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Emerging scientific evidence indicates that frequent digital technology use has a significant impact—both negative and positive—on brain function and behavior. Potential harmful effects of extensive screen time and technology use include heightened attention-deficit symptoms, impaired emotional and social intelligence, technology addiction, social isolation, impaired brain development, and disrupted sleep. However, various apps, videogames, and other online tools may benefit brain health. Functional imaging scans show that internet-naive older adults who learn to search online show significant increases in brain neural activity during simulated internet searches. Certain computer programs and videogames may improve memory, multitasking skills, fluid intelligence, and other cognitive abilities. Some apps and digital tools offer mental health interventions providing self-management, monitoring, skills training, and other interventions that may improve mood and behavior. Additional research on the positive and negative brain health effects of technology is needed to elucidate mechanisms and underlying causal relationships.
Keywords: emotional intelligence, digital technology, internet, media, neural activation, online searching
La evidencia científica que está surgiendo muestra que el empleo frecuente de la tecnología digital tiene un impacto significativo, tanto negativo como positivo, en la función cerebral y en el comportamiento. Los posibles efectos nocivos del tiempo prolongado frente a la pantalla y del empleo de la tecnología incluyen síntomas como marcado déficit de atención, deterioro de la inteligencia emocional y social, adicción a la tecnología, aislamiento social, deterioro del desarrollo cerebral y alteraciones del sueño. Sin embargo, hay varias aplicaciones, videojuegos y otras herramientas en línea que pueden beneficiar la salud del cerebro. En las imágenes cerebrales funcionales se ha observado que los adultos mayores vírgenes a internet que aprenden a buscar en línea, muestran aumentos significativos en la actividad neuronal cerebral durante las búsquedas simuladas en internet. Ciertos programas computacionales y videojuegos pueden mejorar la memoria, las destrezas en tareas múltiples, la fluidez de la inteligencia y otras habilidades cognitivas. Hay varias aplicaciones y herramientas digitales que ofrecen intervenciones en salud mental y que proporcionan automanejo, monitoreo, capacitación junto a otras intervenciones que pueden mejorar el estado de ánimo y el comportamiento. Se require de investigación adicional acerca de los efectos positivos y negativos de la tecnología sobre la salud del cerebro para dilucidar los mecanismos y las relaciones causales subyacentes.
D’après de nouvelles données scientifiques, l’usage fréquent des technologies numériques influe significativement sur le comportement et le fonctionnement cérébral, de façon aussi bien négative que positive. Une pratique excessive des écrans et des technologies numériques peut avoir des effets néfastes comme des symptômes de déficit d'attention, une intelligence émotionnelle et sociale altérée, une dépendance à la technologie, un isolement social, un développement cérébral dégradé et des troubles du sommeil. Cependant, certaines applications, jeux vidéo et autres outils en ligne peuvent avoir des effets bénéfiques sur le cerveau. L'imagerie fonctionnelle montre une activité neuronale significativement augmentée chez des personnes âgées jamais exposées à Internet et qui apprennent à faire des recherches en ligne. Certains programmes informatiques et jeux vidéo peuvent améliorer la mémoire, les compétences multitâches, l'agilité de l’intelligence et d'autres capacités cognitives. Dans le domaine de la santé mentale, différents outils et applications numériques permettant l'autogestion, le suivi, l'acquisition de compétences et d'autres techniques sont susceptibles d'améliorer l'humeur et le comportement du patient. Les effets positifs et négatifs de la technologie sur la santé cérébrale nécessitent d’être encore étudiés afin d’en mieux comprendre les mécanismes et les relations de cause à effet.
During the past three decades, digital technology has transformed our daily lives. People at every age are now taking advantage of the vast amounts of available online information and communication platforms that connect them with others. This technology helps us to generate, store, and process enormous amounts of information and interact with each other rapidly and efficiently.
Most adults use the internet daily, and nearly one out of four report being online most of the time. 1 Because of this transformation to an online world, neuroscientists have begun focusing their attention on how digital technology may be changing our brains and behavior. The emerging data suggest that constant technology use impacts brain function and behavior in both positive and negative ways. For example, older individuals suffering from cognitive decline could use the internet to access information to help them remain independent longer; however, many seniors with cognitive complaints are reluctant or unable to adopt new technologies. 2 Our group’s functional magnetic resonance imaging (MRI) research tracking neural activity during simulated internet searches suggests that simply searching online may represent a form of mental exercise that can strengthen neural circuits. 3 By contrast, the persistent multitasking that is characteristic of most technology users impairs cognitive performance. 4 In this review, we highlight some of the research suggesting potential benefits and possible risks of using digital technology.
Multiple studies have drawn a link between computer use or extensive screen time (eg, watching television, playing videogames) and symptoms of attention-deficit hyperactivity disorder (ADHD). A 2014 meta-analysis indicated a correlation between media use and attention problems. 5 A recent survey of adolescents without symptoms of ADHD at the start of the study indicated a significant association between more frequent use of digital media and symptoms of ADHD after 24 months of follow-up. 6 Although most of the research linking technology use and ADHD symptoms has involved children and adolescents, this association has been identified in people at any age. 7
The reason for the link between technology use and attention problems is uncertain, but might be attributed to repetitive attentional shifts and multitasking, which can impair executive functioning. 8 Moreover, when people are constantly using their technology, they have fewer opportunities to interact offline and allow their brain to rest in its default mode. 9
Because of concern that a young, developing brain may be particularly sensitive to chronic exposure to computers, smartphones, tablets, or televisions, the American Academy of Pediatrics has recommended that parents limit screen time for children aged 2 years or younger, when the brain is particularly malleable. 10 Spending extensive periods of time with digital media translates to spending less time communicating face to face. 11
Kirsh and Mounts 12 explored the hypothesis that playing videogames would interfere with the ability to recognize emotions conveyed through facial expressions. They examined the effects of playing videogames on recognition of facial expressions of emotions in 197 students (ages 17 to 23 years). Participants played violent videogames before watching a series of calm faces morph into either angry or happy faces. Participants were asked to quickly identify the emotion while the facial expression changed. The authors found that happy faces were identified faster than angry faces, and that playing violent videogames delayed happy-face recognition time.
Our team at the University of California, Los Angeles (UCLA) 13 hypothesized that preteens restricted from screen-based media would have more opportunities for face-to-face interactions, which would improve their ability to recognize nonverbal emotional and social cues. We studied 51 schoolchildren who spent five days at an overnight nature camp where television, computers, and smartphones were forbidden, and compared them with 54 school-based matched controls who continued their usual media practices (4 hours of screen time per day). At baseline and after 5 days, participants were assessed for their ability to recognize emotions from photographs of facial expressions and videotaped scenes of social interactions (without verbal cues). After 5 days, the nature camp participants restricted from screen time demonstrated significantly better recognition of nonverbal emotional and social cues than participants who continued their usual daily screen time. These findings suggest that time away from screen-based media and digital communication tools improves both emotional and social intelligence.
Although not formally included in the Diagnostic and Statistical Manual of Mental Disorders , 14 excessive and pathological internet use has been recognized as an internet addiction, which shares features with substance-use disorders or pathological gambling. Common features include preoccupations, mood changes, development of tolerance, withdrawal, and functional impairment. 15 ,16 The global prevalence of internet addiction is estimated at 6%, but in some regions such as the Middle East the prevalence is as high as 11%. 17 Students with internet addiction are more likely to suffer from ADHD symptoms than from other psychiatric disorders. 18 You and colleagues 16 reported that schoolchildren with internet addiction experienced significantly greater symptoms of inattention, hyperactivity, and impulsivity than non–internet-addicted students. Panagiotidi and Overton 19 reported greater ADHD symptoms in adults aged 18 to 70 years with internet addiction: predictors of addiction included younger age, playing massively multiplayer online role-playing games, and spending more time online. Despite consistent associations between ADHD symptoms and internet addiction, a causal relationship has not been confirmed. It is possible that people with ADHD symptoms have a greater risk for developing technology addiction, but an alternative explanation is that extensive technology use from addictive behavior causes ADHD symptoms.
Ninety percent of young adults in the United States use social media platforms such as Facebook, Twitter, Snapchat, and Instagram, and most visit these sites at least daily. 20 Paradoxically, social media use is linked to social isolation (ie, a lack of social connections and quality relationships with others), 21 which is associated with poor health outcomes and increased mortality. 1
Primack and colleagues 20 studied 1787 young adults (ages 19 to 32 years) and found that using social media 2 or more hours each day dou-
bled the odds for perceived social isolation compared with use less than 30 minutes each day. Similar associations between perceived social isolation and social media use were observed in 213 middle-aged and older adults. 22 Possible explanations for such findings include reduced offline social experiences and the tendency to make upward social comparisons based on highly curated social media feeds that produce unrealistic expectations of oneself. 1 Future research should explore casual explanations for such relationships and seek ways to address the needs of people who may benefit from social media–based interventions, such as geographically isolated individuals.
Screen time may also adversely impact cognitive and brain development. In a recent review, children under age 2 were reported to spend over 1 hour each day in front of a screen; by age 3, that number exceeded 3 hours. 23 Increased screen time (and less reading time) has been associated with poorer language development and executive functioning, particularly in very young children, 24 as well as poorer language development in a large cohort of minority children. 25 In infants, increased screen time was one of several factors that predicted behavioral problems. 26 For infants 6 to 12 months, increased screen time was linked to poorer early language development. 27 In children of preschool age and older, digital media directed toward active learning can be educational, but only when accompanied by parental interaction. 23
Recent research has examined the effects of media exposure on brain development. In a study of children aged 8 to 12 years, more screen and less reading time were associated with decreased brain connectivity between regions controlling word recognition and both language and cognitive control. 24 Such connections are considered important for reading comprehension and suggest a negative impact of screen time on the developing brain. Structurally, increased screen time relates to decreased integrity of white-matter pathways necessary for reading and language. 28 Given the growing prominence of screen use among even very young children at stages when brain plasticity is greatest, there is significant concern about the cognitive and brain development of the current generation of screen-exposed children that requires greater understanding
Recent studies indicate that screen exposure disrupts sleep, which can have a negative effect on cognition and behavior. Daily touch-screen use among infants and toddlers was shown to negatively impact sleep onset, sleep duration, and nighttime awakenings. 29 In adolescents, more time using smartphones and touch screens was associated with greater sleep disturbances, and tablet time was associated with poor sleep quality and increased awakenings after sleep onset. 30 In adults, increased smartphone use was associated with shorter sleep duration and less efficient sleep. 31 Poor sleep quality is associated with brain changes, such as reduced functional connectivity and decreased gray-matter volume, as well as an increased risk for age-associated cognitive impairment and Alzheimer disease. 32,33
It is unclear whether the act of looking at screens or media content disrupts sleep; however, it is well-known that the wavelength of light exposure affects the circadian rhythms that govern sleep. Computer and phone light-emitting diode (LED) screens emit slow wave, blue light that interferes with circadian rhythms. Exposure to LED versus non-LED screens has been shown to produce changes in melatonin levels and sleep quality, and such exposure decreases cognitive performance. 34 Thus, it is important to recognize the effects of screen time on sleep as a moderator of various negative effects on cognition and brain function.
Despite these potential harmful brain-health effects of digital technology, emerging evidence points to several benefits for the aging brain in particular, including opportunities for brain-strengthening neural exercise, cognitive training, and the online delivery of mental-health interventions and support ( Table I
| Strategies | Brain-Health Promoting Targets |
| Online searching | Neural activation of circuits controlling decision-making and complex reasoning |
| Cognitive training games | Global cognition, memory (immediate, delayed, and working), attention, learning abilities |
| Racecar videogames with distracting road signs | Multitasking skills |
| N-back task training games | Working memory, fluid intelligence |
| Action videogames | Visual attention, reaction time, task-switching abilities |
| Monitoring apps | Heart rate, breathing patterns |
| Psychotherapy, educational apps | Mood, sleep, social support |
Functional neuroimaging allows scientists to observe regional neural activity during various mental tasks. Our group was the first to explore neural activity using functional MRI while research volunteers performed simulated internet searching. 3 Previous studies suggested that mentally challenging tasks, such as searching online, may benefit brain health and even delay cognitive decline. 35,36 We focused on internet searching because it is so common among people of all ages. 37
We assessed patterns of brain neural activation in 24 cognitively normal middle-aged and older adults (ages 55 to 76 years): 12 of them had minimal internet search experience (net-naive group), and 12 had extensive experience (net-savvy group). In addition to the internet-search task, we used a control task of reading text on a computer screen formatted to simulate a printed book layout.
We found that text reading activated brain regions controlling language, reading, memory, and visual abilities (left inferior frontal, temporal, posterior cingulate, parietal, and occipital regions), and the magnitude and extent of activation were similar in the net-naive and net-savvy groups. During internet searching, net-naive subjects displayed activation patterns similar to those observed while reading text. However, net-savvy subjects demonstrated significant activity in neural signal intensity in additional regions controlling decision-making, complex reasoning, and vision (frontal pole, anterior temporal region, anterior and posterior cingulate, and hippocampus). During the internet-search task, the net-savvy group displayed a more than twofold increase in the extent of activation in the major regional clusters compared with the net-naive group (21 782 versus 8646 total activated voxels).
These findings suggest that searching online may be a form of brain neural exercise. Other research indicates that after several months, daily computer-game playing leads to reduced cortical neural activity. 38 Our other research indicates that memory training, along with healthy lifestyle behaviors (eg, physical exercise, healthy diet), leads to reduced dorsal prefrontal cortical metabolism after 2 weeks. 36 Such findings suggest that task repetition over time leads to lower neural activity during the task, which could reflect greater cognitive efficiency after mental training.
One model that could explain such findings is that novel and stimulating mental experiences, such as searching on the internet, initially lead to minimal activation before the internet user discovers strategies for solving the unfamiliar mental challenge. After such insights, a broader neural network is engaged. After repeated sessions, the initially novel mental task becomes routine and repetitive, no longer posing a mental challenge. The lower activity observed may thus reflect a more efficient neural response. These results also suggest that previous internet-search experience may alter the brain’s responsiveness in neural circuits controlling decision-making and complex reasoning. The net-savvy volunteers showed increased activation during the internet-search task, which suggests that internet searching may remain a novel and mentally stimulating process even after continued practice.
We also used functional MRI to record brain neural activity during simulated internet-search tasks in 12 net-naive and 12 net-savvy subjects before and after internet training. 39 Based on our previous findings, we hypothesized that net-naive volunteers would recruit a larger frontal lobe network after internet training and that net-savvy volunteers would show either no increase or a decrease in activation after training because of greater cognitive efficiency due to training.
The training consisted of brief instructions on how to search online along with practice sessions (1 hour per day for a week). To increase motivation, participants were told that they would be quizzed on their knowledge of assigned search topics after the experiment.
During their first session, net-naive subjects recruited a neural network that included the superior, middle, and inferior frontal gyri, as well as the lateral occipital cortex and occipital pole. During the second session (after internet training), additional regions in the middle and inferior frontal gyri were recruited only in the net-naive group. By contrast, during their first scan session, the net-savvy subjects recruited a cortical network that, though overlapping with that of the net-naive subjects, showed more extensive regions of activation ( Figures 1 and 2 ). This cortical network included regions that control mental activities supporting tasks required for internet searches, including decision-making, working memory, and the ability to suppress nonrelevant information. Moreover, net-savvy participants showed a pattern of activation that was reduced after the training. This reduction is consistent with our hypothesis that the brain becomes more efficient and possibly habituates to the internet task over time. Overall, these findings suggest that internet searching for relatively short periods of time can change brain-activity patterns in middle-aged and older adults.
Other groups have explored the effects of internet-search training on brain structure and function. Dong and associates 40 studied the influence of short-term internet-search training on white-matter microstructure via diffusion tensor imaging. After 6 training days, they found that the 59 participants (mean age 21 years) showed increased fractional anisotropy (diffusion tensor imaging scans) in the right superior longitudinal fasciculus and within that region, decreased radial diffusivity. These findings suggest that short-term internet-search training may increase white-matter integrity in the right superior longitudinal fasciculus, which could result from increased myelination.
Internet-searching task activations before and after training in internet-naive and internet-savvy subjects. Areas of activation are indicated in blue for baseline and in red for patterns after training.
