence in Other Media


Theoretically, the effects of exposure to media violence extend to Internet media as well. To date, however, no studies have been published regarding the effects of Web-based media violence on youth aggression and violence.

Music Videos

A relatively small amount of research has focused on the impact of music videos with violent or antisocial themes (Baxter et al., 1985; Caplan, 1985; Hansen & Hansen, 1990; Johnson et al., 1995a, 1995b; Rich et al., 1998). Randomized experiments indicate that exposure to violent or antisocial rap videos can increase aggressive thinking, but no research has yet tested how such exposure directly affects physical aggression.

Video Games

The impact of video games containing violence has recently become a focus of research because children are theoretically more susceptible to behavioral influences when they are active participants than when they are observers. To date, violent video games have not been studied as extensively as violent television or movies. The number of studies investigating the impact of such games on youth aggression is small, there have been none on serious violence, and none has been longitudinal.

A recent meta-analysis of these studies found that the overall effect size for both randomized and correlational studies was small for physical aggression (r = .19) and moderate for aggressive thinking (r = .27) (Anderson & Bushman, in press). In separate analyses, the effect sizes for both randomized and cross-sectional studies was small (r = .18 and .19, respectively). The impact of video games on violent behavior remains to be determined.

Potential Moderators of Behavioral Effects

Research suggests that not all youths are affected in the same way by viewing media violence. Factors that appear to influence the effects of media violence on aggressive or violent behavior include characteristics of the viewer (such as age, intelligence, aggressiveness, and whether the child perceives the media as realistic and identifies with aggressive characters) and his or her social environment (for example, parental influences), as well as aspects of media content (including characteristics of perpetrators, degree of realism and justification for violence, and depiction of consequences of violence).

Evidence that these factors moderate the influence of media violence is limited, and it is more relevant to aggression than to violence. For example, studies of responses to violent television and films and violent video games have found that people who were initially more aggressive than other subjects were more affected in behavior, thoughts, and emotions (Anderson & Dill, 2000; Bushman, 1995; Bushman & Geen, 1990; Friedrich & Stein, 1973; Josephson, 1987). Research in this area clearly suggests that the impact of violent television, film, and video games on aggression is moderated by viewers’ aggressive characteristics.

Evidence that other individual, environmental, and content factors moderate the effects of exposure to media violence is less clear. Some studies suggest that these factors may buffer or enhance effects, but few have tested for such influences. Although limited in scope and depth, such studies provide clues to potential avenues for prevention efforts. For example, preliminary data point to the potentially vital role of parents in supervising their children’s exposure to violent media and in helping them interpret it (Nathanson, 1999).



The NTVS randomly sampled programs from 6:00 a.m. to 11:00 p.m. on 23 broadcast and cable channels over a 20-week period from October to June during the 1994 through 1997 viewing seasons. A sum of 119 hours per channel, or 2,500 hours of television programming, was assessed each year.
2The NTVS defined violence as "overt depiction of a credible threat of physical force, or the actual use of such force intended to physically harm an animate being or group of beings." Content analyses of television programs generally treat the program itself as the unit of analysis and exclude advertisements. "Violence also includes certain depictions of physically harmful consequences against an animate being or group that occur as a result of unseen violent means. Thus, there are three primary types of violent depictions: credible threats, behavioral acts, and harmful consequences" (Smith & Donnerstein, 1998, p. 170).
3In the text to follow, all reported results are statistically significant (p < .05).
4In this study, all effects are unweighted average effects.
5These predictions are based on subsamples from which many of the most aggressive children had been dropped by the research team, reportedly because they were not accurately describing their television viewing.

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