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Institute of Medicine (US) and National Research Council (US) Committee on the Science of Adolescence. The Science of Adolescent Risk-Taking: Workshop Report. Washington (DC): National Academies Press (US); 2011.
The Science of Adolescent Risk-Taking: Workshop Report.
Show detailsThe workshop discussions of biobehavioral and psychological perspectives on adolescent risk behavior alluded repeatedly to the importance of the cultural and social contexts in which young people develop. Presenters described research on the ways family, peers, schools, communities, and media and technology influence adolescent behavior and risk-taking.
FAMILY
There are strong reasons to think that families, and their economic circumstances in particular, influence both parents’ and children’s emotions and behaviors, Rand D. Conger explained. He described some of the evidence for these effects, the specific processes involved, and some of the implications for intervention. Nancy A. Gonzales described the relationship between family influences and particular risk behaviors, as well as interventions that have been developed to alter these influences.
Effects of Economic Distress
The social causation model, Conger explained, provides a framework for considering the way in which economic disadvantage and social conditions affect family functioning and the ways that children develop.
Recent studies have provided evidence that economic factors influence families. Costello and colleagues (2003), for example, found that children whose families were lifted out of poverty when a gambling casino opened on an Indian reservation showed improvement in both psychiatric symptoms and conduct problems. Specifically, this study found that externalizing signs, including such behavior disorders as conduct disorder, improved, but that families’ improved economic circumstances did not affect the rate of internalizing psychiatric problems, such as depression. The researchers concluded that the improvements came about in part because of improved parenting practices. Experimental studies, such as the New Hope study (Huston et al., 2003), have also shown that interventions that increased employment and reduced poverty resulted in similar improvements.
Researchers have described three primary models for thinking about how economic factors influence families: the family stress model, the investment model, and the interactionist model. Research on the family stress model goes back to the 1930s, Conger said, and has since been well replicated using many samples from diverse backgrounds. It is based on evidence from both human and animal studies that punishing experiences, such as economic pressure,1 exacerbate negative affect, which can take many forms, such as despondency, depression, anger, or aggression (Berkowitz, 1969). These sorts of emotions can disrupt family relationships. The effect of the hardship depends on the way it affects daily life—in other words, the emotional response of the family and the individual are what determines the psychological effect of the event. When parents become depressed, angry, and sullen with one another and have increased conflict, the result is often harsh and inconsistent parenting or withdrawal. For adolescents, that can mean increases in risky behavior and less development of the sorts of competencies that protect them from those risks. Conger observed that other sorts of distress may also affect families in the same way. That is, when stress and challenge are high for parents, they generally have an increase in emotional and behavioral problems, which in turn affect family functioning and increase risks for children.
The model, which is consistent with findings from numerous studies (Conger et al., 2010;Conger and Conger, 2008; Conger and Donnellan, 2007), is illustrated in Figure 5-1. Some interventions based on this model have focused on improving families’ economic circumstances. However, although the downward spiral can occur very quickly, such interventions work much more slowly. Thus, in Conger’s view, interventions that reduce the harm during the economic transition are also needed. Promising targets include:
- Reducing parental distress,
- Reducing parental conflict and relationship difficulties,
- Promoting effective parenting, and
- Incorporating the children’s perspectives, that is, encouraging them to feel that they are part of the solution to the family’s difficulties.
While these approaches appear to hold promise, Conger identified areas in which further research is needed. For example, not enough is known about potentially lasting effects of hardship experienced by young children and how they might affect adolescent behavior and risk-taking. The role of self-regulatory and personality processes, which can play a protective role, could also be better understood.
Influences and Interventions
Gonzales focused in greater detail on the ways in which families influence adolescent risk behavior and effective interventions. Effective parenting, she explained (nurturing, supportive parenting that includes clear and consistent discipline), can prevent negative behaviors and also promote prosocial behaviors and values. It also helps children develop various competencies that are also protective. Parental monitoring and supervision may prevent children from associating with deviant peers. High levels of family conflict and poor communication skills disrupt parenting and family relations, reduce children’s emotional security, and reinforce the use of aggression and interpersonal hostility. Family members may model risk behaviors and deviance or effective emotional and social skills, and they may also endow their children with genes that predispose them to certain risks (e.g., substance abuse).
Thus, most family interventions are attempts to change one or more of these processes, and a variety of evidence from cross-sectional, longitudinal, and experimental prevention trials has yielded support for several conclusions (NRC and IOM, 2009):
- Parents who form warm relationships with their children and have minimal conflict with them, provide adequate monitoring and supervision, and do not provide models of drug use can protect youth from developing substance use disorders.
- Lack of strong positive relationships with parents increases involvement with deviant peers, which increases adolescents’ risk for a variety of problems, including precocious transitions, such as early pregnancy, premature independence from parents, and school dropout.
- Parental monitoring and positive parental relationships have been linked with later sexual debut, fewer sexual partners, and increased condom use.
Many social risk factors have been shown to increase the likelihood that adolescents will engage in risk behaviors as well as to disrupt parenting and family processes. Thus, parenting and family processes are the most common targets of interventions for families experiencing adversity, such as economic hardship; parental divorce, death, or mental illness; or parental criminal activity.
Research has shown that these core processes work the same way across many racial and ethnic groups; where cultural differences are evident, they reveal differences in the magnitude of the effect. Core family values, expectations, and goals, however, do vary across ethnic groups, and these differences must be taken into account when implementing family interventions, Gonzales said. Different risks as well as protective family resources are common in different groups, and these can also be addressed through culturally tailored interventions. Two examples of such programs are the Strong African-American Families Program2 and the Familias Unidas Program.3 Both have reduced early onset of substance use and sexual intercourse, as well as problem behaviors.
Although the evidence for the effectiveness of interventions that target these processes is strong, the challenge is to identify and reach the families that need them. Gonzales used the ecological transactional framework, shown in Figure 5-2, to illustrate the array of influences that affect adolescents. She explained that the family plays a central role in negotiating these influences and has the potential to help protect the adolescent or the reverse. Families vary, for example, in the extent to which they encourage and support education, monitor and manage peer activities, and so forth. Different neighborhoods present different sets of risks and require different strategies.
Prevention researchers distinguish among universal interventions (delivered to all members of a population), selective interventions (delivered to segments of a population identified as being at high risk for a particular outcome), and indicated interventions (delivered to individuals already showing signs of a particular risk). Some interventions operate across these levels, depending on need and risk. Interventions may also focus on a range of ages. Those that focus on young children tend to have comparatively stronger effects, Gonzales observed, because younger children are more malleable. It is often possible to have broader impact on a range of risks with early intervention. Home visits to new mothers, designed to instill positive parent-child interactions from the beginning, is an early intervention that has shown promise. Effects for this approach include reduced physical abuse, aggression, and harsh parenting, as well as reduced antisocial behavior (a precursor to many problem behaviors) in children. The effects are strongest for families in the greatest adversity. Research to document the long-term effects on adolescent behavior, however, has been limited.
Interventions also target stages of transition across development, each of which may present not only new risks, but also new opportunities for influencing outcomes. That is, a developmental turning point may be a place where a negative trajectory is established or an opportunity for adolescents to develop new skills. Many middle school interventions are designed around this idea, Gonzales noted. This is an important stage, Gonzales said, because it is when many risk behaviors are initiated and adolescents face many new challenges, including puberty and the growing importance of peer groups. The Strengthening Families intervention, for example—a universal intervention that addresses the parenting skills of individuals with children ages 10 to 14—has shown success in reducing conduct problems and affiliation with antisocial peers.4 Another example of an early intervention is the Raising Healthy Children program, an elementary school-based intervention designed to improve family bonding with the school while also building children’s competencies for resisting risk (Catalano et al., 2003).
Intervening later in adolescence is more challenging because negative trajectories are often well established by then. One approach that has had success is multisystemic therapy for youth with serious behavior problems (Henggeler et al., 2002). This is a very intensive individualized intervention that focuses on strengthening parenting and family relations (working with families in their homes) and also on removing youth from deviant peer groups, improving their school and work performance, and developing social networks. Evaluations have shown long-term reductions in rates of criminal offending, recidivism, rearrest, and out-of-home placement.
Looking across the literature, Gonzales concluded that meta-analyses and numerous randomized controlled trials have demonstrated strong empirical support for interventions designed to improve parenting and family functioning. These interventions demonstrate effects on many problem behaviors and produce lasting benefits in many cases for ethnically diverse families. Evidence suggests that interventions that simultaneously address risk across contexts may be necessary, particularly at the later ages and also when implemented with youth in low-income neighborhoods and families. The relatively few economic analyses that have been conducted consistently show that benefits outweigh the costs of these interventions.
Research is needed, in Gonzales’s view, to explore how these interventions can be integrated and sustained on a larger scale and how they can be made accessible to parents who have restrictions on their time and mobility.
PEERS
The influence of peers is similarly complex, as Mitchell J. Prinstein and Kenneth A. Dodge demonstrated.
Influences and Interventions
Prinstein began by explaining that, in general, the research literature on peer influence and the interventions related to it are less mature than those on families. A topic that has received considerable research attention is the strong association between adolescents’ attitudes and behaviors and those of their peers. Two possible explanations for this association have emerged. One possible explanation for adolescents’ tendency to belong to homogeneous peer groups is that they select individuals who are already similar to themselves. The other is that, when an individual socializes with particular people, he or she tends to adopt the behaviors or traits they have. Researchers who have explored this question have largely concluded that in most cases both effects are important (Dishion and Owen, 2002; Hall and Valente, 2007; Kandel, 1978; Popp et al., 2008), Prinstein explained.
Researchers in this area have focused primarily on a few behaviors. Figure 5-3 illustrates the degree of support that exists for the influence of peers on different problem and risk behaviors. He noted that several very important areas have received very little attention, such as weight-related behaviors and damaging behaviors, such as self-cutting.
Furthermore, almost all of the research has focused on the influence of adolescents’ best friends. While the best friendship does seem to be an important influence, emerging evidence indicates that other peers also play an important role. Adolescents are quite likely to emulate the behavior of popular peers. They have a strong investment in social comparison and reflected appraisal and with meeting the demands of those considered the most popular in their peer group. Prinstein noted the important distinction between adolescents who are well liked and those who are identified as popular, the latter signifying those who are at the top of a dominance hierarchy. It is the dominant individuals who seem to be the most influential, particularly with regard to high-risk behaviors. They tend to be both aggressive and more than usually prone to those behaviors. Moreover, it is rare for friendship dyads to occur in isolation; more typically they occur within a friendship network or clique. These social patterns are very difficult to study, he added, because they evolve so rapidly. Even those who do not interact with one another within the peer crowd might feel the need to adopt the attitudes or behaviors of the crowd with which they would like to associate.
The influence of romantic partners has also just begun to receive attention, and Prinstein commented that researchers have not always been careful to distinguish these different sorts of peer relationships. Further research is also needed to illuminate the ways adolescents negotiate these complex relationships—how they decide whom to heed among the many possible sources of influence. A facet of that question is that of nonconformity. Adolescents who choose not to conform to the attitudes and behaviors of their peers are under the illusion that their behavior is therefore free of peer influence. But, in fact, by adopting the opposite behaviors, they are still very much cognizant of and influenced by the social norms of their peer group, although they might not realize that their behavior is being influenced by those perceived norms.
Prinstein mentioned strong theoretical reasons to think that times of transition, such as puberty, school transitions, and certain stages of friendships, appear to be key times when peer influence is strongest. These are times when adolescents tend to be particularly sensitive to peer feedback as a source of understanding of their own identity. Adopting the behaviors of those with whom one would like to be friends is a strategy for seeking the relationship. Few researchers have done empirical work in this area or on the question of how peer influence works. Possibilities include explicit peer pressure and social mimicry, and researchers have also proposed an identity-based theory in which it is adolescents’ own perceptions of the behavior in which their peers engage that is the dominant factor in decisions to adopt that behavior.
Related to that possibility is emerging evidence that aggressive and rejected youth, who already have a range of risk factors, also seem to have a difficult time accurately estimating the behaviors of their peers. Youth who have already engaged in a particular behavior also tend to assume that they are in the majority and that others are engaging in similar risk behaviors.
Another possible mechanism for negative peer influence is a process called deviancy training, in which specific types of interactions within friendship dyads may reinforce talk about deviant behaviors. Such talk is strongly associated with subsequent engagement in that behavior. When neither member of a pair of friends has engaged in deviant behavior, laughter and other support usually follows discussion of normative (non-deviant) behaviors. In pairs of friends who have both engaged in a deviant behavior, however, laughter and other encouragement follows talk of rule-breaking. This tendency for adolescents to positively reinforce talk about deviant acts is a very powerful indicator of their long-term likelihood of engaging in the behavior.
Some researchers have shed light on the question of which young people are most susceptible to peer influence. High levels of social anxiety or low levels of self-esteem tend to make adolescents more likely to adopt the perceived behaviors of their peers, as are those who have been rejected. Poor family relationships make adolescents more likely to attract and affiliate with deviant peers and to adopt their attitudes. This is another area in which further research is needed, Prinstein observed.
Deviant Peer Groups
The primary public policy approach to deviant adolescents in the United States today is to aggregate them with other deviant adolescents, Dodge pointed out. Mental health providers offer group therapy and residential treatment to a significant portion of patients. The public education system is increasingly likely to segregate youth with behavior and other problems through academic tracking, special education, in-school suspension, and alternative schools. Youth who end up in the juvenile justice system are placed in training schools, boot camps, or incarcerated, in each case together with other deviant youth. Although there are some potential benefits to interventions that occur in the context of peer groups, there are also very significant adverse effects.
Peers can be a source of reward, satisfaction, and identity development. Meta-analyses, however, have shown that interventions that are effective with individuals are significantly less so when administered to peer groups, as shown in Table 5-1. Research identified here, on programs that treat delinquency and antisocial behavior, shows that in some cases the effect is not just a decrement in the effect but an adverse effect. If the peer group is composed exclusively of deviant youth, there is even greater decrement, as shown in Figure 5-4.
In a study of high-risk boys who were randomly assigned either to a summer peer group camp or to a control group, researchers showed that boys who were placed in the camp for two summers had significantly worse 30-year outcomes than the control subjects (McCord, 1992). Another study (Dishion and Andrews, 1995) showed similar results: high-risk 11- to 14-year-olds were randomly assigned to peer group intervention, family intervention, or a control. Those in the peer group intervention had the worst outcomes, and it was those who were initially only modestly deviant who had the worst outcomes. Another study, Dodge said, showed that although deviant boys in all-deviant groups got worse, deviant boys in mixed groups improved (Feldman et al., 1983).
Similar effects are evident in naturally occurring contexts, such as schools. The growing practice of using in-school suspension to punish students for infractions is one example. Students typically are placed in a classroom with others who have committed infractions. They are not allowed to associate with other students and are often supervised throughout the day by an inexperienced teacher. One study showed that 6th graders in North Carolina placed in this setting had twice the risk of subsequently being suspended in the next year for drug use, compared with other suspended youth (Vigdor, 2008). Another study, of adolescents incarcerated in Florida, showed that those placed in cells with peers convicted of drug-related crimes had a significantly higher likelihood of subsequently being arrested for a drug-related crime themselves than youth placed in other cells (Bayer et al., 2009). The effects are similar for sex offenses, assault, larceny, and burglary.
A similar effect is evident with school placement and grade retention. Children who attend a 6th grade that is part of a middle school, and thus associate with older peers, are more likely to be suspended, have double the rate of violence, and have worse test scores than their peers who attend 6th grade in an elementary school (Cook et al., 2008). Similarly, youth who are instructed in classrooms in which 20 percent of the students had been retained have significantly higher retention rates.
Researchers have found some evidence that these peer influences are reciprocal (Boxer et al., 2006; Lavallee et al., 2006; Multisite Violence Prevention Project, 2008). That is, for example, children in groups in which the majority are aggressive will become more so, and children in groups in which the majority are not aggressive will become less so. The general tendency is for groups to homogenize, but there are several moderators that may either increase or mitigate adverse effects.
The influence of deviant peers is likely to be greater when they are slightly older and more deviant and when it is likely that the peers will interact outside the intervention setting. Similarly, participants who are in early adolescence and are already moderately deviant but are not yet committed to deviant behavior are the most susceptible to deviant peer influence. However, moderators that minimize deviant peer influence include experienced and well-trained leaders and constant monitoring; use of behavioral approaches, such as positive reward structures; highly structured time; the promotion of a cultural norm of nondeviance; and a short duration.
Dodge closed with several ideas regarding interventions for deviant youth. First, he thinks that ineffective programs, placements, and treatments that aggregate deviant peers should be avoided if possible. These include residential schools, boot camps, midnight basketball, and nonstructured after-school programs. Second, he thinks that effective alternatives include individual therapies (such as functional family therapy, multisystemic therapy, and multidimensional treatment foster care), therapeutic courts, individualized early prevention programs (such as the High/Scope Perry Preschool Project, Fast Track, and Positive Behavior Intervention and Support), and programs that offer structure for a general youth population (such as 4H, Boys and Girls Clubs, Scouts, and religious activities), job corps and individual skills training, and efforts to disperse gangs.
When deviant peers are treated together, a number of measures can minimize the negative peer influence. Dodge recommended not placing the most susceptible youth (slightly delinquent early adolescents) in such settings and not placing youth with older, more deviant peers. The factors mentioned above—structured time, monitoring, and short duration—are also important. Finally, he urged that practitioners, program administrators, and policy makers document such placements and evaluate their impacts. The record should include a description of the placement environment, a description of the individuals treated or included, and rigorously designed evaluation.
SCHOOL
School is typically the largest and most important institution with which young people are involved, and it is a primary context for their development, Stephanie Jones observed. She, Sandra Graham, and Douglas Kirby provided three perspectives on the ways school influences adolescent risk behavior. Jones provided an overview of the many aspects of school that may play a role. Schools have broad structural characteristics that vary (such as the socioeconomic status of the population they serve, their size and the ratio of teachers to students, school and classroom size, and student and teacher mobility). She explained they also have microcontexts (classrooms, hallway interactions, cafeteria, bathrooms) and microsystems or networks (among particular sets of peers or teachers and other staff) that influence the experiences an individual has at school, often profoundly. Each of these settings and networks may have distinct characteristics and varying behavioral norms.
Each of these factors interacts and contributes to the experience an individual has at school, in terms of his or her feelings of connectedness to school, perception of safety and general climate, the quality of the relationships he or she forms, and so forth. Jones suggested that these factors have an effect on risk-taking and also on the development of both problems and competencies. Yet because the character and composition of groups fluctuate rapidly and many of the other features may be in flux in the course of a school year, they are very difficult to research. Some research has been able to establish links between structural characteristics of schools and behavioral outcomes, she observed (Astor et al., 2004a, 2004b).
Less attention has focused on the microcontexts and microsystems, and Jones explained that it has been difficult to disentangle the effects of the characteristics students and adults bring to particular schools from the context of the schools themselves. Large-sample studies using multilevel designs would make it possible to examine the intersection of these various factors more carefully, she said. Some promising factors to examine, she added, include patterns of social organization within schools, student monitoring, and behavior management strategies.
Schools currently use a wide array of strategies to change social and behavioral outcomes for their students, Jones explained. These include efforts to improve teachers’ instructional skills—although few focus on their behavior management skills, improving security and surveillance, counseling, or instructional programs. Other approaches include efforts to improve the overall school climate and policies designed to address social structures and relationships. Few interventions address the character of settings within the school. In general, these school-based interventions appear to be effective at reducing alcohol and drug use, dropout rates, and absence and other conduct problems, although effect sizes vary depending on the age of the students and other factors (see, e.g., Durlak et al., 2010). Overall, effect sizes are modest, however.
Methodological issues have hampered research in this area thus far, Jones said. In order to develop more empirical evidence, large samples of schools and short- and long-term longitudinal data covering elementary and middle school would be needed. At present, the field lacks reliable and valid measures of settings, and theoretical modeling of the school environment has not been firmly established.5
Racial and Ethnic Composition
Noting that there are innumerable ways in which school may influence adolescents’ risk-taking, Graham focused on the role of racial and ethnic diversity as a contextual influence on psychosocial risk. This is an important topic, she noted, in part because the demographic composition of the K-12 population has changed and is continuing to change so rapidly, as shown in Table 5-2. Despite these changes, Graham said, the public schools are more racially segregated now than they have been in the last 40 years. The typical white student today attends a school that is 80 percent white, while the typical African-American or Hispanic student attends a school in which two-thirds or more of the students are of their own ethnicity, as illustrated in Figure 5-5. The inner-city schools represented in the figure tended to be in areas of highly concentrated poverty and to have few resources compared with other schools. At the same tine, Graham noted, the Supreme Court’s decision in the 2000 Meredith v. Jefferson County Board of Education case indicated that it did not recognize diversity as a compelling interest for K-12 schools (as it has for postsecondary institutions). Thus, she said, it is important that developmental psychologists be prepared to make the case for why racial and ethnic diversity are important advantages for school communities.
Graham identified four specific ways in which a school’s racial and ethnic composition may influence adolescents’ psychosocial development, using data from a longitudinal study of middle and high school students’ psychosocial adjustment (the Peer Relations Project6). These four ways are peer victimization, school transition, discrimination, and the achievement gap. The first, peer victimization, involves cases in which there is an imbalance of power among young people and the minority group is subjected to psychological, verbal, or physical abuse, such as hitting, name calling, racial slurs, and social exclusion. National surveys indicate that 70 percent of middle and high school students report that they have been bullied at some point (20 to 40 percent within the current school year). In any given classroom, Graham explained, 5 to 15 percent of students are likely to be chronic victims, and 5 to 10 percent are likely to be chronic bullies. Young people ages 8 to 15 report that they are more concerned about emotional maltreatment and social cruelty than they are about anything else, including their academic achievement. It is in part for these reasons that the American Medical Association has designated peer victimization as a public health concern, Graham explained.7
As part of the Peer Relations Project, researchers investigated the hypothesis that peer victimization may be reduced in schools that are racially and ethnically diverse, because there is more likely to be a balance of power among groups in those circumstances, by working with schools in the Los Angeles Unified School District. They classified the diversity of 99 classrooms in 11 middle schools using the Simpson Index (a tool used by sociologists, demographers, and ethologists to measure the relative representation of different groups). The results indicated that students do indeed feel less vulnerable in diverse schools, Graham explained. More specifically, the researchers found that as diversity increased, all students (not just members of minority groups) were less likely to feel victimized, perceived their school as safer, felt less lonely, and had greater self-esteem. In Graham’s view, the results suggest that diversity may buffer some of the normative challenges of early adolescence.
Second, the transition from middle to high school is a time of particular challenge for adolescents, especially if the racial composition of the new school context differs from their previous one. This transition generally involves moving to a larger school and negotiating new relationships with teachers and peers. Adolescents tend to feel more anxious and lonely while they are making this transition, and their academic achievement tends to decline. Here again, the Peer Relations Project researchers examined whether school diversity affects this experience. Looking at Los Angeles schools, they examined the experiences of students who moved to high schools that were either significantly more or less diverse than their middle schools. They found that students transitioning to a school in which their own group was less well represented felt less of a sense of belonging. Even in schools that were diverse overall, the presence of a critical mass of peers of a student’s own ethnicity made adjustment easier.
The third way a school’s racial and ethnic composition may influence adolescents’ psychosocial development is through overt racial and ethnic discrimination. Discrimination has a detrimental effect on adolescents’ mental health and academic motivation and probably their achievement as well, Graham pointed out. She reported empirical evidence that discrimination increases during the first 2 years of high school, is more commonly experienced by boys than girls, and is more common in diverse schools than in nondiverse schools (but experienced by groups not well represented in the diverse schools). At the same time, however, ethnic diversity among the teachers in a school may buffer the effects of discrimination.
Finally, Graham and her colleagues point out that the racial and ethnic composition of a school may have psychosocial effects on the students who then may underperform or disengage from school. They examined whether there are psychosocial factors related to worldviews about race and ethnicity that could help to explain the persistent achievement gap between African-American and Hispanic students and their peers evident on the National Assessment of Educational Progress and other measures. After examining a variety of attitudes and perceptions that could affect academic achievement, they found that a subset of students (approximately 10 percent) have very negative worldviews that may be significant. They think the school rules are unfair, that the discipline is harsh, and that the racial climate is negative. They do not trust the authority figures in school, and they experience racial discrimination. The researchers concluded both that these worldviews are partly shaped by the ethnic composition of schools and that they seem likely to influence academic motivation and achievement.
It is clear, in Graham’s view, that the study of school diversity can improve understanding of the role that racial and ethnic disparities play in both psychosocial and academic outcomes. She advocates reframing the question to ask how, rather than whether, school diversity promotes healthy development and researching both the benefits and the challenges of diversity.
Sexual Behavior and Schools
Kirby focused on the ways in which school experiences affect adolescents’ sexual behavior, drawing on analysis of the research regarding risk and protective factors and the effectiveness of various interventions (Kirby, 2008, 2007; Kirby et al., 2005). First, he noted, although schools seem to be a primary avenue for reaching adolescents, few general school characteristics appear to have much relation to sexual behavior, when other factors are controlled. One reason is that a variety of factors tend to cluster together, so when some are controlled, effects for others will not be evident. For example, a school with a percentage of students receiving free or reduced-price lunch is likely to have students who engage in more sexual risk-taking than other students, but when the poverty level of the family or the community is controlled, the relationship disappears. The one school factor that did emerge as significant, he noted, was connectedness to school. Young people who feel connected to their schools initiate sex at a later age, and those who are also performing well academically also have fewer sexual partners, are more likely to use safe sex practices, and are less likely to get pregnant.
Many studies have also explored the effectiveness of various interventions, and Kirby focused on those designed to provide education about avoiding pregnancy, sexually transmitted diseases, and HIV. He noted that although millions of dollars have been spent on such programs over the past few decades and teen pregnancy rates have declined, it is still the case that 30 percent of all girls become pregnant before they turn 20 and 38 percent of 14- to 19-year-old girls who have had sex have a sexually transmitted disease. Kirby examined experimental or quasi-experimental studies of curriculum-based programs for middle and high school youth and found 48 that met certain criteria for design and other features (described in Kirby, 2008). The studies included both programs that emphasize abstinence and programs that do that and also encourage the use of condoms and contraception. Overall, the results (shown in Table 5-3) indicate that such programs do not actually encourage sexual behavior but may in fact result in youth delaying sexual initiation. He noted modest evidence that abstinence-only programs may have limited beneficial effect, as well as evidence that programs designed to encourage condom use and avoid other risks can be successful. More than two-thirds of the programs had a positive effect on one or more of the risk behaviors, which Kirby characterized as remarkable success.
Kirby concluded that the mixed message of promoting both abstinence and safe sex practices is not confusing to young people and that the programs can be effective with multiple groups: males, females, all major racial and ethnic groups, those who have had sex, those who have not, and youth in both advantaged and disadvantaged communities. The studies indicate that these programs can be replicated (with faithful implementation) and point to program characteristics that appear to be effective. In general, Kirby explained, the most effective programs addressed numerous risk and protective factors that affect sexual behavior. Successful programs that focused on abstinence tended to cover:
- knowledge of pregnancy (biological),
- perception of risk,
- values,
- perception of peer norms about sex,
- self-efficacy to refuse sex,
- intentions to engage in sexual behavior, and
- communication with parents or others.
Programs that focus on encouraging condom or contraceptive use incorporate many of the same features but also include knowledge and attitudes related to condoms and contraceptives. Successful strategies include assigning students to talk with their parents about specific topics. Strategies that do not work include promoting values without talking directly about sex, not giving a clear message about behavior, focusing primarily on technical knowledge, and targeting the curriculum to students who are very impulsive and are high sensation-seekers.
Kirby closed with the observation that this sort of education is not a complete solution. It reduces risk by one-third—a success rate he considers significant, in the context of the many, many influences pushing in the other direction. Ways to bring about even more substantial changes are not yet evident.
COMMUNITY
The communities in which young people live can also have important influences on their development, for good or ill, as both Tama Leventhal and Deborah Gorman-Smith discussed. Both noted that the words “community” and “neighborhood” can be used interchangeably in the discussions of influence and that the definition is not a very precise one. The neighborhood is an important context, Leventhal explained, because it is the place where a wide array of peer and other social interactions take place and where adolescents have access to institutional resources. The structural characteristics of a neighborhood, including its economic status, housing quality, and the availability of resources, are important, Gorman-Smith said. So, too, are the social processes that occur in the neighborhood context, as well as the interactions between community characteristics and other influences, such as peers, family, and schools. Researchers tend to use census units (either the neighborhood, approximately 3,000 to 8,000 people, or the block, from 500 to 3,000 people), although, Leventhal noted, many do not define the term when they survey people about their neighborhoods.
Gorman-Smith noted that much of the research on neighborhood effects has focused not on individual development, but on the neighborhood characteristics that are associated with crime or other negative phenomena. Leventhal described some of the nonexperimental research on links between the sociodemographic character of the neighborhoods where young people live and their engagement in risk behaviors, which is of two sorts. First are post hoc studies, in which existing data sets (usually census data), which provide demographic information, such as racial and ethnic composition and residential instability for a particular point in time, are linked with more detailed information about particular families or individuals who lived in the neighborhood at the time for which data are available. Alternatively, a priori studies are designed to collect data that sample a wide range of neighborhoods or certain types of neighborhoods. In Leventhal’s view, this approach is a more reliable method of estimating neighborhood effects, in part because it makes possible multilevel and longitudinal analyses. One example is the Project on Human Development in Chicago Neighborhoods,8 which combined data on children and families with community survey data, interviews with residents, and observations.
Looking across these sorts of studies, Leventhal noted that even with controls for child and family background characteristics and other factors, there is significant evidence for a connection between socioeconomic status and risk behavior. Living in an affluent neighborhood where the residents are college-educated professionals is associated with advantages for adolescents’ academic achievement, although more so for adolescent boys than for girls. Living in a neighborhood with low socioeconomic status confers risks to adolescents in terms of a host of behavioral, social, and emotional problems. Living in a poor neighborhood also places adolescents at risk for early childbearing and related sexual risk behaviors. In short, there is something about living in a poor neighborhood that places adolescents at risk for engaging in a wide range of risk behaviors.
Leventhal cautioned that because neighborhood residence is not random, the same characteristics may lead families to particular neighborhoods as well as predispose their children to particular outcomes. Moreover, she stressed that neighborhood influences are modest compared with the influence of parent income, parent education, and other family influences.
Researchers have also employed experimental designs to try to address the selection problems with nonexperimental studies. Studies of residential mobility, Leventhal explained, provide the opportunity to observe outcomes for families who are randomly assigned either to receive support in moving to a lower poverty neighborhood or not, although they do not specifically target adolescent risk behaviors. One example is the Gautreaux program,9 an effort to desegregate Chicago’s public housing that began in 1976. Initial studies of the program’s effect (after 10 years) showed that young people who moved to the suburbs were more likely than those who stayed in the poor, urban neighborhoods to graduate from high school, attend college, and be employed and had higher wages. Yet studies of longer term effects were more mixed, showing, for example, that although boys who moved out were less likely to be arrested or convicted for drug offenses than those who stayed, girls who moved were more likely to be convicted of criminal offenses than their peers who stayed.
Another example is the Moving to Opportunity program,10 in which 4,000 families were randomly assigned either to receive a housing voucher that would support them in moving to private housing in a low-poverty urban (not suburban, as in the Gautreaux program) neighborhood or not (there was also a third group that received somewhat different benefits). This study also showed somewhat mixed results, with significantly more positive effects for girls than for boys, as well as a number of areas in which there were no effects, positive or negative (delinquency, sexual behaviors, achievement, and physical health).
Leventhal explored the theoretical frameworks that might explain the influence of neighborhoods. First, she suggested, it is likely that neighborhood structure could have both direct and indirect effects on adolescent risk behavior, but it is also likely that there are specific intermediary mechanisms, such as social processes. Thus, one model for linking neighborhood structure to adolescent outcomes is the institutional resources model, or the hypothesis that young people are influenced by the quality, quantity, diversity, and affordability of neighborhood resources (e.g., schools, health and social services, recreational and social programs, employment opportunities). A second model posits that the “norms and collective efficacy” characteristic of a neighborhood are the primary source of influence. That is, a neighborhood’s collective capacity to work together for common goals and to reinforce prosocial (that is, positive behavior that demonstrates concern for others and constructive goals) norms and values can reduce threats to residents, such as violence and the availability of illicit substances. The third model focuses on the relationships and ties in the neighborhood and highlights the role of families. This model suggests that neighborhood disadvantage contributes to family stress and economic hardship, which, in turn, can have negative consequences on parental well-being, parenting, and adolescent outcomes.
Gorman-Smith also touched on theoretical issues, identifying four similar mechanisms through which community influences young people: social connection and support, social norms, informal social control, and routine activities. She noted that although there is reason to think that the social organization of a neighborhood is important, the census-level data are not an ideal tool for investigating this complex construct. She showed data from several small studies of neighborhood social organizations showing that concentrated disadvantage and the social organization of neighborhoods are only mildly correlated (Gorman-Smith and Reardon, 2008). That is, neighborhoods with comparable poverty levels had very different levels of social organization, and those with less poverty did not necessarily have better social organization than those with more poverty. The important question not easily answered, she suggested, is how some neighborhoods develop social supports and others do not.
Like Leventhal, Gorman-Smith has found that living in a disadvantaged neighborhood may be associated with many poor outcomes for youth, including delinquency, violence, substance use, lower academic achievement, problems with social competence, and mental health problems. The association with violence may be the most studied of these links, she suggested, but the research has not clearly illuminated the reasons why some young people are affected so much more seriously than others. Although some data suggest that different aspects of neighborhoods have independent effects, it seems likely that the effects interact, a situation that presents a difficult research challenge.
Emerging research suggests a role for social and recreational resources in the link between low socioeconomic neighborhood status and adolescent risk behaviors. Leventhal explained, however, that the evidence for the relationship-and-ties model is much more mixed. The most compelling evidence currently available is for the social norms and collective efficacy model. These factors seem to play a strong role in the link between neighborhood poverty and adolescent delinquency and sexual risk behavior. The strength of that evidence, she suggested, highlights the value of community-level supervision and monitoring of youth.
Gorman-Smith also discussed interventions, noting that there have been three primary approaches to keeping communities intact (as opposed to changing their demographic composition). One is to work with individuals and families to manage or cope with the stresses of living in a disadvantaged neighborhood. An example is the SAFE Children program (Schools and Family Education) (Gorman-Smith et al., 2007), which provides families whose children go to school together with support in building networks of social support.11 Another approach is to develop community coalitions or partnerships to address specific social problems in a neighborhood. A third approach is to focus on economic development to improve neighborhood conditions, for example, through business development. Although research on neighborhood effects on adolescent development has produced mixed results, it may be due to the limited nature of this research to date. Most of the research has focused on census data to define disadvantage and poverty, but this may be too limiting a conceptualization of neighborhood. More attention to factors other than information found in census data may be necessary to more fully understand how neighborhood context may influence adolescent development. These data may include information about crime, community businesses and organizations, social factors such as perceptions of fear, or adult monitoring. In addition, Leventhal noted, it may be necessary to examine mediating factors that may help explain neighborhood effects and moderating effects that neighborhoods may have to either exacerbate the negative effects of other risks or enhance the positive effects of adolescent assets and resources. Most of the research to date has focused on the direct or main effects of neighborhoods.
MEDIA AND TECHNOLOGY
Among the environmental influences that affect teenagers’ development, perhaps the most difficult to study is the wide, fast-evolving array of media and technologies that are part of their lives. Any list of the sorts of devices and programming to which young people may have access is likely to be at least somewhat outdated within months, but researchers have begun actively exploring both the effects of media on adolescent behavior and ways of structuring both their interactions with it and interventions designed to address media-related problems, as Michael Rich, Jane D. Brown, and Blair Johnson explained.
Rich began with the point that media—that is, modes of electronic communication and entertainment—are portable, ubiquitous, and integrated into virtually all aspects of adolescents’ lives. He presented some data on media use and its effects, cautioning that the field has not been well funded and that much of the data are cross-sectional and based on self-reports. He focused on data from the Center on Media and Child Health related to the links between media consumption and adolescent sexuality.12
First, he described current patterns of use. On average, 8- to 18-year-olds use media actively for 6 hours and 21 minutes of every day, often using multiple media at the same time (Roberts et al., 2005). Because nearly a quarter of teenagers use two or more media at the same time, they may be cumulatively exposed to more than 8.5 hours of content per day. Researchers have been able to determine little about teenagers’ fore-ground and background attention to this media use or other specific questions about its impact, but there is some information about its content. During the 2001–2002 television season, 71 percent of programs included sexual content, with an average of 6.1 such scenes per hour. Among programs directed at teenagers, 82 percent included sexual talk and two-thirds included sexual behavior (4 percent portrayed sexual intercourse) (Farrar et al., 2003). In a survey, 75 percent of college students reported that they were first exposed to sex in the media when they were minors, and 15 percent had persistent imagery and thoughts related to that exposure. In 1996, more than two-thirds of movies released that year portrayed sexual behavior, and Rich indicated that the percentage has increased each year since (Cantor et al., 2003).
Internet access, now widely promoted even for very young children through toy-related game websites designed as part of product promotion campaigns and the like, has introduced a new source of influence with complex implications. In 2007, there were 44 million Internet users under the age of 18, and 47 percent of 8- to 18-year-olds went online every day (Roberts et al., 2005). Average use was 1 hour per day, although some reported being online as long as 10 to 14 hours per day. And 42 percent had clicked on pornographic sites; 4 percent had been asked for sexual pictures of themselves by someone they did not know (Wolak et al., 2007). Rich cautioned that all of these figures have probably grown since 2007. Usage of social networking sites has also grown exponentially, and Rich noted that recent data suggest that 90,000 of the 110 million users of MySpace are registered sex offenders (“90,000 Sex Offenders Axed in MySpace Clean-Up,” 2010).
While sexual predation by adults is actually quite rare, other kinds of influence may also cause concern. Rich described weblogs created by teens who have chosen anorexia nervosa and bulimia as a lifestyle and post tips for others who would like to adopt it to live life as an extremely thin person. Social isolation related to social networking usage, cyber bullying, and sexting (sending sexual images or text via cell phone) are all new problems for adults to understand and address. Text and images transmitted electronically may in some cases be impossible to expunge, and because the legal code related to the Internet is in its infancy, young people may face serious lasting consequences from a single impulsive act. A total of 70 percent of adolescents have been exposed to pornography on the Internet, and two-thirds of college students report that they consider doing so acceptable (Rideout et al., 2005).
What are the effects of this exposure? A number of studies, Rich indicated, have shown that the more sexual content young people have seen on television, the more likely they are to initiate sexual activity (Collins et al., 2004). As one example, in one study, 12- to 14-year-olds exposed to sexuality in television, movies, music, and magazines were more than twice as likely than those not exposed to have sex by age 16 (Brown et al., 2006). Another study showed that 6- to 8-year-olds who watched adult programming were significantly more likely than those who did not to engage in sex by ages 12 to 14 (Delgado et al., 2009). Another showed that youth whose parents limited television to less than 2 hours per day had half the rate of sexual initiation as those whose parents spoke to their children about not having sex but did not limit their viewing (Ashby et al., 2006).
Theoretical Perspectives
Researchers with several theoretical perspectives have examined possible links between media exposure and changes in sexual attitudes and behaviors, Rich observed. Social learning theory, which has also been applied in the study of media violence, suggests that when individuals see a behavior portrayed in a positive way, they have a tendency to imitate and adopt it. Cultivation theory suggests a slightly different explanation, that what individuals see on television supersedes their own perceptions of the real world around them. Thus, if the social norm on television is extremely prevalent sexuality, individuals who watch the programming begin to think that it is the social norm and believe sexuality is more prevalent than it actually is. A third theoretical model posits that adolescents use media as part of their individuation process. They use their preferences for programming or music to convey messages about their social identity, in the same way that their choices of clothing and peer groups do.
Rich sees media use as so pervasive as to be both a public health and environmental health issue. “It is like the air they breathe, the water they drink, the food they eat. They are neutral. They are not malignant. They are not bad. But they are very powerful. They can be used to do great good or, used thoughtlessly, they can harm,” he suggested.
Johnson focused on the value of applying contemporary persuasion theory to the use of media strategies to influence adolescent behavior. He acknowledged that researchers have not fully explored this approach, so his discussion was largely theoretical. Researchers have posited at least five different current persuasion theories, he explained, although they converge on several significant points.13 One is that there is a trade-off between what he called effortful and noneffortful thinking. That is, when the recipient of a message is highly motivated to expend effort processing it and is well able to grasp the content, there is the potential for the information to alter attitudes, and the content of the message makes a significant difference in the outcome. However, for a recipient whose motivation and ability are low and who is thinking in a relatively shallow fashion, it is the incidental features in which the message is enveloped that may matter more. Thus, for example, marketers tend to rely heavily on peripheral cues that require very little attention to process in developing advertisements. These advertisements succeed because they are repeated over and over, so the message can be imprinted without any effort on the part of the recipient. Johnson pointed out that children and adolescents are most likely to process in a shallow way and to be receptive to peripheral cues, such as strategies that invoke emotional responses.
Several other factors are likely to affect the way individuals process information, and these change in the course of development. Strong attitudes or habits (likely to become more entrenched with age), skepticism (which increases with education), and links to peer groups whose attitudes and behavior may be in opposition to a message all tend to make individuals more resistant to messages that seem discrepant in some way. Thus, Johnson explained, it would be logical to expect that media effects would vary with developmental stage. For preadolescent children, emotional and other nonverbal cues are likely to be most powerful. At that stage, children behave more impulsively than they do later, and the influence of both peers and family are strong. They are open-minded and not terribly skeptical. By early adolescence, the power of emotional cues decreases somewhat, and peer influence becomes stronger. At this stage, young people may be more responsive to content-rich messages. Late adolescents begin to resemble adults in their processing. While still responsive to emotional and nonverbal cues (as all adults can be), young people at this stage have strong attitudes and are capable of defending them. Johnson, however, cautioned that this hypothesis has not been clearly verified with empirical research.
Researchers have demonstrated the influence that media can have on adolescent health, Johnson said. The results of a meta-analysis of health promotion interventions done through 2003 demonstrated a number of significant effects on changes, as shown in Table 5-4 (Johnson et al., 2010).
Johnson added, however, that the meta-analysis also showed that effect sizes for health promotion efforts (looking not just at media campaigns) are generally much smaller for children and youth than for adults, as Figure 5-6 shows (Johnson et al., 2010). He concluded that many factors influence the outcomes. When adolescents are given intensive skills training and supplied with the resources to change their behavior (e.g., given condoms), effect sizes were significantly greater than when they were just the targets of an education campaign. Looking more broadly, he reinforced the theme present in many of the workshop discussions that family, community, peer, and other influences all affect the way adolescents process and respond to public health interventions and messages. At the same time, negative media influences are very powerful— Johnson pointed out that tobacco companies have $20 to use in marketing their product for every $1 states have to use on prevention efforts. Nevertheless, as a 1998 Florida antismoking campaign demonstrated, media campaigns can be effective (Sly et al., 2001). Evaluation of the “Truth Campaign” indicated that it reduced the number of smokers in the state by 29,000, was shown to prevent adolescents from smoking debut, and may have affected young people who do take up smoking by making them more conscious of how often and how much they smoke (CDC, 1999; Sly et al., 2001).
Interventions
Brown picked up on the potential for media to be used as a positive force in young people’s lives, focusing on three media-based strategies.14 Perhaps the most familiar to many people is the use of social marketing approaches for media campaigns. Borrowing some of the expert advertising strategies from the world of commerce, public health experts have targeted large audiences with specific messages, presented in the media used by those audiences. Such messages are usually designed to achieve clear goals, such as increasing knowledge or changing specific attitudes or behaviors. However, Brown explained, social marketers typically do not have the resources to sustain these messages for long periods or repeat them, in the way that commercial marketers can—that saturation coverage may be an important component in the success of commercial marketing. Meta-analysis of the effectiveness of social marketing campaigns has shown that, on average, 4 to 8 percent of those exposed to a social marketing campaign change their behavior (Derzon and Lipsey, 2002; Snyder and Hamilton, 2002). This may sound small, she acknowledged, but media campaigns can reach many more young people than a school- or community-based program could.
Brown also noted that media campaigns are good at raising awareness of problems but more successful at changing behavior when combined with other measures. She likened them to air support for a military ground campaign. In Montana, for example, a program saturated the media with a message about the harmful effects of methamphetamine use at the same time that law enforcement efforts targeted the problem; the effect was a significant decline in use. More generally, in Brown’s view, media campaigns are most successful when they:
- are guided by theory, such as a model of health behavior or social learning.
- target a clearly defined, engaged audience.
- are presented through multiple channels (or saturate a single, well-chosen channel).
- stimulate the target audience to communicate about the issue.
- are sustained over time.
- are presented in an environment that supports the desired outcome in other ways (e.g., including water or lower fat snacks in vending machines at school at the same time a media campaign to promote their use is launched).
Brown described a television campaign developed by researchers at the University of Kentucky that promoted safer sexual practices. Based on a model of the targeted behaviors (which indicated that they should target older adolescents who were highly sensation-seeking and prone to impulsive decision making), the program consisted of public service announcements that saturated particular channels over 21 months. The advertisements were designed using fast cuts and loud music to appeal to the target audience. Data about adolescents’ condom use were collected in the target city and a control city in which there were no such advertisements, and the researchers estimated that there was a 13 percent increase in the practice of safe sex in the targeted city (Zimmerman et al., 2007).
Researchers have also begun to use new media to reach adolescents, although this approach has been less thoroughly studied. Examples include providing public health messages or answers to individual adolescents’ questions via text messaging, interactive CD-ROMs, and DVDs providing information about sexually transmitted diseases, HIV prevention, and the like, which are available in pediatricians’ offices, schools, and websites designed as peer communities that can provide information.
Most media campaigns are expensive, Brown noted, and researchers have not perfected the art of devising effective messages. It can also be difficult to evaluate the effectiveness of such campaigns, particularly when they are conducted on a national level, where so many competing influences may affect young people’s thinking and behavior. She also acknowledged that the results can be unpredictable and that a campaign could have undesirable unanticipated consequences, such as introducing some young people to a behavior they had not previously considered.
A second approach is to embed public health messages in entertainment programming, which, Brown explained, may produce less resistance in target audiences. An example is a collaboration between the National Campaign to Prevent Teen and Unplanned Pregnancy and the magazine Seventeen, to develop an article called “Why Are So Many Girls Still Getting Pregnant?” (Kuster, 2008). The article included interviews with girls about their views and information about ways to avoid pregnancy. Celebrities whom adolescents view as what Brown called “super-peers” can also play a useful role. Adolescents tend to admire and want to imitate role models they see in the media, so involving a rap star, for example, in a public service campaign can make the message much more palatable to the young people who admire him or her. Challenges to this approach include identifying sympathetic media producers willing to produce such messages, the difficulty of controlling messages once a celebrity takes on the role, and sustaining the message over time. Moreover, as with media campaigns, Brown explained, it is very difficult to evaluate the effectiveness of these messages.
Promoting media literacy is the third strategy Brown identified for helping adolescents understand public health topics.15 It can be very valuable to educate adolescents to be more critical users of media, for example, by asking them to keep journals about their reactions to what they see or to engage them in discussion of spoof advertising designed to help them discern hidden messages, in her view. When adolescents can deconstruct the content in what they see, it is easier for them to analyze and adjust their own media diet. They may also be encouraged to create their own media and to respond actively to what they see. Brown pointed out that there has been little evaluation of this sort of education, and schools and educators have been somewhat reluctant to take it on. Schools have not been encouraged to view media literacy as an important educational goal, nor have teachers been trained to address this topic.16
SUMMARY
The experience of adolescence is complicated by a variety of influences that can have both positive and negative effects. A range of research has shown that economic hardship is associated with dysfunctional families and with a range of difficulties for adolescents, including risk-taking. This sort of stress is likely to have a negative effect on parenting, yet positive parenting can also profoundly affect outcomes for young people. Adolescents also tend both to seek out peers like themselves and to become more like the peers with whom they associate—and here, too, the net effect may be positive or negative, although the precise mechanisms of these fluid relationships have not been systematically traced.
Similarly, strong bonds with teachers and peers at school can be a positive influence, but many characteristics of middle and high school are not conducive to the development of such bonds. Communities also may have structural characteristics that are supportive of positive adolescent development—such as social networks and resources for young people—but research has not yet answered specific questions about how schools and communities can develop more favorable structures and cultures. Finally, the rapidly expanding universe of media devices and venues is having a profound influence on the experience of adolescence, with effects that include evolving norms for many behaviors—and particularly a loosening of sexual attitudes and an increase in sexual activity. At the same time, the media provide a potentially powerful tool for influencing young people in a positive direction.
Interventions that address these influences may target broad populations or specific families and individuals who have shown signs of distress. Many focus on key transition points; like the presenters on specific risk behaviors, the presenters on external influences also stressed the value of targeting the youngest adolescents before problems become more firmly established.
Footnotes
- 1
Conger noted that family income is not a reliable measure of hardship because even families with high incomes may face severe economic challenges, for example, if a medical calamity occurs in a family with inadequate health insurance. Thus, researchers consider other factors, such as negative financial events, sudden economic demands, or sudden changes in income.
- 2
- 3
- 4
- 5
The Add Health Study housed at the University of North Carolina collects longitudinal data on the school experiences of teenagers and their later outcomes (http://www
.cpc.unc.edu /projects/addhealth/data [September 2010]. - 6
- 7
For more information on peer victimization, see http://www
.findyouthinfo .gov/topic_bullying.shtml (accessed September 2010). - 8
- 9
- 10
- 11
See http://casat
.unr.edu/bestpractices/view .php?program=107#desc (accessed September 2010). - 12
See http://cmch
.typepad.com/ (accessed May 2010). - 13
Models include the information processing model (McGuire, 1968), the heuristic systematic model (Chaiken, 1980), the unimodel (Kruglanski and Thompson, 1999), the cognition in persuasion model (Albarracín, 2002), and the elaboration likelihood model (Petty and Cacioppo, 1986).
- 14
Much of Brown’s presentation was based on reports from the National Campaign to Prevent Teen and Unplanned Pregnancy (Brown, 2008).
- 15
Brown identified two sources for more information about media literacy: the American Coalition for Media Education (www
.acmecoalition.org) and the National Association for Media Literacy Education (www .amlainfo.org [accessed May 2010]). - 16
The Centers for Disease Control and Prevention offers health standards for youth, which include indicators for media literacy; see http://www
.cdc.gov/healthyyouth /sher/standards/ (accessed September 2010).
- The Influence of Environment - The Science of Adolescent Risk-Taking: Workshop R...The Influence of Environment - The Science of Adolescent Risk-Taking: Workshop Report
- Chain A, CAI-1 AUTOINDUCER SYNTHASEChain A, CAI-1 AUTOINDUCER SYNTHASEgi|254574741|pdb|2WK8|AProtein
- LINC02114 long intergenic non-protein coding RNA 2114 [Homo sapiens]LINC02114 long intergenic non-protein coding RNA 2114 [Homo sapiens]Gene ID:101929153Gene
- lms [Megachile rotundata]lms [Megachile rotundata]Gene ID:100875048Gene
- Gm4221 predicted gene 4221 [Mus musculus]Gm4221 predicted gene 4221 [Mus musculus]Gene ID:100043089Gene
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