Children and Screens

Executive Summary

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Digital media — laptop computers, iPads, iPods, and smartphones as well as other current and future electronic devices — are and will continue to be our children’s constant companions.  “The times, they’ve been a changin’.”  Just a few years ago, children generally accessed words, images, sounds, and ideas (‘content’) in settings, or through channels, that adults could easily control.  However, this is no longer so.  Children now grow up with portable, relatively low-cost, ‘personal’ devices that can and do go far from parental supervision.  The extraordinary capabilities of such devices give young users practically unlimited access to a vast variety of content, often without adult knowledge or supervision. Indeed, babies who 9 months of age
or younger may spend much of their waking hours in new digitally-mediated environments whose effects are currently largely unknown.


The Sackler Colloquium on “Digital Media and Developing Minds,” held at the Beckman Conference Center in Irvine, California, on October 13 through 16, 2015, provided scientific experts from a variety of complementary intellectual disciplines with a rare opportunity to compare, contrast, and combine their technical knowledge about topics of shared interest.  These exchanges served to establish and consolidate an important foundation of pooled knowledge about emerging technology, child development, and digital media, setting the stage for ground-breaking future collaborations in several key relevant areas.

Early Childhood, Family and Parenting

Babies are born with a lifetime supply of brain cells. The formation of synaptic connections between them, in response to myriads of stimuli, largely accounts for the brain’s physical growth during early childhood.  In this context, we know a great deal about the adverse effects of under-stimulation on brain development.  Yet relatively little is known about: (i) the effects of over-stimulation on young brains; (ii) the impact of adults’ media-related behaviors on children too young to comprehend the media to which they’re exposed; and (iii) the specific effects of pervasive, immersive, increasingly realistic types of media that define young children’s environments today.Young children’s developing minds and brains likely cannot decode meanings of word and image sequences very well until at least the age of 2 years or older.  Although children in the past received their first exposures to screen media (via television) at around the age of 4 years, while media companies ignored infants and toddlers, now children as young as 4-6 months old are exposed to substantial amounts of television and other screen media.  Some of this content is intended for them, but much of it is targeted at adults in environments where children just happen to be present.  As a result, there may be mismatches between the media stimuli to which adults are exposing children and the children’s capacity to process what they’re seeing and hearing.

Children’s media experiences also are being defined by the extent to which the adults with whom they spend time are mentally and emotionally occupied by their digital devices.  Such preoccupations have implications for the gap between what children need to receive from engaged adults (for healthy intellectual and emotional development) and what they are actually getting.

Young children have difficulty applying on-screen learning to off-screen tasks.  Adding a social dimension to their screen-based learning may mitigate this “screen deficit”.  We must learn much more, though, about what combinations of task type, screen type, and social interaction work best for children at each stage of mental and physical development.

At home and in organized child-care settings, children’s exposure to digital media (including advertising and marketing content aimed at them) is increasing.  So-called “educational” apps for young children are typically unlike the highly controlled content used in academic settings to determine what children can learn and imitate. This commercialization gap – between the lab and the marketplace – illustrates a difficulty facing parents, clinicians, educators, and policy makers.  Guidelines that encourage the use of “developmentally appropriate” media are not helpful without a shared, valid understanding of what is developmentally appropriate.


Today’s children are sleeping 2 hours less each night than their counterparts of a century ago.  There is substantial evidence for a systematic association between increased digital-media usage and decreased sleep duration as well as increased prevalence of sleep disorders.

The deleterious effect of increasing media usage on sleep duration may be mediated by excessive exposure to light from digital screens.  Screen light suppresses release of the sleep-promoting hormone melatonin, shifts the daily circadian rhythm by about ninety minutes, makes it more difficult to fall asleep, and leads people to wake up in a more fatigued state.  Beyond direct effects on sleep duration, there are questions about the relationship between screen usage and the body’s ability to accomplish necessary processes (e.g., memory formation and removal of toxic metabolic debris from the brain) that accompany sleep.  Nighttime screen use can also inhibit sleep through increased vigilance.


Screen time is one of the best-documented causes of obesity in children, and obesity is one of the best-documented effects of childhood screen time.  Randomized controlled trials of reducing screen time in community settings have led to reduced weight gain in children, demonstrating a cause-and-effect relationship.

Current evidence suggests that exposure to screen media causes obesity in children and adolescents primarily through reduced sleep duration, increased eating while viewing, and greater exposure to marketing of high-calorie, low-nutrient food and beverages that change children’s preferences, purchase requests, and consumption habits.

Some evidence also offers promise for using interactive media to help improve children’s eating behaviors, increase physical activity, and prevent or reduce obesity. Future interdisciplinary research is needed for examining the effects of exposure to newer mobile and other digital media on obesity

Violent and Sexual Media Content

Numerous research methods have shown that exposure to both active and passive forms of violent media content increases children’s aggressive thoughts, feelings, and behaviors.

Brain-imaging studies confirm that specific physiological arousal effects persist after game play ends.  Playing violent video games stimulates the brain’s threat response system, inhibits the regulatory role of the prefrontal cortex, and increases visuo-spatial attention and mental processing speed.  The net effect of these changes is to heighten the gamer’s capacity for action while inhibiting his or her capacity for reflection.  Repeated exposure to media violence ‘desensitizes’ people, reducing normal negative emotional arousal to actual violence in the real world.

Results from many studies indicate that children exposed to more sex on TV and in movies are more likely to initiate sexual intercourse and to have first intercourse at a younger age.  Also, there is good evidence that exposure to violent sexual content increases the likelihood of sexual aggression. Whether such phenomena generalize to effects of sexual content that is experienced online or through other digital media remains to be fully determined.  The wide variety of digital sexual content that children are accessing, and even generating, complicates research in this area.

Research studies using different definitions of sexual content and behavior are producing widely divergent results.  However, emerging evidence suggests that children who “sext” are more likely to engage in other risky sexual behavior.  Although the current US teen pregnancy rate is lower than it has been during past decades, it still remains the highest in the developed Western world.  In this context, digital media constitute a potential tool for promoting birth control.


Like social media access, transient encounters with peer aggression and social cruelty are extremely common.  When these encounters are severe or repeated, they can have profound psychological impacts, and are associated with resulting academic difficulties, problematic peer relationships, anxiety, depression, and even suicide.

The impact of digital peer aggression is mediated by gender, sexuality, and substance abuse.  Females are more likely to report cyberbullying victimization.  Substance abuse is associated with perpetrating cyberbullying, and LGBT youth appear to be at elevated risk of becoming online targets.

The study of cyberbullying has been impaired significantly by the lack of an agreed upon, operational definition of this phenomenon.  The traditional “bullying” rubric35102623_l is not always used to assess cyberbullying.  Also, we are still unsure how well “bullying” predicts traumatic victimization online in the way that it predicts such victimization in person.  Furthermore, cyberbullying is often confused with other digital behaviors, such as digital conflict.  Therefore, more basic work is needed on the taxonomy of different digital antisocial behaviors.  That work will make it possible to reconcile seemingly conflicting empirical findings in this area.  

Certain types of bullying may only be possible in digital environments.  For example, self-cyberbullying is a phenomenon in which users create fictional personae through which they bully themselves online.  They then bring evidence of their victimization to others (primarily peers) in a bid for sympathy and attention.  Other types of bullying that may only be possible in a digital environment might include identity theft and online impersonation, along with extremely broad fast distribution of content such as rumors and personal videos.

How online experiences of peer aggression differ from the offline versions remains to be determined.  We do not yet know for sure what can be reasonably expected (developmentally speaking) from children’s interactions in their digital environments.

Personal Privacy

Computers, tablets, smartphones, and wearable digital devices do more than just deliver content to children.  They also gather and distribute information about children, mostly without any adult’s permission.  This intimate relationship among media, devices, and children makes the current state of child privacy both surprising and problematic.
Internet-privacy research has focused principally on what young adults choose to post online, and how they perceive their privacy risks.  Little work has been done on how overt and covert data-gathering mechanisms (including, for example, data mining and user tracking) interact with the developmental processes of childhood and adolescence.

Online parental behavior also has important privacy implications for children.  Parents are posting their children’s pictures, stories, and other traditionally private information from birth onward.  This is creating digital footprints for kids long before they have a chance to consent or object. A gap exists regarding teens and privacy.  This is reflected in the relative lack of research about online teen privacy, and in the fact that the Children’s Online Privacy Protection Act applies only to children younger than 13 years old.

Advertising and Marketing

Advertising and marketing influence children and adolescents in numerous powerful ways.  Advertising affects children’s diets, interactions with caregivers, attitudes about the world, self-image, and decisions to engage in deleterious health behaviors (e.g., alcohol and nicotine consumption).

Children’s exposure to advertising on traditional screen media is still of significant concern.  Moreover, children and adolescents increasingly are being exposed to media through mobile devices, in varied formats (e.g., apps, social media, and games), that are potential delivery systems for youth-oriented advertising through which marketers have opportunities to mine personal data.

When looking at new media environments, we do not yet know how much persuasive content is reaching children, whether they are aware of the intentions of its producers and distributors, nor whether such awareness could have protective effects.

The more we understand about the effects of advertising and marketing in both new and traditional media, the better we can assess their potential to promote healthy behaviors and protect youth against the adverse effects of unhealthy messages.

Media Multitasking

Simultaneous use of multiple media streams is associated with cognitive changes that even effect subsequent performance of single tasks.

On the one hand, habitual multitaskers demonstrate reduced ability to filter out irrelevant information in their environment or in recent memory, poorer focus on task goals, and less sustained attention.  On the other hand, they perform better on tasks that require the integration of multi-sensory input.

One study also indicates that, compared to other populations, heavy media multitaskers have less gray matter in the frontal component of the default mode network, and less within-network resting-state connectivity.

Causality is an open question.  We do not yet know if media multitasking changes the brain and behavior, or if people predisposed to attentional differences are more inclined to multitask.  We also have an incomplete understanding of how, or even whether, media multitasking differs from other kinds of multitasking behaviors. Imaging studies are shedding light on the mechanisms through which multitasking operates. Ongoing research is revealing the extent to which smartphones are distracting students, triggering various psychological and neurophysiological responses, and adversely affecting their academic performance.

21191582_lDigital Learning

The educational institutions of the last century were created to address a scarcity of information.  They emphasized orderly teaching and learning, along with a rigid schedule of standardized evaluation that measured where each child’s academic journey ended regardless of where it began.  In contrast, today’s children grow up with much easier access to information.  This primes them for informal, demand-driven, networked learning in more fluid, social, peer-based environments.

At the same time schools today have to teach more material, and more complex skills than ever before. These rising expectations, along with perceived advantages of digital tools – such as greater engagement, educational effectiveness and cost effectiveness, convenience and access to educational materials – are fueling broad interest in digital media technologies.

Compelling research evidence is only beginning to emerge that can affirm these perceived advantages. Where technology has its most positive effects, teachers also play a crucial role, engaging in instruction and support.

However, benefits of shifting to greater use of screens must be weighed against the potential disadvantages. For example,readers of electronic textbooks may do more multitasking than when using print-counterparts, and be more susceptible to distraction.  Research indicates that students concentrate best when reading print, and that most prefer reading long passages from printed books rather than from digital screens.

A further concern is that the proliferation of digital media tools may be exacerbating inequity. Children with substantial economic resources and parental support are acquiring what one speaker described as “superpowers”, while those with fewer resources and less adult support are at greater risk of unproductive uses of technology.

Nevertheless, adopting technologies in ways that are mindful to these concerns could lead to substantial benefits by making personalized education scalable, providing more equitable access to educational opportunities beyond the classroom, and facilitating students’ involvement with shared-interest groups.  The role of digital media in managing this process ultimately may be more valuable than its direct use for instruction.

Virtual Reality

Virtual reality (VR) uses tracked physical movement, combined with visual and haptic feedback based on that movement, to make a user feel present in a digitally rendered environment.  This sense of presence enables VR users to have intense experiences that otherwise would be physically impossible, unduly dangerous, counterproductive, or prohibitively expensive.

Laboratory experimental trials have demonstrated VR’s capacity to help people experience others’ lives and circumstances.  This suggests an important opportunity to cultivate empathy and promote equity.

Specialized VR technology in labs at universities and major corporations is currently being migrated to the world’s living rooms.  Ultimate consequences of this next leap in digital content delivery are unknown.  To date, only eighteen studies (with just 400-500 total subjects) have put VR viewers on children.  Only two of these studies have focused on anything other than clinical applications and responses to pain. More research must be conducted to obtain important information about how VR experiences affect children
in the real world.

Differential Susceptibility

Technological advances have made pervasive, immersive, interactive, and highly personalized media the new norm.  Consequently, it has become less and less useful to speak in terms of media, overall, affecting children as an undifferentiated group.  Individual differences among children and adolescents in susceptibility to digital-media exposure should receive much greater research consideration.

Mass personalization in media requires similarly personalized approaches to media-effects research. We must ask how particular kinds of content, experienced through discrete distribution channels under various environmental conditions, affect children through mechanisms specific to their personal characteristics (e.g., age, gender, ethnicity, genetics, epigenetics, socioeconomic status, physical and psychological condition, family structure, educational opportunities, and prior experience).  Disregard of such differential susceptibility may explain why past studies have yielded conflicting conclusions, because some subgroups may experience much larger media-exposure effects than others do.

Research Methodologies

We must move beyond studies designed around the traditional behavioral patterns, simplifying assumptions, and investigative methods of the television era.  For example, given the persistent, pervasive, and immersive character of modern digital media, much more emphasis should be placed on understanding what makes a healthy media diet.

Children’s individual characteristics may make them differentially susceptible to certain media effects.  Answering questions about such differential susceptibility, obtaining the factual basis for effective interventions, and formulating credible media-use guidelines will require different methods than used in traditional past media-effects research.

Innovations in study design (e.g., more large-scale, randomized, controlled, longitudinal, and naturalistic studies), complementary quantitative and qualitative data collection, and improved data analytics will be required.  Modern data-collection and analysis methods will enable make more naturalistic research.  

The media-effects research community hopes to move beyond identifying associations to identifying systematic causes and effects through deploying its powerful new research tools.  These include improved brain-imaging techniques (functional magnetic-resonance imaging [fMRI]; magnetoencephelography [MEG]; and functional near-infrared [fNIRS] optical imaging); portable electronic language processing devices that provide continuous, real-time data on participants’ media exposure; and trained peer- and near-peer interviewers who can elicit candid responses (while eliminating self-reporting errors) from young study subjects. New, more precise, shared standards for characterizing media content and measuring media exposure effects will facilitate aggregating data from diverse sources and different disciplines.  Enhanced data sharing will be critical for understanding the multidimensional effects of digital media on human cognition, brain, and behavior.


Targeted interventions concerning digital-media exposure and effects are possible. Early childhood, adolescence, and young adulthood each include identifiable periods of dramatic neuroanatomical and cognitive change (development of self-regulation, executive mental functions, working memory, and cognitive flexibility). These developmental periods are both times of vulnerability to particular modes of media exposure and particular types of content, and times of opportunity for targeted interventions. Progress in exploiting these opportunities has been hindered by the lack of interventional studies, most of which have focused on elementary school children.  More theory-based intervention research is needed. Some experts advocate a pragmatic approach to intervention research, arguing that  a combination of common sense, common knowledge, persuasive speculation, and trial-and-error can lead us to practical advances even if the theoretical enterprise lags behind.  At the Sackler Colloquium on Digital Media and Developing Minds, however, more voices were heard for favoring greater reliance on theory-based research.  According to them, it offers the best hope for efficient progress toward effective interventions regarding effects caused by exposure to the tsunami of digital media.

Social Transformation

In the US, almost 90% of teens 13-17 have desktop or laptop computer access.  Almost three-quarters of them have smartphones. Despite this high degree of market penetration, more granular analysis shows that there are important differences  in media behavior associated with gender, race, and ethnicity. These considerations also highlight important equity issues relevant to regulating children’s media exposure.

Despite ample availability of digital media for accessing and distributing information, young people see society as being more about surveillance and control than about expression.  This perception shapes their willingness to voice political opinions, and raises questions about the future of politics.

Changing patterns of social interaction suggest that today’s youth are less empathetic than their predecessors.  Declining reliance on face-to-face conversation, and increasing reliance on electronically mediated interactions, may perhaps both reflect this social shift and be contributing to it.  Furthermore, notions of empathy, intimacy, and norms for adult emotional capabilities may be evolving in ways not yet understood.  Whatever the ultimate truth about these crucial open matters, the topic of empathy in the digital age should be a high research priority. We do not yet know much about where, when, how, and for whom digital media support positive social connections and well-being.  This ignorance reflects a gap in research regarding the positive effects of digital media in general and interactive media in particular.

Multi-Faceted Policy Concerns

Researchers capable of advancing this field will need more funding opportunities and institutional support for multidisciplinary collaboration.  

Substantial financial support for research on digital media and developing minds will have to come from nimble, responsive, and generous funders, because the rapid pace of technological, cultural and behavioral changes make long time lags between grant proposals and publication highly undesirable.

Some investigators have argued that it would be easier to obtain more ample and timely funding for sophisticated scientific studies of digital-media effects if the National Institutes of Health were to establish a Media-Effects Study Section.  It would provide a forum for applying more directly relevant expertise to the review of grant proposals in this field.  However, other investigators have cautioned that specialized study sections can be a two-edged swords with both pro and con outcomes. While academics and policy makers debate definitional issues, millions of children and young adults are enduring media-related behavioral problems. Media-effects research is being adversely impeded by controversies over small differences of opinion that obscure important areas of substantial agreement.  All interested constituencies must distinguish between consequential and inconsequential differences.  They must act upon their shared understanding of who is being hurt by digital media and how those at risk can be helped. Considering the challenges that children face in negotiating an ever changing and often confusing persuasion environment, increased pressure should be applied to marketers for ensuring that their practices are developmentally appropriate and transparent (e.g., alcohol and e-cigarette advertising). Schools, nonprofit organizations, and other institutions should develop media education and digital-literacy programs for helping youth navigate today’s complex commercial culture without diminishing their basic right to privacy. An analysis must be conducted about the efficacy of the Children’s Online Privacy Protection Act (COPPA) in order better to understand what personal information is being collected, used, and disclosed about children without parental knowledge. The large-scale policies of Korea and China should be taken as useful examples (and counterexamples) of how to address Internet-addiction epidemics from a public health perspective. While we await the discovery of biomarkers for media-related addictions, diagnosis will continue to depend on the effective use of symptom lists and interview tools.  Both require further refinement. Three-quarters of all fatal vehicle crashes involve some type of distraction.  The incredible functionality of mobile media devices, combined with social norms and mental effects of electronic communications, have introduced major new sources of driver distraction.  At least some mobile-media users are susceptible to increased impulsivity, sensation seeking, and reduced working-memory capacity.  In this context, the suboptimal patchwork of state regulations on drivers’ mobile-media use requires reconsideration and great strengthening. States have encountered constitutional obstacles in their efforts to limit children’s access to harmful media content.  The US Supreme Court has permitted such regulation with respect to sexual material, but state efforts to keep violent content away from children have failed to overcome the Court’s dubiously strict scrutiny.


In broad summary, there is now enough sound basic knowledge to pose truly ambitious important, fundamental research questions about how digital media affect children’s mental and physical development and well-being.  For example, we are ready to ask: “What is the quantity, quality, and character of media content reaching children today?  Which informational attributes account for different children’s responses to different digital media?  What are the consequences of pervasive, immersive media exposure for children’s bodies, minds, and social experiences?  How do children and adolescents’ mental processes and brain mechanisms change for good or ill because of the digital media to which they are exposed?  May new evolving policies be formulated and implemented to adaptively and beneficially guide all of this?”  

The Sackler Colloquium on Digital Media and Developing Minds has helped participants to transcend their disciplinary philosophical differences and respective institutional agendas.  More importantly, it has reminded all of us that we are united by a common desire to make a better world for children.  That shared commitment will inspire many productive scientific and practical collaborations in the years ahead.