Years of mounting research has led to an unambiguous conclusion that televisions in children’s bedrooms are detrimental to healthy sleep [13–15]. Light-emitting diodes (LEDs) are found in most screens children encounter [16]. The light emitted by LEDs contains more blue wavelength light than typical incandescent light bulbs [16]. Blue wavelength light is found naturally in the morning hours and is important for regulating the circadian system [17]. This type of light cues the suprachiasmatic nucleus to suppress melatonin production, the hormone that promotes sleep [17]. As such, blue wavelength light in the evening hours is detrimental to sleep. Accordingly, research has found that prolonged exposure to screens prior to bedtime is associated with poorer sleep patterns [18]. Practically, children who play electronic games in their rooms past their bedtimes sleep less than their peers [19]. Of the sleep they do get, these children experience poorer quality and feel more tired after awakening than peers who attain sufficient sleep [20]. Children who play electronic games or who use the computer for nonacademic purposes for more than 2 hours have higher odds of attaining insufficient sleep [21].

With regard to gaming in particular, various models have been proposed to explain how gaming may displace sleep. One model argues for a displacement effect, whereby the more time children spend on games, the less they tend to sleep [17]. Another theorizes that the excitement of game play arouses children physiologically, making subsequent sleep difficult to initiate [17], although evidence that physiological arousal detracts from sleep onset has not been found [22]. Prolonged gaming, however, does reduce total sleep time. One study assigned one group of adolescents to play fast-paced, violent video games for 50 minutes. A second group played for 150 minutes [22]. While the adolescents who played for the longer time period lost, on average, close to half an hour of sleep, measures of physiological arousal did not detect differences between them and the more moderate players [22]. All participants still fell asleep within 30 minutes, a clinically acceptable sleep latency [22]. While slow wave sleep was significantly affected in the longer gaming group, the difference was small [22]. No other changes in sleep architecture, the structure and pattern of sleep along a number of variables, were observed [22]. After stopping, researchers also asked participants if they would like to continue playing, and if so, for how long [22]. On average, adolescents who played for the longer time period still wanted to play for another quarter hour [22]. Among both groups, participants who wanted to play for longer took longer to fall asleep than those who wanted less additional time [22]. Study authors hypothesize that continued cognitive involvement in the game may create a desire to continue playing, thereby inhibiting sleep onset [22].

Common sense would suggest that the more time children spend on screens, the less they spend in physical activity. Interestingly, recent evidence shows only a small negative relationship between video game use and children’s physical activity [3]. One large meta-analysis of previous studies could not find sufficient evidence in support of the theory that video game usage displaces physical activity [23]. Out of all these studies, only one used a randomized design where games were removed from the home and any resulting changes in physical activity were monitored [3]. This study found a statistically significant but clinically negligible increase in daily amount of physical activity once all games were removed from the home [24]. The physical activity of children who had games removed increased by only 3.8 minutes per day [24]. No increase in weekly physical activity was found [24]. The lack of displacement can be understood in conjunction with related findings. Children who spend a great deal of time on video games can also spend sufficient time in physical activity, and children who do not play video games can also refrain from physical activity if their activity preferences are sedentary (e.g., reading, music, art) [25, 26].

The emergence of active-input electronic games—games requiring players to move their bodies to continue and influence game play—has added a new element to the research on electronic games and physical activity. Active-input games have been shown to increase light-to-moderate-intensity physical activity in the short term (i.e., the activity observed in the laboratory while the children are playing) [3]. However, research so far indicates that active-input games are not effective for maintaining an increase in physical activity over time [3]. The few studies that measured physical activity during active-input game play over longer periods of time found that children gradually became less and less interested in playing these games over time [3]. As such, active-input games may be best recommended only insofar as they can engage currently inactive children in some physical activity. Once children are sufficiently engaged, other forms of physical activity should be encouraged. Continuing active-input games as the sole method for activity is unlikely to be helpful [3].

There is a distinction between sedentary behavior and not engaging in activity vigorous enough to meet the criteria for moderate-to-vigorous physical activity [3]. When a child engages in activities in which he remains relatively still—such as when playing traditional video games, watching television, and reading—he is said to be sedentary. A child who is engaged in moderate-to-vigorous physical activity might be playing soccer or swimming. Between these two extremes, a child might be engaged in light activities that are neither sedentary nor vigorous enough to count as “physical activity,” such as walking to school, cleaning her room, or playing a board game. This distinction explains how children who play video games can engage in physical activity while also having higher rates of sedentary behavior than their nongaming peers [3]. Playing traditional (i.e., not active-input) video games is an example of sedentary behavior [3]. Prolonged epochs of sedentary behavior are associated with a host of negative health outcomes [3]. Because children who play games can also be physically active, the conclusion cannot be drawn that all video games present excessive sedentary behavior [3]. However, children who play for long stretches at a time should be encouraged to take breaks to reduce the negative influence of sedentary behaviors [3].

Because obesity is related to physical activity and sedentary behaviors, it has been studied with regard to video games [3]. Overall, research in this area is mixed. Some studies find effects on cardiometabolic health based on game play, and others find no such association [3]. While causality has not been established, the amount of time children spend on video games is associated with increased risk of obesity [27]. One study randomly assigned some 4–7-year olds to have their TV and computer time cut in half, while others continued to play as they had been [28]. After 3 years, the group with halved screen time showed a significant reduction in their body mass index (a weight-to-height ratio commonly used as an indicator of healthy weight) [28]. Children who were not assigned to receive a reduction in screen time displayed no such BMI reduction [28]. Taken with the findings that excessive sedentary behavior negatively affects health, results continue to suggest the positive outcomes of limiting video game usage without necessarily advocating for complete elimination [3].

Psychosocial development refers to the development of personality, and it encompasses the psychological and social attitudes and skills children acquire as they age and mature. Parent–child interactions are typically among the first rich opportunities for infants and young children to begin learning about normal face-to-face interactions. Screen time takes away from the time that children would otherwise interact with parents [29]. Before addressing children’s screen time among a number of psychosocial aspects, we briefly mention parents’ screen time. Parents’ use of screens also detracts from parent–child interactions [30]. In particular, being occupied with their own screens inhibits parents from monitoring and interacting with their children [30].

Part of normative social interactions is tolerating brief periods of non-stimulation, as may occur while waiting for the server at a restaurant, riding in a car, or accompanying parents on errands [29]. Parents are commonly observed to use screens to keep young children occupied during these times. The electronic device industry has termed this usage of their product as a “shut-up toy” [29]. Physicians and researchers are becoming concerned that this practice seriously impedes children from learning the internal mechanisms needed to occupy themselves for initially short and then gradually longer periods of time [30]. Anecdotally, parents’ defense of using screens in this fashion typically includes some comment that their child “cannot” be quiet without it. Rather than argue with the truth of this statement, we acknowledge that children cannot do most psychosocial tasks until they learn to do so. Learning comes out of a necessity. If children never need to occupy themselves because the screen supplants the need, they are not expected to learn this skill in the long term [29]. Precisely because children “cannot” occupy themselves without screens justifies that screens should not be used in this manner.

Use of screens to access social media is extremely common among adolescents, who use the Internet for social interaction more than any other age group [31]. Before the proliferation of social media sites and applications used for connecting with people already in the adolescent’s social circle, researchers and parents alike were concerned that Internet usage would cause adolescents to become withdrawn, socially isolated, and forge superficial connections with strangers [31]. Longitudinal studies bore out these concerns, with evidence that Internet usage was associated with social withdrawal among adolescents after less than one year [32].

This is in contrast to current usage studies, which show that adolescents now use the Internet primarily to maintain preexisting friendships [31]. Research to date suggests that forging social connections on the Internet may have differential effects on adolescents depending on a few factors: type of technology, gender, and social anxiety [31]. The Internet can facilitate social interactions when adolescents talk with preexisting friends or use instant messaging [33, 34].

Gender moderates outcomes as well. While the personal self-disclosure needed to form strong friendships is challenging for many early- and middle-adolescents, boys struggle more than girls to disclose in face-to-face communication [35]. Computer-mediated communication (CMC) eliminates almost all visual inputs and outputs [36]. CMC also provides time to prepare comments in advance and manage the timing of responses [36]. As hypothesized, CMC is effective at encouraging a higher rate of self-disclosures and more intimate self-disclosures [37]. Consequently, boys generally benefit from CMC more than girls [36].

Social anxiety influences how adolescents use the Internet and are affected by its usage. Researchers debate two approaches to this notion: the rich-get-richer hypothesis and the social compensation hypothesis [31]. Rich-get-richer presumes that adolescents who are already socially savvy simply translate those skills online and become socially competent on the Internet as well. By contrast, the social compensation theory proposes that adolescents who are socially unskilled are drawn to the Internet because of the lower stakes of online interaction [31]. Most research results provide support for the rich-get-richer theory [31]. However, adolescents who are socially anxious do prefer online disclosure over in-person disclosure [36]. As such, it is theorized that socially anxious adolescents can benefit from online communication with their preexisting friends to the extent that it allows them to deepen their relationships [31]. At this stage, it appears that Internet use likely does not teach social skills. It may, however, provide another outlet for already socially deft adolescents to engage socially and a more comfortable outlet for socially anxious or male adolescents to deepen preexisting friendships.

Excessive screen time also raises concerns about mood and anxiety. Video game play has been associated with higher levels of anxiety and depression [38]. Children who play for more than 30 min per day are more likely to feel negatively when they wake the next day [39]. There may be gender differences on games’ impact on mood. One study found that girls reported increased stress in response to violent game play, whereas boys did not [40]. Researchers, clinicians, and parents voice concerns that some adolescents feel more negatively about themselves when they compare their social lives to those of their peers on social media [41]. Despite these concerns, there does not seem to be sufficient evidence to warrant recommending avoidance of social media to prevent or mitigate depression [41]. Issues regarding mood are challenging to study given their multiple influences and multiple screen modalities. Current research continues to recommend considering children and adolescents’ mood and screen usage on an individual basis.

Of all the video game research of the past 10 years, the most conclusive results were found in the area of violent video games and aggression [7]. Over one hundred research articles examining the relationship between violent video games and aggression were culled into a meta-analysis [42]. This analysis found that violent video games had a significant effect on the 6 aggression-related outcomes studied: aggressive behavior, aggressive cognition, aggressive affect, physiological arousal, empathy, and prosocial behavior [42]. Other meta-analyses have found an association between violent video game playing and aggressive behaviors [43, 44].

A challenge to assessing aggression as a result of violent video game play is that these studies often measure observable behaviors occurring just after game play in the laboratory. Yet very few parents have such a narrow concern—when people speak of aggression and violent video games, they refer to long-term outcomes or changes in children’s brains as a result of playing. Consequently, researchers have begun using brain imaging technology to investigate underlying neuronal differences between players of violent games and nonviolent games. Specifically, researchers have hypothesized that extended exposure to violent game play causes a suppression of activity in the emotion-processing centers of players’ brains [45]. One study compared violent game players to nonviolent ones and found no difference in suppression of emotion-processing centers of the brain [46]. Another fMRI study scanned the brains of 13 adolescents who were high consumers of either violent or nonviolent video games to examine how the emotion-processing centers of their brains responded to playing violent games. During violent video game play, researchers found increased activity in emotion-processing centers among players who did not regularly play violent games and reduced activity in players whose game of choice was typically violent in nature [45]. While the transference of neuroimaging studies to observable changes in behavior or mood is still tenuous, the authors hypothesize that these findings suggest a possible “desensitization” among regular players of violent video games [45]. Due to logistical challenges and financial constraints, most brain imaging studies in this area have enrolled only a small number of participants, so conclusions are limited.

The most vocal critic of violent video game research discovered many fewer connections between aggression and violent video game play in his own studies than are found in the field at large [47]. This researcher contends that the studies that found an association between aggression and violent video games report only negligible effect sizes [48]. In response, some researchers acknowledge a small effect size, but point out that children and adolescents play these games a great deal [7]. They argue that the effect sizes compound over time as game play continues, so that the association accumulates into a more meaningful difference over time [7]. Others do not agree that the reported effect size of the association between aggression and violent video game play is small—they point out that they are similar to the effects of secondhand smoke on lung cancer [7, 49].

The same critic referred to has also posited researcher bias as contributing to the evidence that violent games are associated with aggression [7, 48]. This claim was investigated using statistical tools to look for bias due to the following: a prominent scholar who influences others, a group of researchers who have formed a consensus, or a systemic bias that excludes findings that do not support the hypothesis that video games are associated with aggression [50]. This study found no evidence to support the presence of any of the three biases [50]. Even the most vocal critic of violent game research has found some results that violent games are connected with increased aggressive thoughts, increased physiological arousal, and decreased prosocial behavior [48, 50]. Despite ongoing debate within the research community about bias, study design, statistical methodology, and effect sizes, the literature increasingly supports the conclusion that violent video games cause more aggression in players than nonviolent ones [50].

A limited number of television shows, such as Sesame Street and Blue’s Clues, have been studied extensively and found to promote academic skills in preschool children [29]. In contrast, television shows with fast pacing and quick editing cuts have a deleterious effect on attention among child viewers [51]. Even taking into account shows with educational content and slow pacing, children younger than 30 months require real-life interactions for learning [52]. Therefore, even passive content that bills itself as “educational” cannot confer a benefit to very young children. With the proliferation of smart phones and downloadable applications (“apps”), many parents have come to believe that interactive games can help their very young children learn. Complicating matters, thousands of phone apps are marketed as “educational” without any research to support this claim [29]. So far, only one study has shown that children can learn some language skills from an interactive game at 2 years of age [53]. Outside of this study, there is no other research to support the use of interactive games with toddlers [29]. Some parents argue that their children must learn to use the devices at a young age so that they are not disadvantaged when they are older [54]. These parents can be reassured that even apes, such as Rhesus monkeys and Orangutans, can easily learn to use screen-based devices [55, 56]. Electronic books have been found to engage children with some dynamic characteristics such as narration, text highlighting, animation, sound effects, and games [53]. However, the very features that engaged the children simultaneously impaired their comprehension of the story [53]. This evidence suggests that while electronic books may not be harmful, they are not as beneficial as noninteractive, i.e., traditional, books.