Screens and the Developing Brain: How Digital Use Impacts Brain Structure and Behaviour
This article explores the relationship between screens and the developing brain, the influence on the structure, functionality, and how this is replacing previously learned skills. It is advised to read the preceding article: Conditioning & Neuroplasticity: How Experiences Shape Developing Brains before this one as the concepts of learning from experiences tie together.
Technological advances have made screen media activity (SMA) one of the most influential environmental factors for today’s youth. This includes everything from television and video games to social media and mobile devices. As children grow up in increasingly digital environments, researchers have begun to examine how screen exposure affects the brain’s structural development and how these changes relate to both internal and external affects such as attention, emotion, and behaviour.
The ABCD Study: A Primary Data Source
A key source of information for this blog is the Adolescent Brain Cognitive Development (ABCD) Study. This large-scale, longitudinal research project is the most comprehensive study of brain development and child health in the United States to date. It tracks the biological and behavioural development of over 11,000 children from age 9 to 10 into early adulthood, using neuroimaging, cognitive tasks, and behavioural surveys.
Whilst research using data from this study was the primary inspiration for this blog, the contents of this blog are drawn from a review of a wide range of articles. In some cases, these provided validation of the findings, while in others they contained a different perspective or theories. It is important to note that at this stage there has been no research definitively identifying causality, only strong correlations.
Structural Brain Changes from Screen Use
Prefrontal Cortex
The prefrontal cortex, which governs complex cognitive behaviours such as decision-making, impulse control, and emotional regulation, is one of the most consistently affected regions in children and adolescents with high levels of screen exposure. Neuroimaging studies have revealed reduced grey matter volume and cortical thickness in the orbitofrontal cortex (OFC), a subregion involved in emotional regulation and behavioural inhibition. Meanwhile, the dorsolateral prefrontal cortex (DLPFC), a critical area for executive functions like working memory and attention control, also demonstrates altered activation in individuals with problematic screen use. Encouragingly, some studies have observed increased DLPFC activity following reduced screen time, suggesting that with the right changes, there may be potential for functional recovery and improved self-regulation.
Whilst the structural changes have so far been limited to children, the functional activity in the DLPFC was also identified in adults engaging in excess screen use (video games and social media). These studies theorized that an emotional numbing effect was occurring as this region reduced in activation and found that it occurred faster in those who engaged more frequently and for longer periods. The brain began to respond to the action of starting the activity rather than once fully engaged.
Striatum and Reward System
The ventral striatum, particularly the nucleus accumbens, plays a central role in the brain’s reward system. In individuals with high levels of screen use, this region shows increased responsiveness to stimuli such as gaming cues and social media interactions. This heightened activity is believed to enhance the perceived reward of screen-based experiences, reinforcing screen-seeking behaviour. Over time, this can create a feedback loop in which digital stimuli become the primary source of dopamine-driven gratification, similar to what is observed in substance use disorders. Functionally, this may contribute to reduced interest in offline activities, impaired impulse control, and an increased focus on instant gratification.
Amygdala and Emotion Processing
The amygdala, involved in emotion processing and motivation, has been shown to shrink in volume in problematic users. This reduction in volume may interfere with a child’s ability to modulate emotional intensity and respond appropriately to social or internal cues. This is also seen in those who have experienced chronic stress or anxiety. The damage has been seen to partially repair with enough recovery time; however, the fact that the repair is only partial means there is an increased predisposition to associated symptoms returning.
Cingulate Cortex
Studies on the anterior cingulate cortex (ACC), a region tied to self-regulation and reward-based learning, have yielded mixed results. While some studies report reduced volume, others show increases, possibly due to compensatory mechanisms. Regardless of direction, alterations in this area have been associated with impaired error monitoring, reduced adaptability in behaviour, and challenges with impulse control. Functionally, this may manifest as difficulties in learning from mistakes or maintaining consistent motivation without immediate rewards.
Parieto-Occipital Regions
These areas, including the right angular gyrus and visual processing regions like the V2 area, show structural differences in individuals with high levels of gaming or screen engagement. These regions are involved in visuospatial awareness and mental rotation skills. While changes here might enhance certain visual processing abilities, such as rapid response to visual cues, they may also reflect a narrowing of cognitive development, with decreased engagement in broader cognitive skills such as divergent thinking, creative exploration, and physical interaction with space and materials.
Functional Connectivity and Network Activity
Beyond individual regions, we can also look at how these structures interact. Screen use has been linked to changes in the brain’s large-scale network architecture. Altered connectivity within and between networks, particularly the default mode network (DMN), salience network (SN), and central executive network (CEN), can reduce the brain’s ability to switch effectively between rest, attention, and goal-oriented tasks. This disrupted coordination may affect working memory, reduce mental flexibility, and impair sustained focus, particularly when switching between tasks or transitioning from rest to cognitive effort. The salience network is used to determine what stimuli need to be paid attention to and manages the balance between the CEN and the DMN. Engaging in excess screen time appears to overtrain the salience network and disrupt the ability to filter some stimuli. This results in more awareness of sounds, textiles, movement, and internal feelings, which disrupts the ability for the CEN to engage and maintain attention and learning.
From Brain Changes to Everyday Function
These neurological changes are not just academic. They influence how children and adolescents think, feel, and behave in everyday life:
- Decreased ability to focus and sustain attention
- Heightened emotional reactivity to everyday stressors
- Reduced tolerance for boredom or tasks without instant rewards
- Impaired decision-making and difficulty controlling impulses
- Increased sensitivity and reactivity to stimuli
- Difficulty with emotional regulation or internal feelings of discomfort
These behavioural outcomes reflect more than just correlation. They demonstrate how screen media activity (SMA) can condition the brain to respond more strongly to digital stimuli while diminishing its ability to function without them. As the brain is repeatedly exposed to quick, high-reward interactions, its neural pathways adapt to prioritise these experiences. This parallels the behavioural conditioning outlined in Part 1, where repeated associations build strong neural expectations. Over time, the brain may become trained to seek out screens as a default response to discomfort, boredom, or even curiosity. This can make it harder to engage in slower, real-world tasks that require sustained effort and self-regulation.
These observed behavioural and emotional effects are further supported by broader research identifying correlations between smartphone use and increased anxiety, stress, reduced sleep quality, symptoms of depression, and suicidal ideation. While causality is not confirmed, the strength and consistency of these associations suggest that high levels of screen interaction may exacerbate underlying vulnerabilities or interfere with the brain’s ability to regulate mood, rest, and stress response. These findings highlight the importance of understanding screen use not only in terms of brain development but also mental health risk.
What’s Being Replaced
Another concern is not just what children are exposed to but what they are missing out on. High levels of screen use often come at the expense of:
- Imaginative play, which is not only critical for cognitive flexibility and emotional processing, but also conditions the brain to tolerate uncertainty, create new scenarios, and explore problem-solving through narrative and self-expression. These types of play strengthen the brain’s ability to envision possibilities, simulate future actions, and manage emotions in pretend scenarios, all important precursors for adaptive behaviour.
- Tactile construction activities, like block-building or drawing, which support spatial reasoning, fine motor skills, and sensory integration. These tasks condition the brain to focus attention on multi-step challenges, experiment with trial-and-error, and experience success through persistence and physical interaction with the environment. Sensory-rich tasks also promote the development of sensory-motor circuits and help balance left-right hemisphere engagement.
- The ability to sit in stillness, observe their surroundings, or entertain themselves without stimulation. This helps condition emotional regulation, builds tolerance for internal states such as boredom or frustration, and strengthens the brain’s capacity for sustained attention and self-guided thought. Stillness and reflective observation help develop the default mode network in natural settings and build resilience to discomfort.
- Respectful conversation and social-emotional repair, which are vital for learning how to navigate relationships. Online interactions often lack visual feedback such as facial expressions or tone of voice, which help activate emotional and reward centres during in-person communication. Without these cues, children may not experience the natural consequences of unkind or inappropriate comments. When playing together in person, a hurt expression or change in tone signals distress, which triggers brain systems involved in empathy, social error detection, and behavioural repair. These interactions teach children how to adjust their behaviour, develop emotional awareness, and build stronger and healthier social connections.
These natural learning opportunities play a vital role in early childhood, laying the groundwork for emotional resilience, creative thinking, and executive function. When replaced by highly stimulating digital content, children may become conditioned to expect constant novelty and instant rewards, potentially undermining their capacity for patience, creativity, and problem-solving in non-digital environments.
Understanding how digital experiences shape developing brains helps us move beyond blame or fear and toward informed guidance. The evidence suggests that screen use can significantly impact brain structure and function, particularly when it replaces critical developmental activities.
As caregivers, educators, and clinicians, recognising these patterns allows us to intervene early, set boundaries, and offer healthier alternatives.
References
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