Figure 2. Screen-related factors contributing to hyperarousal or fight-or-flight
Intense Sensory Stimulation
Screen brightness, quick movements, and supersaturated colors all contribute to visual sensory overload.8 Intense stimulation heightens attention and arousal, feeding into fight-or-flight.9 Furthermore, excessive stimulation can overwhelm the sensory system, causing other parts of the brain to shut down in order to compensate. Afterward, the brain experiences a relative sensory deprivation, which can feel uncomfortable and lead to irritability. Some individuals may even suffer light- or screen-associated seizures, tics, and migraines when intense visual stimulation produces electrical excitability, or the overfiring of brain networks.10 In Japan in 1997, over seven hundred people, mainly children, experienced seizures and vomiting after watching a particular Pokémon cartoon episode that utilized flashing colored lights in a scene depicting two characters in battle.11 The vast majority of victims had never had a seizure before. While extreme, this example shows how intimate the relationship is between the eyes and the brain. We should view the visual effects from electronic screen interaction as a spectrum, with seizures, tics, and migraines representing the more severe or tangible manifestations on one end, and everyday “irritation” and general nervous system dysfunction on the other.
Another sensory-related reaction to extended screen-time is the game transfer phenomenon, where users experience visual hallucinations of game-related objects, like an imprint, after prolonged play.12 Lastly, from a development perspective, repeated exposure to intense sensory stimuli leads to an overactive visual system; the child will attempt to pay attention to everything around him or her, making it difficult to focus and causing other sensory integration issues.13
Psychologically Engaging Content or Activity
Though not all screen activities are games, those that are add another layer to the fight-or-flight story. As the need to win or improve is repeatedly reinforced in some way during play (by earning rewards, escaping from threats, being promoted to the next level, and so on), the player becomes more and more hyperaroused. Meanwhile, the feel-good brain chemical dopamine is continually being released, causing the player to want to continue playing — often for longer than planned. The more engaging a game is, the more it increases dopamine-related attention and arousal, which reinforces itself over time and makes it harder to stop playing. Game designers are absolute geniuses at creating the timing and intensity of in-game rewards.14
In terms of content — for both video game and Internet use — violent, competitive, sexual, vivid, interesting, challenging, and bizarre images and situations all increase arousal or fight-or-flight reactions.15 In terms of game type, role-playing games, such as multimember online role-playing games (MMORPGs), are known to be particularly addicting.16 In part, they may be compelling because they play off of adolescent developmental needs, such as identity formation.17 With younger children, the game Minecraft, which consists of building structures, items, and weapons out of various materials in the form of blocks — activities that seem relatively benign on the surface — is frequently described as “mesmerizing” by parents as their children become “obsessed” with it.18
Disruption of the Body Clock
Both natural and artificial light relay information to the brain and impact the body’s biorhythms, including the sleep-wake cycle, a “circadian rhythm,” and hormone cycles, which have daily, monthly, and seasonal variations.19 As mentioned, when the brain is exposed to the unnaturally bright light of electronic screens, the sleep signal hormone melatonin is suppressed, and natural biorhythms are disrupted.20 Additionally, light from screens tends to be rich in blue tones, which is particularly disruptive because blue light mimics daylight. Low melatonin is linked to depression and inflammatory states — such as cancer and autism — as well as alterations in hormone function, including reproductive hormones.21 Aside from melatonin suppression, light-at-night is associated with other hormonal abnormalities, such as low growth hormone.22 These changes in biorhythms and melatonin production result in poor sleep quality because the body does not enter the deeper phases of the sleep cycle as often or as long as is healthy. Studies also show that screen exposure delays the onset of sleep, suppresses REM sleep (which we need to “clean house” and solidify learning), and prevents the body temperature from dropping to levels supportive of deep sleep.23
Without restorative sleep, the brain does not function properly. Muscles become tense, and you feel tired the next day — even if the total sleep time was adequate. To compensate, the body releases more stress hormones to keep you awake, perpetuating a vicious cycle. Even short exposures to electronic screens (such as fifteen minutes) near bedtime can produce these changes. While a screen’s blue tones are much more potent in terms of melatonin suppression, it’s been shown that red light and dimmer displays during evening hours are still quite disruptive.24 Interestingly, a study showed electromagnetic radiation from cell phone towers produced a similar degree of suppression in melatonin,25 suggesting that exposure to a screen device plus EMFs may deliver a “double whammy” of sleep disturbance.
Light-at-Night: Effects on Sleep, Mood, and Cognition
In general, non-restorative sleep is associated with poor memory, irritability, and impaired school or work performance.26 A 2010 sleep study conducted at the JFK Medical Center showed that over half of the children who used electronic media at night not only suffered sleep problems but mood and cognitive problems during daytime.27 Other studies have linked light-at-night from electronics to depression and suicidally,28 and some speculate that disrupted circadian rhythms lead to low serotonin levels — the brain chemical of well-being.29
There is no “safe dose” of after-lights-out texting that does not cause sleep disturbance and daytime sleepiness.30 Teens are notorious for texting at night; some even sleep with their phones. Unfortunately, both children and teens also use the computer in the late afternoons and evenings for schoolwork, making screen-related sleep disturbance a ubiquitous problem.
Reward and Addiction Pathways
There is much discussion today about whether intense video game play or Internet use can be considered an addiction. The relationship between interactive screen-time, addiction, and stress is complex, but a number of key studies shed light on the issue. There is actually an abundance of evidence supporting the concept of screen or tech addiction, but perhaps most convincing are imaging studies. Brain scan research indicates that when heavy gamers — or even individuals who merely crave gaming — are shown computer game cues, their brains “light up” in exactly the same areas as the brain of someone addicted to drugs.31 One study showed that in college students who reported cravings for online gaming, just six weeks of heavy Internet video game playing produced changes in those students’ prefrontal cortex (part of the frontal lobe, the brain’s executive center) similar to those seen in the early stages of addiction.32 Internet and video game addiction studies in adolescent and young adults have found strong physical evidence that brain damage occurs with heavy use.33 Other brain-scan studies have demonstrated that playing video games releases large amounts of dopamine,34 the primary brain chemical associated with reward pathways activated in addiction.
How is all this occurring when there is no toxic “substance”? Compulsive video game and Internet use can be considered an arousal addiction — that is, the user becomes addicted to high levels of stimulation and arousal and then needs more stimulation to achieve or sustain that feeling. Tolerance occurs because reward pathways — the exact same reward pathways in the brain that are involved in chemical addictions — become overactivated. In other words, the pathways become desensitized from overuse. Meanwhile, in addition to the “rush”
