High-speed internet and early childhood development: Causal evidence from a countrywide programme

The rapid expansion of high-speed internet has intensified concerns about how digital technologies affect early childhood. Using the staggered rollout of fibre optic to the home in Uruguay as a natural experiment, this column finds that greater lifetime exposure to high-speed internet reduces children’s scores in communication, problem solving, personal-social and socio-emotional skills. The effects are partly explained by indirect channels, through the displacement of valuable activities for child development and alterations in caregivers’ behaviour.

Over the past decade, children have been engaging with digital screens at increasingly younger ages. The proliferation of internet-connected devices – smartphones, tablets, smart TVs – has made screens a ubiquitous feature of the home environment for toddlers and preschoolers (Goode et al. 2019, Holloway et al. 2013, Rideout et al. 2013). At the same time, the supply of content aimed specifically at young children has exploded: streaming platforms now offer dedicated children’s sections, app stores are flooded with tools targeting children from infancy, and YouTube Kids alone reaches tens of millions of households (DeLoache and Chiong 2009, Harwell 2016, YouTube 2021). New information and communication technologies have become a common element of everyday life from the very first years of life (Kardefelt Winther et al. 2019), and children are starting to use internet-connected devices at earlier ages (Chen and Adler 2019). Considering that the foundations of cognitive and socio-emotional development are laid during the first years of life (Heckman 2008, WHO 2020) a relevant question is: what happens to a child’s development when high-speed internet enters the home during those years?

Regarding this question, the medical literature on screen time and child development is vast but relies heavily on correlational studies and small controlled experiments (Anderson and Kirkorian 2015, Kostyrka-Allchorne et al. 2017, Gottschalk 2019). Moreover, most of it concerns traditional television, not the modern internet environment children are growing up in today. On the other side, the economics literature has analysed effects on older children and adolescents – finding that broadband access can hurt school performance (Vigdor et al. 2014, Belo et al. 2014), increase mental health disorders (Donati et al. 2025, Arenas-Arroyo et al. 2025), and worsen socioemotional wellbeing (Colombo et al. 2025). But the first years of life have remained largely unexamined. This is the gap our research addresses in a recent study (Colombo and Failache 2026).

A natural experiment in Uruguay

Uruguay offers an unusually clean setting to study this question. Starting in 2010, the state-owned telecommunications operator ANTEL rolled out the fibre optic to the home (FTTH) network to all households with a fixed telephone line, free of charge and without requiring pre-registration. The deployment was gradual and geographically staggered across the country’s neighbourhoods, reaching 83% of eligible households by 2018. Because the timing of installation in any given neighbourhood was driven by engineering and infrastructure logistics – not by household demand or prior internet use – it provides conditionally exogenous variation to estimate causal effects.

We combine administrative data on the FTTH rollout at the neighbourhood level, with the Nutrition, Child Development and Health Survey, a nationally representative survey of urban children between 0 and 5 years of age, born between 2010 and 2018. Crucially, this survey assessed child development using two internationally validated instruments: the Ages and Stages Questionnaires Third Edition (ASQ-3), which covers communication, gross motor, fine motor, problem solving, and personal-social skills; and the Ages and Stages Questionnaires Socio-Emotional (ASQ-SE), which measures socio-emotional development. 

Our key variable captures each child’s cumulative exposure to FTTH accessibility from birth to the date of assessment – a measure that varies both across birth cohorts and across neighbourhoods. By comparing children of the same age, in the same neighbourhood, but born in different years, we isolate the effect of growing up with faster internet. We verify that children with different FTTH exposure levels are comparable on pre-determined characteristics. 

Greater internet access worsens key developmental outcomes

Our results show that greater exposure to high-speed internet during early childhood reduced several dimensions of child development. A 10-percentage point increase in cumulative exposure to fibre optic decreased development scores by 6% to 17% of a standard deviation in communication, problem solving, personal-social, and socio-emotional skills (Figure 1). 

Figure 1 Effects of FTTH exposure on continuous outcomes

Notes: Confidence intervals at the 5% confidence level using Wild Cluster Bootstrap.

The effects also show up in a clinically meaningful way. FTTH exposure reduces the probability that a child is developing within normal ranges – as opposed to being flagged for monitoring or at risk of developmental delays – by 21 to 33 percentage points for communication and socio-emotional skills. A dose-response analysis confirms that the negative effects grow monotonically with the intensity of exposure, providing further confidence in a causal interpretation (Figure 2).

Figure 2 Effects of FTTH exposure by decile of exposure

Notes: Confidence intervals at the 10% confidence level using Wild Cluster Bootstrap.

The negative effects are larger among children with more educated parents. This pattern may seem surprising if one expects more educated households to be better able to guide children’s use of technology. One possible explanation is differential take-up: households with more educated parents may have been more likely to switch to fibre optic plans once the infrastructure became available. Another possibility is that the opportunity cost of changes in adult–child interactions is higher in households where these interactions would otherwise be more developmentally productive.

The indirect channels: Caregivers matter

We investigate two broad types of mechanism. The first is the direct channel: children’s own exposure to screens. We find no statistically significant effect of FTTH exposure on children spending more than one hour per day in front of a screen – the threshold recommended by health institutions – nor on caregivers’ acceptance of using screens to entertain children without supervision. We interpret this as insufficient evidence to confirm the direct channel with our data, rather than as evidence that it is not operating: our measures of screen time have significant limitations, and we cannot rule out that direct exposure is also playing a role.

What we can say more confidently is that indirect channels are operating. First, households with greater FTTH exposure have fewer children’s books, suggesting that internet access displaces activities that are especially valuable for early cognitive development. Second, adult internet use rises significantly in response to FTTH rollout, consistent with caregivers spending more time on connected devices. Third, we observe a positive (though imprecisely estimated) effect on risky parental practices.

These findings carry an important message for the policy debate. Much of the public conversation about children and technology focuses on regulating how long children themselves spend in front of screens. Our results show that this framing is incomplete: indirect effects operating through caregivers are clearly present. When adults engage more with the internet, the quality and quantity of their interactions with young children is likely to decline – a risk that should be emphasized as much as children’s own screen exposure.

Policy implications

These findings have three implications for policy. First, they do not imply that expanding internet access is undesirable. High-speed internet can generate important benefits for education, work, communication, and access to public services. Digital inclusion remains a central goal, especially in countries where lack of access can reinforce existing inequalities.

Second, the benefits of connectivity should be accompanied by policies and guidance that help families manage digital technologies inside the household. Public information campaigns often focus on recommended limits to children’s screen time. Our results suggest that this advice should be broadened. Guidance should also address adult device use around young children, and the importance to generate moments of interaction that are device-free.

Third, early childhood policy should treat digital technology as part of the home learning environment. Programmes that promote parenting skills, child development, and early stimulation could incorporate simple messages about digital habits. For example, they could encourage caregivers to preserve time for reading and play, avoid using screens as a default substitute for interaction, and become aware of how their own internet use may affect the attention they give to children.

Finally, an important caveat deserves emphasis. It is possible that exposure to digital technologies in early childhood is building new skills or abilities that our current tests do not capture, that may prove valuable in future labour markets. Given that exposure to digital technologies during early childhood is a relatively recent phenomenon, we may only be able to fully comprehend it in the years to come. 

The broader lesson is not that technology is harmful in itself. The effects of digital technologies depend on how they are used, by whom, and in what context. High-speed internet changes the household environment in ways that can matter for early childhood development. A policy debate focused only on access, or only on children’s screen time, misses this broader mechanism. To maximise the benefits of connectivity while reducing potential risks, digital inclusion policies should be complemented by early childhood guidance that recognises the role of caregivers, family routines, and the quality of interactions at home.

Source : VOXeu