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Impact of the Media on Adolescent Sexual Attitudes and Behaviors
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     Center for Health Promotion and Prevention Research, University of Texas Health Science Center, Houston, Texas

    Medical Institute for Sexual Health, Austin, Texas

    ABSTRACT

    Background. Adolescents in the United States are engaging in sexual activity at early ages and with multiple partners. The mass media have been shown to affect a broad range of adolescent health-related attitudes and behaviors including violence, eating disorders, and tobacco and alcohol use. One largely unexplored factor that may contribute to adolescents' sexual activity is their exposure to mass media.

    Objective. We sought to determine of what is and is not known on a scientific basis of the effects of mass media on adolescent sexual attitudes and behaviors.

    Method. We performed an extensive, systematic review of the relevant biomedical and social science literature and other sources on the sexual content of various mass media, the exposure of adolescents to that media, the effects of that exposure on the adolescents' sexual attitudes and behaviors, and ways to mitigate those effects. Inclusion criteria were: published in 1983–2004, inclusive; published in English; peer-reviewed (for effects) or otherwise authoritative (for content and exposure); and a study population of American adolescents 11 to 19 years old or comparable groups in other postindustrial English-speaking countries. Excluded from the study were populations drawn from college students.

    Results. Although television is subject to ongoing tracking of its sexual content, other media are terra incognita. Data regarding adolescent exposure to various media are, for the most part, severely dated. Few studies have examined the effects of mass media on adolescent sexual attitudes and behaviors: only 12 of 2522 research-related documents (<1%) involving media and youth addressed effects, 10 of which were peer reviewed. None can serve as the grounding for evidence-based public policy. These studies are limited in their generalizability by their cross-sectional study designs, limited sampling designs, and small sample sizes. In addition, we do not know the long-term effectiveness of various social-cultural, technologic, and media approaches to minimizing that exposure (eg, V-Chips on television, Internet-filtering-software, parental supervision, rating systems) or minimizing the effects of that exposure (eg, media-literacy programs).

    Conclusions. Research needs to include development of well-specified and robust research measures and methodologies; ongoing national surveillance of the sexual content of media and the exposure of various demographic subgroups of adolescents to that content; and longitudinal studies of the effects of that exposure on the sexual decision-making, attitudes, and behaviors of those subgroups. Additional specific research foci involve the success of various types of controls in limiting exposure and the mitigative effects of, for example, parental influence and best-practice media-literacy programs.

    Key Words: adolescent sexual behavior attitudes media impact

    Abbreviations: STI, sexually transmitted infection HPV, human papillomavirus CDC, Centers for Disease Control and Prevention TV, television VCR, videocassette recorder NIH, National Institutes of Health

    INTRODUCTION

    Although the proportion of high school students who have had sex has declined in the past decade, many adolescents in the United States are engaging in sexual activity at early ages and with multiple partners. Approximately 47% of high school students have had sexual intercourse.1 Of these, 7.4% report having sex before the age of 13 and 14% have had 4 sexual partners.1

    Sexually active adolescents are at immediate risk for pregnancy and acquiring sexually transmitted infections (STIs). Each year, nearly 900000 teenaged girls in the United States become pregnant (340000 are 17 years old),2 and 35% of American teenaged girls have been pregnant at least once by the age of 20.2 In the United States, the risk of acquiring an STI is higher among teenagers than among adults.3 Almost 4 million cases of STIs are diagnosed in adolescents each year.4 In 2002, gonorrhea rates in the United States were highest among females in the age brackets of 15 to 19 years (675.6 per 100000) and 20 to 24 years (650.3 per 100000); among males those in the 20- to 24-year age bracket had the highest rate (538.1 per 100000).5 The most common reported STI in the United States is chlamydia, and it is most prevalent among adolescents. In 2002 chlamydia prevalence reported among sexually active adolescent females was 6 times as high as that among sexually active females in the general population.6 Human papillomavirus (HPV) infection is the most prevalent of all viral STIs, even more common than herpes simplex virus and human immunodeficiency virus (HIV) combined. Approximately 35 of the 100 known HPV strains cause cervical cancer; the remainder cause genital warts. HPV seroprevalence is 5% in adolescents aged 12 to 19 and 15% among young adults aged 20 to 29. High levels of HPV infection are found among high-risk teens: 1 study of inner-city teens found 24% of young women were infected with HPV.4 HIV is the causative agent in acquired immunodeficiency syndrome (AIDS). In 2000, >2900 new HIV cases diagnosed in young people aged 15 to 24 were reported to the Centers for Disease Control and Prevention (CDC) from just 30 states. Given that it typically takes a decade after HIV infection for AIDS symptoms to appear, it is likely that most young adults diagnosed with HIV infection and AIDS had been infected with HIV as adolescents. By the end of 2002, >36000 cases of HIV/AIDS had been reported in young people aged 13 to 24 in the United States.7,8 By the end of 2001 >14000 young Americans aged 15 to 24 had died of AIDS, according to the most recent CDC data available.7

    Data suggest that sexually active adolescents are at high risk for depression and suicide.9–12 Early sexual experience among adolescents has also been associated with other potentially health-endangering behaviors such as alcohol, marijuana, and other drug use.12

    Many factors may put teens at risk for becoming sexually active at an early age. Some of the most important risk factors are race, poverty, the use of drugs and alcohol, peer influences, and parental influences.13

    One potential but largely unexplored factor that may contribute to sexual activity among adolescents is exposure to sexual content in the mass media. The average American youth spends one third of each day exposed to media, and the majority of that exposure occurs outside of parental oversight.14 Although mass media have been shown to have an influence on a broad range of behaviors and attitudes including violence, eating disorders, tobacco and alcohol use, surprisingly few studies have examined the effects of mass media on adolescent sexual attitudes and behaviors. This report is a review of those studies.

    Theoretical Perspectives: Media as an Influence on Attitudes and Behaviors

    The potential for mass media to influence behavior has been supported through a number of different psychosocial theories, hypotheses, and models. Although there is considerable variation in theoretical mechanisms by which media might affect adolescents' sexual attitudes and behaviors, most posit that sexually related message content and behavior act over time as stimuli to change consumer psychological, physiologic, and behavioral function.

    Social-Learning Theory

    Bandura's social-learning theory,15 one of the most prominent of these theoretical mechanisms, provides ample evidence that even when children and adults have not actually performed a behavior, they can learn by imitation. Bandura identifies 3 main processes involved in learning: direct experience, indirect or vicarious experience from observing others (modeling), and the storing and processing of complex information through cognitive operations. This theory suggests that behaviors are learned and that they are influenced by social context: "Television is seen as an increasingly influential agent of socialization that produces its effects through children's propensity to learn by imitation."16

    Disinhibition Theory

    Disinhibition theory posits that existing behavioral tendencies of children and others are inhibited by experience.17 Continued exposure to television (TV), however, disinhibits viewers, making them more accepting of the behavior.18

    Priming Theory

    Research has shown that exposure to an event (ie, sexual stereotypes) from the mass media activates other similar ideas for a short time afterward.19 These thoughts, in turn, can activate other semantically related concepts and make them more accessible.

    Arousal Theory

    Arousal theory focuses primarily on the immediate effects that sexually suggestive material may have on behavior.20 TV content, for example, can produce general emotional and physiologic arousal (ie, activation of the nervous system rather than specific sexual arousal) that is likely to elicit some type of individual and contextual behavioral response.

    Cultivation Theory

    Cultivation theory posits that heavy exposure to mass media creates and cultivates attitudes more consistent with a media-directed version of reality than with reality itself.21 Media portrayals and messages might affect the behavior of young persons over time by enabling them to acquire new attitudes and behaviors or by changing the likelihood that they will perform new or previously learned responses. This may occur when a child's expectations about the outcome of certain behaviors are altered through identification with the character portraying or providing the stimuli, by raising or lowering behavioral inhibitions, by modifying the potential for environmental cues to foster certain behaviors, or by linking specific meanings to a behavior.

    Media Practice Model

    This model was developed to explain media use in a comprehensive and contextual framework22 and highlights the connections between adolescents' identities and media selection, interaction, and application22: "This model assumes that youth choose media and interact with it based on who they are or who they want to be at the moment."23 Theoretical research is borne out by communications-related survey data. Advertisers recognize that the content of their messages will have an effect on consumer purchasing behavior.24 Additionally, young people report that media messages are an important influence in their lives25 and that they receive important information about life choices from the media.26

    Third-Person Effect Hypothesis

    The third-person effect hypothesis states that people tend to perceive mass media messages to have a greater impact on others attitudes and behaviors than on themselves.27 A practical way of looking at third-person effect is that messages "have little effect on people like you and me, but the ordinary reader is likely to be influenced a lot." This phenomenon may be exacerbated for adolescents and may lead to underreporting of decision-making factors.

    Super-Peer Theory

    This theory posits that the media can represent a potent source of information for teens as to what is normative behavior28,29 and may indeed exceed the influence of an adolescent's more traditional peer group.30 The effect of exposure to attitudes and behaviors portrayed in mass media may be compounded by the glamour typically associated with those appearing in it (both the characters and the actors playing them). Moreover, TV programming targeted to youth takes advantage of the attraction of children and teens to characters they perceive to be 2 or 3 years older than they themselves are31—"peers" with whom they typically cannot socialize but whom they long to be like. Such characters, although older than the child's peer group, provide templates for the child's "aspirational" behavior.31 In short, youngsters model themselves after those who they want to be not those who reflect who and what they currently are.

    Power of the Indirect

    Whatever the correct theoretical underpinning(s), data suggest that messages embedded in other media types are more powerful than direct advertising appeals when it comes to influencing behavior. Advertising is influential, but perhaps because teens have now become more marketing savvy, they tend to resist direct appeals to change their behaviors and are better persuaded by subtle, embedded messages.32 The result has been greater use of nontraditional marketing approaches such as "viral" marketing (any strategy that encourages individuals to pass on a marketing message to others), using "trend-setters" as communication sources, and e-mail. Such nontraditional sources de-emphasize the advertising aspect and highlight content to minimize the consumer's sense of being manipulated, which explains why product placement is so popular in movies and TV: it is indirect and subtle but powerful.32 The National Youth Anti-Drug Media Campaign (sponsored by the Office of National Drug Control Policy) conducted a qualitative and ethnographic study throughout the country in 6 markets during August 2003. Teens were asked to use a diary to keep track of all drug messages (prodrug and antidrug) with which they came into contact across all media sources for a 2-week period, after which focus groups were held. The main finding was that prodrug messages were perceived by all teens as more powerful and compelling than antidrug messages primarily because of their subtlety and embedded nature.33

    Media Influence on Other Health-Related Behaviors

    Although little is known about the effect of mass media on adolescent sexual behaviors, much more is known about its effects on other health-related behaviors. In particular, violence in mass media has attracted a great deal of ongoing attention.34 The effects of a child or adolescent's media diet on their future risk of eating disorders and alcohol and tobacco use have also been subjects for study. What follows is a brief summary, not a thorough survey, of the effects that mass media has on other health-related behaviors in adolescents.

    Aggressive Behavior

    Youth violence as a public health issue was addressed in a 2001 report by the US Surgeon General.35 Numerous studies have investigated the association between media violence and aggression, with many focusing on children and adolescents. A variety of study designs have been used to understand the media-aggression relationship, including laboratory,36,37 correlational,38–41 longitudinal,42–47 and ecological designs.48 Several comprehensive reviews of youth literature are available.49–54 Most of these studies have supported a positive association between exposure to media violence and aggression. The association has been strong enough to cause congressional concern and the creation of a series of Federal Trade Commission reports.34

    Eating Disorders

    The prevalence of obesity is increasing in the United States.55 Researchers have repeatedly found a significant association between obesity and TV viewing.56–61 From 1963 through 1965, Dietz and Gortmaker56 studied 6965 children aged 6 to 11. Results showed that children who watched more TV experienced a greater prevalence of obesity or superobesity than children watching less TV. Crespo et al examined the relationship between TV watching, energy intake, physical activity, and obesity status by using a national representative sample of US children aged 8 to 16 (interviews were done between 1988 and 1994). They reported that the prevalence of obesity was lowest among children watching 1 hours of TV per day and highest among those watching 4 hours of TV per day. TV watching was positively associated with obesity among girls even after controlling for age, race/ethnicity, family income, weekly physical activity, and energy intake.61 In a 1990 study of a cohort of 746 youths aged 10 to 15, Gortmaker et al59 had similar results, finding a strong relationship between the prevalence of overweight and hours of TV viewed.

    Depending on the methodology used, the reported prevalence rate for anorexia nervosa and bulimia nervosa among adolescent females ranges from 2.4%62 to 5%63 and is 0.48% among girls aged 15 to 19 for anorexia alone.64 Although males comprise only 10% of anorexia cases, both genders are experiencing an increase in prevalence of eating disorders.65 Of particular concern is that eating disorders in early childhood are associated with symptoms of bulimic behaviors in adulthood.66 Martinez-González et al67 found a positive association between the incidence of eating disorders and weekend TV viewing in a sample of females aged 12 to 21. They also found that those adolescent females at higher risk of developing an eating disorder (based on Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria) were also more likely to read girls' magazines or listen to radio programs (odds ratio: 2.1; 95% confidence interval: 1.2–3.8, for those most frequently using both media).67 Other research has shown that among 374 girls (mean: 12 years old), over a 16-month period those who reported increased eating-disorder symptomatology had significantly increased their exposure to fashion magazines but decreased their number of hours of TV viewing, whereas those with decreased symptomatology had significantly decreased their exposure to both TV and fashion magazines.68 Trying to look like females portrayed on TV, in movies, or in magazines was also significantly predictive of preadolescent and adolescent girls' onset of eating-disorder–related behavior (odds ratio: 1.9; 95% confidence interval: 1.6–2.3). A study comparing 2 samples of Fijian schoolgirls before and after the introduction of TV to the region is suggestive: indicators of disordered eating were significantly more prevalent after prolonged exposure to TV. Study participants reported a desire to lose weight or to reshape their body to become more like Western TV characters.69

    Tobacco and Alcohol Use

    Each day 4000 children <18 years old smoke tobacco for the first time,70 nearly 2000 of which will become regular smokers. It is estimated that at least 4.5 million US adolescents are cigarette smokers. Approximately 80% of smokers begin smoking before the age of 18.71 Several studies have explored the impact of advertising on adolescents.72–74 Many have shown advertising to be very effective in increasing youngsters' awareness of and emotional responses to products (recognition of brands, desire to own the products advertised). Cigarette advertising seems to increase teenagers' risk of smoking by glamorizing smoking and smokers,75 and children who are able to recall ads related to tobacco are more likely to view smoking favorably and to become smokers.72–74

    Alcoholic drinks are the most common beverages portrayed on TV.29 It has been shown that exposure to alcohol advertising and TV programming is associated with positive beliefs about alcohol consumption.76–78 Although such cross-sectional studies do not prove causation (only association), it is of interest that in a 1990 study, 56% of students in grades 5 to 12 said that alcohol advertising encourages them to drink.79 A longitudinal study examined the association between alcohol consumption at the age of 18 and alcohol-related messages at the ages of 13 and 15. Findings showed that girls who had watched more hours of TV at ages 13 and 15 drank more wine and spirits at age 18 than those who had watched fewer hours of TV.80

    A 1997 study of >300 Web sites found that 25 major alcoholic beverage companies were even then using the Internet to advertise, promote, and sell their products through a variety of marketing techniques that capitalize on the Internet's strong attraction for young people.81

    Strasburger's 2002 review29 (which also includes data of interest regarding representations of smoking and illicit drug use) concludes that "[a]lthough the research is not yet scientifically ‘beyond a reasonable doubt,’ a preponderance of evidence shows that alcohol advertising is a significant factor in adolescents' use of this drug."29(p361)

    Purpose of This Report

    Effects of the mass media have been found to be far-reaching and potentially harmful in influencing the health-related behaviors of children and adolescents, many of whom are not yet mature enough to distinguish fantasy from reality, particularly when it is presented as "real life." Furthermore, time spent with media decreases the amount of time available for pursuing other more healthful activities such as sports, physical activity, community service, cultural pursuits, and family time. The accumulation of evidence across multiple health-risk behaviors suggests that media influence on youth is worthy of careful research.

    This report presents the results of a review of the literature and other data sources on the impact of mass media (including the Internet) on the sexual attitudes and behaviors of adolescents (ages 11–19) in the United States. For each form of media we include the scientific data from the last 2 decades (1983–2004) on adolescent exposure to that medium, its sexual content, and the effects of that exposure. The report concludes with an assessment of future research needs.

    METHODS

    Definitions

    This study examines the exposure, content, and effect of media on adolescent sexual attitudes and behaviors. For this study "exposure" refers to the amount of time per day spent with different types of media and the social context of media use. "Content" refers to any dialogue, situation, or behavior that involves sexuality, sexual suggestiveness, or sexual activities or relationships, as well as the nature of sexual depictions in the media.

    Studies define "sexual behavior" in a wide variety of ways: is a kiss sexual Is dating Many studies use the term "explicit" to mean "overt" (the opposite of "implied") rather than to indicate, eg, a degree of nudity or level of physical intimacy. The majority of recent studies make use of the definitions created for the Kaiser Family Foundation's ongoing Sex on TV82–84 studies:

    "[S]exual content is defined as any depiction of sexual activity, sexually suggestive behavior, or talk about sexuality or sexual activity. Portrayals involving only talk about sex are measured separately from those that include sexual actions or behaviors.... To be considered a sexual behavior, actions must convey a sense of potential or likely sexual intimacy. For example, a kiss of greeting between two friends or relatives would not be coded as sexual behavior, whereas a passionate kiss between two characters with a discernible romantic interest would be. The lower threshold for sexual behaviors measured by the study was physical flirting, which refers to behavioral actions intended to arouse sexual interest in others, such as a woman licking her lips provocatively while gazing intently at a man in a bar."84(p7)

    "Sexual dialogue, or what we term ‘talk about sex,’ involves a wide range of types of conversations that may involve first-hand discussion of sexual interests and topics with potential partners, as well as second-hand exchanges with others that convey information about one's prior, anticipated, or even desired future sexual activities. For purposes of measuring talk about sex, both the topic of reproductive issues (such as contraception or abortion) and sexually transmitted diseases (including but not limited to AIDS) were considered as sexual."84(p8)

    "Intercourse implied is said to occur when a program portrays one or more scenes immediately adjacent (considering both place and time) to an act of sexual intercourse that is clearly inferred by narrative device. Common examples would include a couple kissing, groping, and undressing one another as they stumble into a darkened bedroom, with the scene dissolving before the actual act of intercourse ensues; or a couple shown awakening in bed together with their conversation centering on the lovemaking they had performed before falling asleep. Such portrayals are not necessarily explicit in any way but clearly convey the message that sex has occurred, and thus it is essential that such portrayals be reflected in our content measures."84(p8)

    "[I]ntercourse depicted is judged to occur when a direct view is shown of any person who is engaged in the act of intercourse, regardless of the degree of nudity or explicitness presented. Discreet portrayals may show a couple only from the shoulders up when they are engaged in intercourse."84(p8)

    "Effect" refers to the influence of media content on adolescents' attitudes and behaviors. We use the term "sexual attitudes and behaviors" to include beliefs, values, and decision-making, as well as attitudes and behaviors.

    "Adolescents" and its cognates are variously defined, as are the exact boundaries of "teenagers" and "youth." The lines between childhood, adolescence, and adulthood may differ by culture and region. The World Health Organization defines "true adolescence" as "the period of physical, psychological and social maturing from childhood to adulthood," which may occur anywhere between the ages of 10 and 24.85 The CDC uses the terms "adolescents and young adults" for those aged 10 to 24, inclusive,86 usually broken into 3 age groups (ages 10–14, 15–19, and 20–24). At the same time, the US National Library of Medicine, in its Medical Subject Headings (MeSH terms), defines the adolescent as "a person 13 to 18 years of age," whereas the PsycInfo database uses the ages of 13 through 17. Although teenagers may legally be adults at the age of 18, they are not for the most part adults developmentally, emotionally, behaviorally, or socially; most high school seniors are living at home with their parents. For purposes of this study, "adolescents" are those 11 to 19 years old, and the terms "teens," "teenagers," and "youth" may be considered synonyms.

    Inclusion Criteria

    Materials were restricted to those published in English from 1983 to 2004 (ie, the last 21 years) with respect to youth aged 11 to 19 in the United States. In addition, some studies from other postindustrial English-speaking populations (eg, Canada and the United Kingdom) were included when their results seemed likely to be relevant or generalizable. Materials had to be peer reviewed (for effects) or otherwise authoritative (for content and exposure), which excluded 2 effects studies that were dissertations.87,88

    Literature Search and Other Data Sources

    Multiple data sources were used to identify relevant materials or research documents containing references to sexual exposure, content, and effect. The scientific literature was searched through the standard indexing databases for various fields by using appropriate indexing terms when controlled vocabularies were in use and a variety of key words when standardized topic references were not available. Government documents and congressional testimony, the World Wide Web, books and other printed materials, and unpublished materials were also sought (see Table 1 for details).

    Preliminary lists of possibly relevant literature were reviewed at the abstracts level (when available; by title when not available) to exclude those pertaining, for example, to studies that made use of mass media as a deliberate intervention tool (eg, anti–sexually transmitted disease campaigns broadcast as public-service announcements). Opinion pieces or other material lacking scientific data were not considered relevant to this review, although policy recommendations from such groups as the American Academy of Pediatrics were relevant. Items were entered into a Reference Manager 10.0.01 database, which allowed the automatic culling of duplicates; materials then were obtained, reviewed for relevance, and (if relevant) summarized. Those items available online were downloaded as Adobe PDF or text files; others were photocopied from the source journal or obtained through interlibrary loan. Those that were found relevant on reading are included in this report.

    Examination of all data sources revealed 2522 documents that addressed sexual content, exposure, or effect. The vast majority addressed exposure or content; only 12 addressed effects, 10 of which were peer-reviewed, eligible studies.

    Excluded Studies

    The vast majority of the material so found proved not to be relevant. As an example, PsycInfo was originally searched for items indexed with the term "adolescent" (45461 hits) and published 1983–2003 (36910) in English (34215) and then crossed with the term "media" (which includes "mass media"). Of the resulting 653 items, a preliminary inspection of title and abstracts revealed only 24 that addressed exposure, content, or effect. Only 4 of these 24 proved relevant to this study.

    Several studies that might otherwise have been included fall outside this report's scope because they focus primarily on college-age students or other adults. Examples include Strouse and Buerkel-Rothfuss,89 Calfin et al,90 Ward and Rivadeneyra,91 Ward,92 and Aubrey et al,93 all of whom studied college students. Other studies such as the Kaiser Family Foundation report released late in 200494 looked at those younger than our targeted age range (ie, children <7 years old).

    RESULTS

    Overall Media Exposure

    The Kaiser Family Foundation released a study in 2004 that focused on the exposure of very young children (aged 0–6 years) to electronic and print media. A nationally representative random-digit-dial telephone survey of >1000 parents was conducted in the spring of 2003. The researchers found that 99% of the children live in a home with a TV set (one third had a TV in their bedroom); 73% have a computer at home; and 49% have a video-game player. By parental report, 97% have listened to music, 91% have watched TV, and nearly half (48%) have used a computer; these are children 6 years old! Parents reported that these children spend 2 hours per day with screen media, mostly TV and videos. Among 4- to 6-year-olds, 27% use a computer every day, spending an average of just over 1 hour at the keyboard.94

    Only a small number of national representative studies have examined comprehensive media exposure in 11- to 19-year-olds. Given the exposure of their youngest siblings, it is not surprising that the most recent data indicate that American adolescents spend an average of 6 to 7 hours per day with some form of media including TV, videotapes, movies, radio, print media, computers and the Internet, and video games.95 Many teens use multiple media simultaneously, such as listening to music while surfing the Web.95 Table 2 presents the estimates of average daily media exposure time from a 1999 nationally representative sample of 2065 young people aged 8 to 18,14 the most recent scientifically conducted national study of adolescent media use. The sample used a stratified, 2-stage national probability sample in which schools were selected randomly from a list of 80000 public, private, and parochial schools in the United States (stage 1), and grades and classes within grades were selected randomly to participate (stage 2).95 Their data on the contribution of each media type to total daily media exposure are represented in Fig 1.95

    There is growing concern that youth are accessing media in environments isolated from the supervision or guidance of parents or other adults. Table 3 presents findings from a national survey of American youngsters aged 8 to 18 concerning the type of media they report having in their bedroom.14 Information regarding the social context of their TV viewing (Table 4) and other media use (Table 5) shows significant differences between the 8- to 13-year-old and 14- to 18-year-old age groups.14

    The Teen Media Study used the US Department of Agriculture food-group pyramid as a basis for the "media-diet" concept.23 The 2001–2002 study among 3261 7th- and 8th-graders (12–15 years old) introduced a new measure of exposure to sexual media content called the "sexual-media diet," which took into account both the amount of time spent with 4 different media (TV, movies, music, and magazines) and the amount of sexual content in the specific vehicles (eg, programs, music albums).96,97 This research by Brown and Steele23,98 indicates that adolescents' media diets are governed primarily by the teen's developing sense of self and that their media diets differ greatly by gender and race.

    The following sections summarize the makeup of the media diet of American adolescents and what little we know of its consequences for their sexual attitudes and behaviors.

    Broadcast and Cable TV

    Exposure

    TV viewing among adolescents is pervasive, and many adolescents view TV alone, with or without adult input or monitoring.14 Virtually all households in the United States have at least 1 TV set, 69% have 3, and 98% have a videocassette recorder (VCR).95 In addition, two thirds of youth aged 8 to 18 report having a TV in their bedroom, and more than one third have their own VCR.14

    Approximately two thirds of US youth live in homes with cable TV.95 Among those aged 8 to 18, 74% reported that their home received cable or satellite TV, and 46% received premium channels. In addition, 30% of youth surveyed reported receiving cable/satellite channels in their bedrooms, with 15% receiving premium cable. Black youth (38%) are slightly more likely to report having a cable or satellite connection in their bedroom than white (29%) or Hispanic (31%) youth.14 Black youth report significantly higher cable TV viewing than white and Hispanic youth, watching 5.5 hours per week of MTV (Music Television), compared with 90 minutes per week for white youth, and 7.7 hours per week of BET (Black Entertainment Television) viewing.99 Teens tend to "channel-surf" through a wide variety of cable networks, with MTV being predominant; the advent of digital TV will expand the number of available cable channels to 400 to 500.100 Significant differences in cable viewing are apparent by gender. Among girls, the most popular cable stations include MTV, Disney, and the WB, whereas boys are more likely to watch Comedy Central, ESPN, and the Cartoon Network.99

    The average teenager spends >3 hours per day watching TV.14 Black youth report significantly higher overall daily TV viewing than other racial/ethnic groups, and black and Hispanic youth are substantially more likely than white youth to have a TV in their bedrooms.14 Approximately one fifth of those aged 8 to 13 and one third of those aged 14 to 18 report that their overall daily TV viewing occurs alone, without parents, siblings, or peers. Even during evening hours, when parents are more likely to be home, 32% of those aged 8 to 13 and 38% of those aged 14 to 18 report watching TV alone.14 In addition, seemingly few parents establish rules about when or what their children may view: only 38% of youngsters aged 8 to 18 reported having household rules about TV viewing.95 However, we do not know whether their parents would agree as to the absence of such rules, and the data are not recent enough to cover the effectiveness of such technologic restrictions as the V-Chip.

    Content

    Research evaluating the sexual content of TV indicates that it is pervasive and seems to have increased over the past 2 decades,83,101–103 perhaps cresting in 1998. In more recent years there are some indications of reductions in such content, at least during the broadcast networks' "family hour,"104 but the overall proportion of programs with sexual content continues to increase.84

    The Kaiser Family Foundation biennial studies (Table 8) are the only ongoing monitoring of sex on TV as a whole. Across the TV landscape, the overall proportion of programs with sexual content in 2001–2002 was significantly greater than that observed in 1997–1998.84 Over this time period, references to sexual intercourse became more frequent (including the portrayal of sexual behavior), the proportion of programs with depictions of sexual behavior rose, and the average number of scenes depicting sexual behavior increased.84

    Characters involved in sexual behavior in TV programs rarely experience any negative consequences. For example, in the most recent Kaiser Family Foundation study,84 programs with a primary emphasis on sexual risk and responsibility themes represent only 1% of all shows that contain sexual content, which means that 3 of the 200 programs in this study having intercourse-related content placed primary emphasis on sexual risk or responsibility. Moreover, protection against STIs and unwanted pregnancy was observed in only 3% of all scenes with sexual content. Risks and negative consequences of sexual behavior were found in only 2% of all scenes with sexual content (specifically, 75 of 870 scenes of sexual behavior). Delaying sexual intercourse was depicted in only 1% of all scenes with sexual content.84 It therefore would seem that TV programming would be providing parents with many opportunities to "use controversial programming as a stepping-off point to initiate discussions about family values, violence, sex and sexuality, and drugs."109 "Would be" if adolescents watched TV with their parents, but as seen in Roberts' 2000 study14 (Table 4), they mostly do not.

    Effects

    Although we know a great deal about the sexual content of TV, we know relatively little about its effects (Table 9). Associational studies, while suggestive, are not evidence of causality. Only 2 studies have examined the relationship over time between exposure to TV and sexual behaviors in adolescents.16,110 In the first study, Peterson et al16 analyzed data from the first 2 waves of the National Survey of Children. The first wave was conducted in 1976–1977 and comprised 2301 children; the second wave was conducted in 1981 among 1423 from the first wave. Because this study used secondary analysis of existing data that were not intended to examine these relationships, it has serious methodologic flaws in the measurement of TV exposure and content as well as in the measurement of sexual-activity variables. Mixed results were reported indicating the total amount of TV viewing in early adolescence was suggestive of an association between amount of TV watched and early initiation of sexual intercourse; however, the results did not reach statistical significance.16

    Statistical significance is found in the work of Collins et al,110 who conducted a national longitudinal telephone survey in 2001 and 2002 of 1792 adolescents aged 12 to 17. They surveyed the participants twice, 1 year apart, and found important associations between the amount of sexual content viewed by adolescents and advances in their levels of sexual behavior during the subsequent year.110 As adolescents went from the 10th percentile to the 90th percentile in exposure to sexual content on TV, the likelihood they would begin to have sexual intercourse in the next 12 months doubled. It is notable that, in accordance with social-learning theory, the study found that exposure to talk about sex was associated with the same risk as exposure to more visually explicit programming.

    Initiation of various levels of sexual behavior increases as adolescents grow older. Collins et al110 found that watching TV with sexual content has the effect of artificially aging children: those who watched more than average (by 1 standard deviation) behaved, sexually, as though they were 9 to 17 months older and watched only average amounts. The 12-year-olds who watched the most had the sexual behaviors of the 14- and 15-year-olds who watched the least.

    The study also found that, at least for black adolescents, exposure to portrayals of sexual risks and of the need for sexual safety and delay of sexual behavior was related to lower levels of noncoital sexual behavior. However, such portrayals are so rare that no conclusions could be drawn about their effectiveness with respect to other ethnic groups. Moreover, the researchers knew of no theory that could explain why such an effect was present for black adolescents as distinct from other subgroups. The results therefore point to an area in need of focused research.110

    Although the limited duration (2 years) of this study limits its interpretive power in some respects, the authors were clear: the magnitude of their results were such that "a moderate shift in the average sexual content of adolescent TV viewing could have substantial effects on sexual behavior at the population level."110 However, they also cautioned that such a reduction might not be easy to effect and that an approach that does not try to change either the content of TV or teenage viewing habits might prove most workable (eg, parents watching TV with their children).110

    Other studies have examined the association between exposure to TV and sexual behaviors and attitudes toward sexual activity, but in a cross-sectional fashion. These correlational studies do not permit inferences to be made about a direct association but allow assessments of whether media is at all associated with sexual attitudes and behaviors. Results from these studies indicate that high school students in North Carolina who watched TV shows with high sexual content were more likely to have sexual intercourse than those viewing TV shows with a smaller proportion of sexual content.111 Research findings also indicate that adolescents who view more TV with sexual content tend to overestimate the frequency of certain sexual behaviors112,113 and have more permissive attitudes toward premarital sex.114 Youth who were exposed to content portraying sexual relations outside of marriage were less likely to rate these portrayals negatively, compared with youth exposed to content portraying sexual relations within marriage or scenes of nonsexual relations.113

    Although these studies provide support for an association between sexual content on TV and adolescent sexual attitudes and behaviors, because of the cross-sectional design of the studies the direction of the influence is unknown. For example, it has been reported that sexually experienced students are more likely to seek out sexual content on TV than nonsexually experienced youth.111 In addition, most studies are seriously limited by small samples and restricted sampling frames.

    Although experimental evidence is generally considered the gold standard for establishing a causal relationship between exposure variables and outcomes, methodologic and ethical considerations hinder the use of the experimental designs to assess these associations among youth.115 For example, it is generally considered unethical to expose youth to sexually explicit materials, and therefore most experimental studies are conducted among college students, threatening generalizability of the findings to younger, non–college populations. "Natural experiments" such as the 1995 introduction of broadcast TV to a media-naive population in Fiji69 are rare; their results, although certainly suggestive, may not be generalizable to media-saturated American adolescents. Moreover, experimental studies most often involve short-term exposures of specific programming and thus cannot determine the effects of long-term cumulative exposures over time. The question of causality, therefore, must be answered by long-term longitudinal studies.

    Music Videos

    Exposure

    In a 1999 study, 10% of 8- to 18-year-olds reported watching music videos on the previous day.95 A study of 1533 9th-graders reported average exposure to music videos of 10 hours per week.116 MTV is the most popular TV network for young females and the fourth most popular for young males. Despite an increase in the amount of time dedicated to actual "programming" on MTV, 53% of all teens cite it as their preferred source for new music.99

    Content

    Depending on the music genre, one fifth to one half of music videos portray sexuality or eroticism.117,118 Often, music videos present visual images that are much more sexual than the music.119 Some studies from the 1980s analyzing the content of music videos indicated that sexual intimacy was shown in >60% to 75% of them, that there was an emphasis on sexual contact without commitment, that physical contact occurred at twice the rate it did on conventional TV, and that 81% of videos that showed violence also showed "sexual imagery."118,120 Another study from the same time period, however, indicated that only 47% (of 70 videos) had either visual or lyrical sexual references.114

    Effects

    As seen in Table 10, in a small 1986 study,114 adolescents who had just watched an hour of MTV videos were more likely to report approval of premarital sex than those who had not. A larger study 1 decade later121 found that adolescent girls showed a stronger relationship between exposure to music videos and attitudes relating to premarital sexual permissiveness than did adolescent boys, and that the association is even stronger for those girls with low rather than high family satisfaction. Again, however, the data do not determine a causal relationship, and the sample size and study design do not allow controlling for extraneous and confounding variables.

    Radio

    Exposure

    According to the Klein et al study122 published in Pediatrics in 1993, adolescents listened to radio nearly 40 hours per week, or nearly 6 hours per day. Roberts14 reported in 2000 that older adolescents (14- to 18-year-olds) tuned in an average of 65 minutes per day (7 hours, 35 minutes/week), and younger adolescents (8- to 13-year-olds) listened to an average of 35 minutes per day; overall, 8- to 18-year-old girls listened <7 hours/week and boys listened just 5 hours/week. The current level of exposure is unknown.

    As to the social context of this exposure, it is reported that during the week, adolescent radio listening is highest at 3 to 7 PM, whereas on weekends, teens listen the most from 10 AM to 3 PM. The majority of teens listen to radio either at home or in the car,123 and 86% report having a radio in their bedroom.14

    Content

    Radio stations targeting adolescent audiences have become highly specialized (eg, alternative rock, hot 100, top 40, rap, country/western).124 According to 1 study, among 12- to 19-year-olds, rap/hip-hop (44%) and top 40 (43%) radio stations are the most listened-to radio formats. Rhythm and blues and hard rock/heavy metal tie for third place (21% and 20%, respectively).99 However, few content analyses of radio programming have been conducted.125 A small study of 473 teen-oriented radio segments (15 hours) from the week of February 8 to 12, 1999, was conducted in the Minneapolis-St Paul market.126 Overall, 22% of radio segments contained sexual content. Each segment with sexual content was coded on a 4-point scale for amount of explicitness: not at all explicit, a little explicit, pretty explicit, and very explicit; some examples:

    "...It was so dumb/should'a used a condom.... Let him do his thing/I'm the one he's loving/I'm here to show y'all/having the kid ain't meaning nothing/That ain't keeping him/especially if he in love with another chick/then you're stuck with the infant mother shit" (Foxy Brown, My Life). The song was coded as sexual innuendo: pretty explicit, including discussion of responsibilities and consequences.

    "It's been three weeks since you've been looking for your friend/The one you let hit it and never called you again.... You act like you ain't hear him then gave him a little trim.... Plus when you give it up so easy you ain't even fooling him/If you did it then, then you probably fuck again.... The quick to shoot the semen stop acting like boys and be men." (Lauryn Hill, Doo Wop [That Thing]). The song was coded as direct discussion of sexual intercourse: very explicit, including discussion of planning, the benefits of sexual patience, and fidelity.

    Of the 100 segments coded as including sexual content, 20% were pretty explicit or very explicit. Very few segments included messages concerning planning or responsibilities (1%), consequences or risks (4%), or fidelity or monogamy (5%). Sexual content on the radio occurred during music segments (45%), during talk segments (30%), and during commercials (9%).126

    The small sample precludes generalizing. Moreover, these data are, in the fast-moving world of electronic media, dated. We do not know the current sexual content of those portions of radio programming to which various subgroups of adolescents listen.

    Effects

    Although most teens apparently listen to the radio every day, no studies of the effects of this exposure were identified.

    Music

    Exposure

    The amount of exposure to music media including radio, CDs, and audiotape cassettes doubles from early to late adolescence14 (see Table 2 and Fig 1). Among those aged 8 to 13, listening to radio, CDs, and audiotapes collectively comprises 17% of their total daily media exposure; among older teens (aged 14–18), it increases to 34% of the total, an average of >20 hours per week.14 Adolescents listen to music for several hours per day, usually as background music,122 and almost all teens have 1 sources of music in their bedroom.14 Among middle and high school students, rap/hip-hop and alternative rock are the dominant music genres. Boys are more than twice as likely as girls to listen to hard rock (27% vs 12%), whereas girls are more likely than boys to listen to gospel (11% vs 5%). White, black, and Hispanic youth have very different music preferences. Rap/hip-hop is more widely listened to by black (84%) and Hispanic (72%) youth than by white (43%) youth, whereas white and Hispanic youth are more likely to listen to alternative rock. White youth are more likely to listen to hard rock/heavy metal (24%) than black and Hispanic youth (2% and 12%, respectively).95

    Content

    A 1999 study of 10 top-selling music CDs indicated that of the 159 songs analyzed, 42% contained sexual content,126 41% of which were pretty explicit or very explicit (see examples in the preceding section).126 Again, the size and date of the sample preclude extending its results to the present.

    Effects

    No studies were identified that examined the effects of sexually explicit lyrics on adolescent sexual attitudes and behaviors.

    Movies

    Exposure

    Young people are a key marketing segment for the film industry: in a marketing survey of 12- to 17-year-olds, 20% report going to the movies 2 to 3 times per month during the past 3 months; 9% report going 1 per week.123 Black and Hispanic youth report greater exposure to movies than white youth.14 Teens usually do not go to the movies with their parents: 60% of 7th- to 12th-graders report going to the movies mainly with siblings or friends, and 15% report going mainly alone.14

    Although the Motion Picture Association of America will not reveal the current percentage of R-rated movies, that rating accounts for 58% of all movies made from 1968 to 2003 and 20% of the 20 top-grossing films in 2003.127 In 1993, most young people had viewed an R-rated movie long before they reached the required age of 16 (now 17).128 A 2004 Federal Trade Commission report revealed that, after widely publicized pressure on theater owners, only 36% of unaccompanied "mystery shoppers" <17 years old were able to buy theater tickets to see R-rated films; however, 81% of them were able to buy such films on DVD.34

    Content

    Although youth are a primary audience of Hollywood movies, few studies have assessed the sexual content of movies viewed by youth. Only 2 identified studies have analyzed the content of top movie videotape rentals and R-rated movies frequently viewed by young people.128,129 Both studies reported a high amount of sexual content, with the most common sexual activity occurring among unmarried partners. For example, the study of top movie videotape rentals of 1998 reported that 15% of scenes portraying sex occurred among married couples as compared with 85% among unmarried people. The most common sexual activity (45%) among unmarried partners was intercourse, and sexual behavior among married characters was rare and rather mundane compared with those having unmarried sex.129 A 1993 Greenberg et al128 study found that in 16 popular R-rated films seen by 14- and 15-year-olds, there were on average 17.5 scenes with "coded acts" and 10 instances of nudity per film. Coded acts included intercourse, long kisses, petting, and visual or verbal references to sexual activity. Although the majority of references to sexual intercourse were verbal, one third of all references had some visual component.128

    Although significant concern has been raised regarding adolescents' exposure to NC-17- (no one 17 and under admitted) and X-rated movies, limited data are available in this area. In a 1996–1999 study of sexually active black girls aged 14 to 18 years, 30% reported viewing an X-rated movie on videotape or in a theater in the previous 3 months.130

    Effects

    Few studies have assessed the effects of exposure to X- and NC-17-rated movies and on adolescent sexual attitudes and behaviors. In 2001, sexually active black female adolescents aged 14 to 18 who were exposed to X-rated movies were more likely to have multiple sexual partners, to have sex more frequently, to test positive for chlamydia, to have more negative attitudes toward using condoms, and to be less likely to use contraceptives.130 The cross-sectional research design, however, does not allow determination of causality, and it is unknown whether the results are generalizable to other subgroups of adolescents, such as other ethnic groups or males.130

    We do not know if the sexual content of R-rated movies has comparable effects and, if so, for which demographic groups.

    Magazines

    Exposure

    Data on magazine consumption also varies depending on the source; for example, data from an online marketing survey found that 48% of all teens read 1 or 2 magazines per month (P. Eitel, PhD, written communication regarding NeoPets.com online study, 2003). Another marketing survey found that 85% of teens have read or looked at a magazine in the last 6 months.131 Teen girls read magazines more frequently than teen boys, and each gender uses magazines for distinct purposes: girls read for style information, taking cues on fashion and beauty, whereas boys choose magazines that focus on their particular interests, mostly sports and gaming, followed by girls and music.99

    Content

    Teen-girl magazines include an average of >80 column inches per issue on sexual topics (1–6 articles). Content analysis indicates that magazines aimed at teen girls provide messages that girls should be beautiful and plan their lives to attract a man, and girls are depicted as objects of male sexual desire in editorial content as well as in advertising material.132–134

    Effects

    No studies have examined the effects of the sexual content of magazines (whether explicit adults-only or mainstream publications) on sexual attitudes and behaviors among adolescents, although some have theorized about the possibilities.134

    Advertising

    Teens are one of the fastest growing segments of the consumer population, having spent an estimated $170 billion in 2002. Marketers have focused attention on how to effectively capture and capitalize on adolescents spending power and have written publications (eg, Getting Wiser to Teens32) dedicated toward better understanding teen consumers and how to influence their decisions and purchasing behaviors. It must be noted that although advertising's intended effect is to change consumer purchasing behavior, its unintended side-effects can be both wide ranging and unpredictable.

    Exposure

    Advertising permeates almost all media to which teens attend, and exposure to advertising is pervasive.135 The average child sees an estimated 20000 advertisements each year. By the age of 12 years the average child has taken in 140000 messages, and by age 19 this number doubles to nearly 300000.32 These huge numbers have resulted in decreased attention to advertising and an increase in the marketing savvy of media-saturated teens, who therefore are less likely to be easily persuaded by advertising. At first glance this may seem positive, especially given the sexual (visual) content of advertisements selling everything from soda (eg, sexy bikini-clad "Fantanas" in Fanta commercials; Britney Spears' Pepsi commercials) to candy (eg, a girl who unwraps a Starburst with her tongue) to male body products (eg, Axe body-spray commercials). The data, however, refer predominantly to "traditional" methods of advertising such as TV, magazine, and radio advertisements. These do not take into account the nontraditional approaches that marketers are adopting to influence teens more effectively, approaches that are less easily measured and quantified. There is evidence that nontraditional advertising messages that feature embedded and subtle messaging may actually be even more influential, appealing, and powerful to teens33 (see "Power of the Indirect" above).

    Content

    There are little scientific data about the sexual content of either overt or embedded advertising. One study indicated that the proportion of undressed women in advertisements has changed little over the last 40 years, whereas the proportion of undressed men has increased significantly, especially since the early 1980s136; the impact of these increased portrayals of men has not been examined.

    Effects

    We do not know the effects of the sexual content of advertising on adolescent sexual attitudes and behaviors.

    Video and Computer Games

    Exposure

    The annual industry growth of the video and computer games industry in the United States has been meteoric, from $100 million in sales in 1985 to $10 billion in 2003.137 Of households surveyed in 1999, 70% reported having a video-game system; boys' homes (59%) were more likely than girls' homes (32%) to contain such a system, and boys were also more likely to have a video system in their bedroom than were girls (43% of boys versus 23% of girls).14 Black and Hispanic youth report greater exposure to video games than white youth, and black youth are more likely than white youth to have a video-game system in their bedroom.14 Fifty-five percent of those in grades 7 to 12 who play video games report playing mainly on their own or with siblings or friends (36%).14 Only 2% report playing with their parents.14 In a study of 7th- and 8th-graders, the average time spent playing video games was 4.2 hours per week. Boys played more frequently in video arcades (50% compared with only 20% of girls).138 A study of 1533 9th-graders reported average exposure to video games of 8 hours per week.116

    Among 8- to 18-year-olds, a significantly higher proportion of white (78%) than either black (55%) or Hispanic (48%) youth report living in computer-equipped households. Of these youth, approximately one fifth (21%) have a computer in their bedroom.14 Among youth who use computers, average daily computer use time ranges from 1 hour and 45 minutes among those 8 to 13 years old to 1 hour and 37 minutes among those 14 to 18 years old, with computer games claiming the largest share of leisure computer time. Older boys spend slightly more time with computers than do older girls, and Hispanic youth report more daily computer use (2 hours, 12 minutes/day) than either black (1 hour, 46 minutes/day) or white youth (1 hour, 35 minutes/day).14 Nearly two thirds (64%) of youth report playing computer games mainly alone.14 Almost half (49%) of teens who use computers report playing computer games (offline) and estimate spending 2.4 hours per week doing so. Another 53% report playing computer games online during the past week.139

    Content and Effects

    Despite the pervasive nature of exposure to video and computer games, no studies were identified that have examined the sexual content of video and computer games or the effects of exposure to that content on adolescent sexual attitudes and behaviors.

    The Internet

    Here the "Internet" includes e-mail, instant messaging, chat rooms, and the World Wide Web with its linkages and Web rings, including game- and music-download sites.

    Exposure

    It is expected that by 2010 most US homes with children will have access to the Internet.117 It has been estimated that in 2003, 60.8% of all US households (with and without children) had at least 1 desktop or laptop computer, and 92.7% of those (56.4% of all US households) had access to the Internet.127

    On average, 9- to 17-year-olds use the Internet 4 days per week and spend almost 2 hours online at a time.140 It is not well understood how much online exposure to sexual content is voluntary or involuntary. In 1 study of teens using computers, 61% reported "surfing the net," and 14% reported "seeing something they wouldn't want their parents to know about."100 Many of those who do not have computers or Internet access at home can log on at school.139 The majority of teens (88%) use the Internet at least once per month: 13% report accessing it daily; 13% more than once a day; 17% 1 to 2 times per week; 19% 3 to 6 times per week; and 26% less than once per week.123 The most frequent activities teens engage in online include e-mailing (74% read e-mail, 67% send e-mail), instant messaging (58%), listening to music (56%), and playing games (53%).139 A more recent study conducted by the Kaiser Family Foundation among 809 youngsters aged 10 to 17 in Silicon Valley, California, shows that 96% of them have gone online and most have at least basic access to computers and the Internet. Among those aged 14 to 17, 16% started using the Internet before age 10, and among those aged 10 to 13, 49% started using the Internet before age 10.141

    Teens are drawn to online activities that allow social interaction, entertainment, and information gathering.99 Girls are more likely to be social surfers, whereas boys tend toward entertainment and purchasing online. Overall, 75% of teens access the Internet at home, 60% access it at school, and 41% access it "somewhere else."99 The sites visited most often include Yahoo.com, Google.com, Hotmail.com, eBay.com, ESPN.com, and MTV.com.99 Sixty percent of youth report accessing chat rooms and Web sites mainly alone.14

    Internet file-sharing programs using peer-to-peer networks allow users to share and download files without charge. Users of Gnutella (ages unknown) shared 6.1 terabytes of data during the second and third weeks of October 2001.142 The pervasiveness of the technology and the sheer volume of (copyrighted) content being exchanged finally prompted legal action. The lawsuits filed by the Recording Industry Association of America (RIAA) have forced Napster to go from a file-sharing program to a fee-for-service Web site, but the Gnutella and Kazaa software packages are still freely distributed, and the ultimate effect is not yet known. In any case, the RIAA lawsuits affect only copyrighted music; they do not pertain, for instance, to pornography.

    Content

    Teens have access to a variety of adult-oriented Web sites on the Internet. Chat rooms, pornography sites, adult-video sites, and romance/dating services are but a few of the many and easily accessible "adult-oriented" materials to be found. Studies indicate that of the 1000 most-visited sites, 10% are adult-sex–oriented. In addition, portrayals of violent pornography on the Internet have increased, and access to such material has become easier.143

    Pornographic Web sites offer both still photographs and X-rated videos of every level of visual (and auditory) explicitness; there is even the Internet equivalent of "phone sex," sometimes with a live video connection.100 Search engines such as Google allow the user to type in words and word combinations and get results in seconds. For example, using a search engine to type "sex pictures," in <1 second a researcher was given a list of >2 million relevant sites.144

    One 1999–2000 national survey found that 1 in 5 youths aged 10 to 17 had inadvertently encountered explicit sexual content, and 1 in 5 (19%) had been exposed to an unwanted sexual solicitation while online in the previous year.145 Moreover, 73% of these exposures occurred while the youth was searching or surfing the Internet, and 27% happened while opening e-mail or clicking on links in e-mail or an instant message. Most of the unwanted exposures (67%) happened while the youth was using the Internet at home, but 15% happened at school, and 3% happened in libraries. The remainder occurred at other people's homes and other locations.145 Most of the imagery was simply of naked persons, but 32% showed people having sex, and 7% involved violence in addition to the nudity and sex.146

    Effects

    Although most teens have access to the Internet, no studies were identified that have examined the effects of Internet use (e-mail, instant messaging, or surfing the Web) on adolescent sexual attitudes and behaviors.

    DISCUSSION

    Although numerous studies have demonstrated the effects of media on various behaviors, including violence and aggression, social stereotyping, and prosocial behaviors,13 the systematic process of examining sexual content in the media and its impact on adolescent sexual behaviors is in its infancy.13 Several studies16,111,112,114,121,134 have demonstrated clearly that sexual content is pervasive in TV programming, movies, music videos, and magazines; however, much less is known about sexual content on the radio (including remarks by disc jockeys) and the sexual content of video and computer games. It is surprising that only a few studies have assessed the sexual content of the Internet or cable TV, and none have specifically examined this content in relation to adolescent exposure. This is particularly troublesome given that what little evidence there is indicates that the Internet and cable TV may contain the most sexually explicit content.28,100,143 Additionally, few studies have examined the sexual content of music, a medium that reaches virtually all adolescents.

    Most studies conducted to date on the effects of sexual content in the media on adolescent sexual attitudes and behaviors have restricted their focus to the influence of TV exposure. Research findings indicate that adolescents who view more TV with sexual content tend to overestimate sexual behaviors112,113 and to have more permissive attitudes toward premarital sex.114 Although these studies suggest an association between media exposure and adolescent sexual behaviors, they are limited because of their cross-sectional study design,111,112,114 limited sampling designs, and small sample sizes. A more recent longitudinal study found a significant association between frequency of sexual content in TV programs viewed and likelihood of initiation of sexual intercourse, as well as progressive engagement in more advanced noncoital sexual behavior.110

    Until recently, no studies have examined the effects of exposure to radio, music, music videos, cable TV, or the Internet on adolescent sexual attitudes and behaviors. Moreover, no previous study has examined the cumulative effects of multiple media exposures or the pattern of exposures on adolescent sexual behaviors. Brown et al23 devised a new measure for determining the sexual content of 4 types of media: TV, movies, CDs, and magazines. Using the sexual-media–diet measure, these researchers report that among adolescents, heavier exposure to sexual content is associated with increased sexual activity and intentions to become sexually active.23,97

    The existing evidence on media exposure clearly shows that black and Hispanic adolescents have higher levels of exposure to TV, videotapes, movies, video games, and radio.14 Black and Hispanic youth also have the highest prevalence of sexual behaviors as well as STIs and nonmarital pregnancies,1 whereas few existing studies on media exposure and sexual beliefs and behaviors have targeted these at-risk groups.

    Most studies conducted to date have failed to examine multiple sexual-related outcomes such as early initiation of sex, number of sexual partners, sexual beliefs, and intentions to have sex. Additionally, sexual behaviors such as oral sex have been ignored as potential outcomes affected by media exposure. Although few data exist on the prevalence of oral sex, a recent study indicated that 40% of youth report ever engaging in oral sex.147 To date, no studies have been conducted to assess the effects of media exposure on oral sex among adolescents.

    Several ongoing studies regarding the effects of adolescent exposure to sexual content in media have been funded by the National Institutes of Health (NIH) and the CDC, but they have not yet yielded published findings (see Appendix). Among these are 3 short-term longitudinal studies (cohorts followed for 2–3 years) funded by the NIH (D. L. Tolman, EdD, J. D. Brown, PhD, and R. J. DiClemente, PhD, unpublished data, 1999) and 1 long-term (10-year) study funded by the CDC (M. Windle, PhD, Grunbaum JA, EdD, Elliott M, PhD, et al, unpublished data, 1999). Two other NIH-funded studies (J. W. Grube, PhD, and M. Fishbein, PhD, unpublished data, 1999) are funded for 5 years but do not specify in their abstracts the timing of their measurements. Study-population sizes range from 5250 (the Healthy Passages study) to a "probability sample" of 865 in DiClemente's work. Only 2 studies will be looking at the youngest adolescents. One study is looking specifically at the World Wide Web, 2 are addressing only TV, and the remaining 3 are looking at multiple mass media.

    FUTURE DIRECTIONS

    Based on this review of the scientific evidence, we have identified many gaps in our knowledge of the sexual content of various media, the amount of exposure to it by adolescents, and the impact of this exposure. Although studies have documented exposure to sexual content in some types of media such as TV, music, and movies, there is a clear dearth of information about the extent and sexual content in other types of media such as radio, advertising, and the Internet. Moreover, there is a noticeable scarcity of well-conducted, scientifically rigorous studies that examine the impact of sexual content in the media on sexual behaviors among adolescents, and there are no studies that have longitudinally examined the cumulative effects of sexual content in different types of media.

    It is critical that longitudinal research be conducted, and within the multilevel context of child development: different groups of adolescents (defined by age, geographic location, ethnicity, domestic situation, and other variables) have different media diets, and identical diets may have differing effects depending on a number of factors. Long-term studies, although expensive, are the best way to discover if, for example, exposure to certain types of media content at age 12 has a greater impact on an adolescent's later sexual behavior than similar exposure at age 16 or if there is a multiplier effect from repeated exposures across multiple media platforms over time.

    Other research needs include the development of well-specified and robust research measures and methodologies as well as ongoing national surveillance of both the sexual content of media and the exposure of various demographic subgroups of adolescents to that content. Such measures need to be specific enough to yield workable data; defining any portrayal of dating as "sexual content" yields alarming statistics but no sound basis for public policy.

    Additional needed research foci involve the success of various types of controls (eg, V-Chips) in limiting exposure and the mitigative effects of such factors as parental influence and best-practice media-literacy programs.

    Based on this review, future studies should:

    Refine methodologies to measure (1) exposure to various media and (2) exposure to sexual content in those media: Research is needed to define measurement methodology to assess cumulative exposure across the various media types and patterns of exposure, and standard construct measures need to be adopted for future studies.

    Survey both children and adolescents to determine their exposure to all forms of mass media for which data are lacking: Studies are needed to address the huge gaps in current scientific evidence, including exposure to and sexual content of radio, music, computer and video games, the Internet, cable TV, and movies seen at home on VCR and DVD. One approach might be to add valid and reliable (for children and youth) measures13 regarding media exposure to existing surveillance studies, eg, the Youth Risk Behavior Survey,148 the Behavioral Risk Factor Surveillance System,149 or the Healthy Passages study.

    Conduct ongoing national surveillance of the sexual content of mass media: Such surveillance is currently provided biennially by the Kaiser Family Foundation regarding national TV broadcasting (including cable).82–84 There are no similar ongoing studies of other media.

    Survey parents, children, and adolescents to assess the effectiveness of parental involvement, communication, supervision, and monitoring of media sexual content: The effectiveness of parental involvement in relation to their children's exposure to media should be elucidated by using longitudinal study designs. Additionally, intervention studies should be conducted to examine if increased parental involvement, communication, supervision, and monitoring of sexual content in the media can influence the sexual attitudes and behaviors of adolescents.

    Evaluate child, adolescent, and parent media-literacy education to determine best-practice interventions and their impact on youth viewing choices, interpretation of content, and sexual attitudes and behaviors: Intervention studies are needed to examine whether current media-literacy education has an impact on adolescent sexual attitudes, decision-making, and behaviors and how such programs may be improved to best protect children and youth.

    Evaluate the effectiveness of other technologic, sociobehavioral, and media practices in limiting exposure of youth to explicit sexual content: The interventions include, eg, V-Chips and rating systems. Researchers such as those on the Task Force on Community Preventive Services150 could systematically review and conduct meta-analyses of population-based interventions. These data can then guide future development or refinement of, eg, user-friendly technologic approaches to parental controls on TV, the Internet, and other electronic devices.

    Evaluate the effects of mass media on child and adolescent sexual attitudes and behaviors: Longitudinal studies are needed that

    begin at earlier ages;

    are large enough to target multiethnic populations;

    address a wide range of determinants of sexual behaviors;

    examine multiple sexual-related outcomes including early initiation of sexual intercourse, number of sexual partners, contraceptive and condom use, STI and nonmarital pregnancy rates, other sexual behaviors such as oral sex, dating violence, and sexual violence;

    address potential mediating variables such as age, puberty, peer factors, and family factors (eg, parental supervision and monitoring of media use); and

    have a follow-up period long enough to examine long-term cumulative effects.

    Only in such ways can we determine the effects of mass media on adolescent sexual attitudes and behaviors.

    APPENDIX: CURRENT LONGITUDINAL STUDIES ON THE INFLUENCE OF MASS MEDIA ON ADOLESCENT SEXUAL BEHAVIORS

    Information presented in this appendix was adapted from the Computer Retrieval of Information on Scientific Projects (CRISP) database (http://crisp.cit.nih.gov) and other sources.

    Healthy Passages

    Principal Investigators and Funding

    Principal investigators: Michael Windle (University of Alabama, Birmingham, AL), Mark Schuster (University of California, Los Angeles, CA), Susan R. Tortolero (University of Texas Health Science Center, Houston, TX). Funding: CDC cooperative agreements CCU409679, CCU609653, and CCU915773.

    Study Information

    Healthy Passages is a longitudinal study of child and adolescent health with a prospective research design. Beginning in the fall of 2004, it will make biennial assessments of multiple health behaviors and outcomes in a cohort of 5250 5th-grade children, following them for 10 years. Focusing on both risk and protective factors, it will identify patterns of initiation and change in health behaviors across time. Among other multilevel environmental factors, the study will examine time spent on music, videotapes, Internet, and video games, TV content, and co-viewing, as well as how "real" children think TV shows are, how much they relate to their own lives, and parental involvement in media use. Assessment methods will include ratings from children, primary caregivers, and teachers; data from school records; and observations of school and neighborhood environments.

    TV Consumption and Adolescent Sexual Activity

    Principal Investigator and Funding

    Principal investigator: D.L. Tolman (Wellesley College, Wellesley, MA [currently at San Francisco State University, San Francisco, CA]). Funding: National Institute of Child Health and Human Development grant 1R01HD038393-01A1 (September 22, 2000, through August 31, 2005).

    Study Information

    This study will examine if TV programs influence adolescent's sexual beliefs and behaviors. It will follow 1 cohort of 8th-graders into 10th grade and another cohort of 10th-graders into 12th grade. The study will analyze the amount and proportion of sexual content viewed, the contextual elements of sexual content viewed, and adolescent involvement in the TV they have viewed. The role of TV consumption in adolescents' sexual beliefs and behaviors will be described qualitatively (not quantitatively), as will the ways in which adolescents make sense of the sexual content that they view, the significance and meanings that they attribute to this content, and their perceptions of how it affects their own sexual beliefs and decisions about sexual behavior (as revealed in content analyses of focus groups).

    Effects of Media on Adolescent AIDS-Related Behavior

    Principal Investigator and Funding

    Principal investigator: M. Fishbein (University of Pennsylvania, Philadelphia, PA). Funding: National Institute of Child Health and Human Development Grant 5R01HD044136-02 (September 3, 2002, through June 30, 2007).

    Study Information

    This is a 3-wave longitudinal study to examine the association between exposure to sexual content in the media (including TV, movies, music CDs, the Internet, video games, and magazines) and sexual behavior among young adolescents. It focuses on the media's role in presenting sexual content, implying sexual norms, modeling sexual decision-making ("self-efficacy"), and displaying the outcomes of sexual behaviors.

    Adolescent Sexuality and TV

    Principal Investigator and Funding

    Principal investigator: J.W. Grube (Pacific Institute for Research and Evaluation, Calverton, MD). National Institute of Child Health and Human Development Grant 5R01HD038906-05 (September 25, 2000, through June 30, 2005).

    Study Information

    This is a longitudinal study with the goal of determining if and under what circumstances sexually related content in TV programming predisposes young people to engage in sexual activity. Study 1 will be a content analysis of the sexual language and images in TV programming, documenting the nature and frequency of sexual content on TV overall by program type and genre. Study 2 will be a longitudinal survey of adolescents (aged 11–16 at wave 1) and their parents. The samples will be selected from the greater San Francisco Bay Area and from Los Angeles County using random-digit-dialing methods. The primary objective of study 2 is to investigate if exposure to, awareness of, and affect toward sexual content on TV influences changes in adolescent sexual knowledge, expectancies, norms, intentions, and behaviors. A secondary objective of study 2 is to test and extend a theoretical model of media effects that was developed in the context of alcohol advertising. This model specifies how the effects of exposure to media content on beliefs, knowledge, and behavior are mediated through affective and cognitive processes and how these relationships are moderated by important personal, environmental, and message variables.

    Mass Media and Adolescents' Sexual Health

    Principal Investigator and Funding

    Principal investigator: Jane D. Brown (University of North Carolina, Chapel Hill, NC). Funding: National Institute of Child Health and Human Development Grant 5R01HD038508-05 (September 26, 2000, through July 31, 2005).

    Study Information

    This is a longitudinal study with the goal of determining if there is a link between teens' exposure to sexual content in the media and their sexual beliefs and behaviors. The project is based on the Media Practice model that assumes that adolescents must choose among the array of media now available to them. Data will be gathered in 5 phases. First, all 7th- and 8th-grade students (3000) enrolled in 9 middle schools in central North Carolina will complete a self-administered questionnaire about their use of the mass media. Second, the content the teens most frequently attend in that medium to create a measure of their sexual-media diet: the time each teen spends attending to sexual content in the media. Third, a stratified (by race and gender) random sample of 1000 of the students who completed the in-school media questionnaire about their use of the mass media. Two years later, in phases 4 and 5 of the project, the 1000 students will be reinterviewed in their homes, and another sample of media content will be analyzed to assess how media diets and sexual attitudes and behaviors have changed. The longitudinal and comprehensive design of this study will provide the most current understanding of how the mass media affect the sexual beliefs and behaviors of adolescents.

    Teens and Exposure to HIV Risk on the Web

    Principal Investigator and Funding

    Principal investigator: Ralph J. DiClemente (Emory University). National Institute of Mental Health Grant 5R01MH063696-04 (July 1, 2001, through June 30, 2006).

    Study Information

    This prospective study will examine the effects of adolescents' exposure to Web pages that contain sexual content on the sexual health-related attitudes, beliefs, and behaviors of a national probability sample of 865 teens (615 white and 250 black male and female teens) 14 to 16 years of age. The aims are to (1) describe characteristics of teens who access Web pages that contain sexual health, sexually explicit, and sexually related content, (2) develop cross-sectional models examining the association between exposure to Web pages that contain sexual content and their sexual health-related knowledge, attitudes, beliefs, intentions, and behaviors, (3) prospectively examine the association between exposure to Web pages that contain sexual content and its effect on teens' sexual health-related knowledge, attitudes, beliefs, intentions, and behavior over a 16-month follow-up period, and (4) examine the effects of hypothesized moderators (ie, parental monitoring, parental communication about sex, sociodemographics, other media exposures, and exposure to sex-education programs on the association between exposure to sexual content on the Web and hypothesized mediators and outcomes. Teens will be asked to complete Web-administered interviews at baseline and at 4-, 8-, 12-, and 16-month follow-ups. Teens will also be asked to download and install Web-tracking software on their home computer, which will provide an objective measure of Web exposure to sexual content. Analyses will construct cross-sectional models to examine the relationship between teens' use of Web pages that contain sexually explicit, sexual health, and sexually related content, and their sexual health-related attitudes, beliefs, intentions, and behaviors at 16-month follow-up. Statistical analyses controlling for baseline assessments will prospectively examine the relationship between teens' use of Web pages that contain sexually explicit, sexual health, and sexually related content and adolescents' sexual health-related attitudes, beliefs, intentions, and behaviors.

    FOOTNOTES

    Accepted Apr 14, 2005.

    No conflict of interest declared.

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