Screen time is the amount of time spent using a device with a screen such as a smartphone, computer, television, or video game console. The concept is under significant research with related concepts in digital media use and mental health. Screen time use has increased over time leading to increased research in how screen time affects human health. Studies show that screen time directly impacts child development, and mental and physical health. The positive or negative health effects or screen time are influenced by levels and content of exposure. To prevent harmful exposure to screen time, some governments have placed regulations on its usage.
- 1 History
- 2 Physical health effects
- 3 Mental health effects
- 4 Limitations on Screen Time
- 5 References
The first electronic screen was the cathode ray tube (CRT), which was invented in 1897 and commercialized in 1922. CRT’s were the most popular choice for display screens until the rise of liquid crystal displays (LCDs) in the early 2000s. Screens are now an essential part of entertainment, advertising, and information technologies.
Since their popularization in 2007, smartphones have become ubiquitous in daily life. In 2015, 64% of all American adults reported owning a smartphone, including 85% of individuals between 18 and 29 years old. An American survey found a median of 3.7 minutes per hour of screen time over a 30 day period. Subjects 10 years and under averaged 0.7 minutes/hour more than the >10 year old range which equates to a 19% increase.
All forms of screens are most frequently used by younger age brackets, particularly young children. 98.5% of surveyed children aged 12–15 reported daily TV use and 91.1% reported daily computer use over a period of 30 days.
Race, Socioeconomic Class, and Screen TimeEdit
Research has shown that race and socioeconomic class are associated with overall screen time. Younger demographics and individuals who self-identified as Black and "Other" were associated with above average screen use. Additionally, Black and Latino Americans had longer screen times because of less access to desktop computers, which thus leads to more time on phones. In children, the divide is much larger. One average white children spend 8.5 hours a day with digital media, and Black and Latino children spend about 13 hours a day on screens. Black and Latino children are also more likely to have TVs in their rooms, which contributes to their increased use of screen time.
The discrepancy in the amount of screen time can also be attributed to a difference in income. In more affluent private schools, there has been a larger push to remove screens from education in order to limit the negative impacts that have been found from screen time. However, in public schools there is more push for the use of technology with some public schools advertising free iPads and laptops to students. Additionally, affluent families are able to afford nannies and extracurriculars that can limit the need for entertainment from screens.
Physical health effectsEdit
More screen-time has been linked with shorter sleep duration, decreased sleep efficiency, and longer sleep onset delay. When using any screen before bedtime, the blue light emitted disrupts the body’s natural melatonin hormone production. Melatonin is produced by the brain’s pineal gland and controls the body’s internal clock. This clock is what is referred to as the body’s circadian rhythm and it naturally is responsive to light. Melatonin levels increase as the sun sets and remain at that increased state for the remainder of the night. As the sun rises, melatonin levels start to drop. This hormone reduction is what helps the body’s natural rhythm wake up due to the bursts of natural sunlight. The light screens emit are in a similar spectrum of sunlight, but the blue light emission is what human circadian rhythms are most sensitive to. Studies have shown that the blue wavelengths are closely correlated to those from sunlight, which is what helps the body keep in sync with the sunrise and sunset. Therefore, using any screen prior to bedtime disrupts the body’s production of natural bedtime hormones which can trick your brain to believe it is still daytime making it harder to fall asleep.
As well as negatively impacting the adult sleep cycle, using screens can also affect one’s physical health. Obesity is a common result of spending great amounts on screens like a television, video games, or a computer screen. Studies have shown that if the amount of screen time adolescents spend was limited, the likelihood of obesity can be reduced. This sedentary behavior is largely due to the nature of most electronic activities. Sitting to watch television, playing computer games or scrolling on your phone takes time away from physical activities which leads to an increased risk of weight gain.
Increased use of screens in children has lead to an increase in sedentary activity because most screen usage occurs while sitting. TV and video games were once largest contributors to screen time, but the past decade has seen a shift towards smart phones and tablets. It has also been found that children who watch more than 2 hours of television a day are more likely to be overweight or obese. Additionally, one study showed that the increased use of video games and other forms of media consumption led to more back pain among Norwegian teens. It has been reported that screen time negatively affects health in children independently of their physical activity and eating habits.
One possible explanation for the link between TV and obesity is the amount of commercials for sugary and unhealthy foods. This advertising can have an effect on what gets purchased and consumed in a household. The effect of advertising was demonstrated in a study where children were shown cartoons with and without food commercials. The children who watched the food commercials along with the cartoons ate 45% more unhealthy snacks than the group who watched the cartoons without food ads.
Increased use of screens in children has also been shown to have a negative impact on the sleep of children. This correlation is because much of the time spent on screens for children is at night, which can cause them to go to sleep later in addition to the blue light from the screens making it more difficult to sleep. In teens, it was found that those who had spent more time on their screens were more likely to wake in the night from notifications on their phone, or experience disruptive sleep. In adolescents, the screen content impacts sleep as well. Content that stirs emotions has been linked with a delay in the onset of sleep.
Mental health effectsEdit
As previously discussed, sleep and screen time are heavily impacted by the other and can lead to affecting one’s behavior as well. If someone does not get an adequate amount of sleep, it can affect their behavior and performance for the day. High amounts of screen time also can significantly affect a person’s mental health. With screen usage increasing as time progresses, adults have begun spending more and more time focusing their attention of screens. This time spent sitting and viewing a screen has been linked to mental health effects such as anxiety and depression. Adults who spend six hours or greater using screen time are more likely to suffer from moderate to severe depression. This increased use in screen time has been shown to be directly correlated with an increased chance of depression in adults. With this added risk, lack of sleep plays a major role in a healthy mindset, but without proper rest, mental health can degrade at a higher risk.
An increase in screen time has been associated with negative cognitive outcomes for children between 0 and 4. A study on Korean children aged 24–30 months old found that toddlers with 3 hours of TV viewing per day were three times as likely to experience a language delay. Toddlers with higher TV time also scored lower on school readiness tests, which measured vocabulary, number knowledge, and classroom engagement. The same outcomes are not present in children older than 4. Children who watched more TV were found to have less brain connectivity between language, visual and cognitive control regions of the brain than their peers who watched less TV.
The American Academy of Pediatrics recommend for children in age 3 - 5, a screen time not longer than 1 hour per day. According to study published in November 2019, children who have a longer screen time, have slower brain development, what hurt "skills like imagery, mental control and self-regulation". The scientists add that: "This is important because the brain is developing the most rapidly in the first five years," "That's when brains are very plastic and soaking up everything, forming these strong connections that last for life." They also stated that screens changed childhood rapidly. The over exposure also hurts skills of litteracy, cognition and language.
Screen use has been implicated with a slew of behavioral effects, especially in children. The primary effect is an increase in sedentary activity. Approximately 47% of American children spend 2 or more hours per day on screen-based sedentary activities. This is in contrast with the 25.5% who reported at least 20 minutes of physical per day for a week. Additionally, the likelihood of a child participating in physical activity has been shown to decrease with increasing screen use. Screen use can also affect interpersonal skills. UCLA researchers reported that sixth-graders who went five days without screen use were significantly better at reading human emotions than sixth-graders with average screen use.
Academic performance can be improved by screen time depending on the length and content of exposure. Toddlers after the age of 18 months can be exposed to high-quality programming such as Sesame Street or PBS that provide educational television. The right content can prove beneficial, but too much screen time distracts students from studying. It is important for parents to establish a limit to how much screen time their children can use per day. Limiting and monitoring children's screen usage can increase cognitive development, but further research is required to get a better understanding of how screen time positively affects academic performance. On the other hand, increased screen use has been associated with missing school assignments. Students who used screens for more than two hours a day are twice as likely to not turn in homework on a regular basis. It is yet to be proven that screen time can significantly enhance academic performance, but it is known that increased use in screen time distracts students from focusing on class assignments.
Limitations on Screen TimeEdit
There is no consensus on the safe amount of screen time for adults. Ideally, adults should limit their screen time similar to children and only use screens for about two hours a day. However, many adults spend up to 11 hours a day looking at a screen. Adults many times work jobs that require viewing screens which lead to the high screen time usage. Adults obligated to view screens for a means of work may not be able to use screen time less than two hours, but there are other recommendations that help mitigate negative health effects. For example, breaking up continuous blocks of screen time usage by stretching, maintaining good posture, and intermittently focusing on a distant object for 20 seconds. Furthermore, to mitigate the behavioral effects, adults are encouraged not to eat in front of a screen to avoid habit formation and to keep track of their screen use every day. Specialists also recommend that adults analyze their daily screen time usage and replace some of the unnecessary usage with a physical activity or social event.
Screen time has been shown to affect children more than adults. Extensive screen time can have a lasting effect on children whose brains and bodies are still developing. The American Academy of Pediatrics breaks down limitations for children by age. They suggest that infants younger than 18 months should not be exposed to any screens (apart from video chats). Kids around 18–24 months old should furthermore be limited to high-quality media sources and supervised by adults while doing so. Once kids reach ages 2–5, the amount of screen time increases to up to an hour a day on any device total. There is no formal recommendation beyond the age of 5. The American Academy of Pediatrics emphasizes the role of parents in controlling screen time after the age of 5.
An ongoing study reported from the National Institutes of Health concluded that preteens who spent over 7 hours on screens a day and children who spend less than 7 hours a day had noticeably different development of their cerebral cortex. This part of the brain usually thins as people mature but the accelerated decrease could potentially be linked to amounts spent on screens. Long lasting effects like this should be considered when trying to implement limitations for children. Parents should be involved in monitoring their child’s screen usage and try to implement better and healthier practices by encouraging better bedtime routines, educating youth about the lasting effects, and limiting the amount of available screens in the environment.
Some countries have begun implementing regulations on screen time to protect their citizens. In Taiwan, there is a legal time limit on how much screen time kids can participate in. If the excessive screen use is found to have negatively affected a child's health, parents can be fined up to $1595. The new ban establishes time spent on screens as detrimental to health, and uses similar language to smoking and drinking regulations.
Other Asian countries have passed similar laws. In Korea, video game use among students has been implicated in many psychological and physical issues, like high rates of depression. Korea has established the Cool Down Program that makes video games automatically shut down after 2 hours of play, and can only be rebooted after 10 minutes of downtime. This is the second law enacted in Korea to limit gaming for students. The other law is called the “Shut Down Law” that bans gaming for children under the age of 16 between midnight and 6am.
China has enacted similar restrictions for users of the video game Honour of Kings. It had been regularly condemned by the government because of its addictive nature which is compounded by accessibility through a mobile app. To regulate the game, the government makes users create an account, which includes their age. Users under the age of 13 can only play for 1 hour per day, and those between the ages of 13 and 17 are limited to two hours per day. These policies attempt to limit screen time for children in response to research that reveals negative impacts of screens on children.
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