09.01.2026The impact of mobile internet on students

At her inaugural lecture, Ronak Jain, who joined the Department of Economic as Assistant Professor for Economics of Development and Child Welfare supported by UNICEF Switzerland in 2024, presented her research on behavioral and development economics, with a particular focus on vulnerable population groups such as children, adolescents, and workers in the informal sector.

First, Jain explored the role of prosocial preferences in market dynamics. Her research in Delhi reveals that economic transactions are not purely impersonal: buyers are twice as likely to purchase identical goods from child sellers rather than from adult sellers. This finding demonstrates that social and emotional preferences significantly shape market behavior and can play a crucial role in enabling economically weaker actors to survive in competitive environments.

Second, Jain highlighted cost-effective interventions to enhance student performance. Studies conducted in Pakistan and Kenya show the remarkable effectiveness of simple behavioral interventions in resource-constrained education systems. Personalized messages from teachers conveying high expectations led to substantially improved mathematics performance. Likewise, incentives awarded at the class level not only boosted student outcomes across multiple subjects but also increased teacher motivation and attendance.

Global Evidence on Mobile Internet’s Harmful Effects

The third and central focus of the lecture was the causal effects of mobile internet on adolescents. In her main project, conducted with Samuel Stemper, Jain examines the global impact of access to mobile high-speed internet (3G) on teenagers worldwide. Mobile internet usage among adolescents has exploded over the past two decades (today, one in three internet users globally is a child) sparking intense debate about potential harm and calls for smartphone bans in schools, such as those proposed by UNESCO. Yet rigorous causal evidence on effects beyond the school context has been scarce.

Using data from over 2.5 million 15-year-old students across 82 countries, the study finds clear negative consequences. The rollout of 3G led to near-universal smartphone ownership among students, with weekly online time rising by an additional five hours to approximately 35 hours—the equivalent of a full-time job. Notably, 80% of this increase occurred outside school hours.

Academically, the introduction of 3G caused a significant decline in test scores in mathematics, science, and reading, equivalent to a learning loss of about three months. These negative effects were disproportionately larger for disadvantaged groups like girls, students in low- and middle-income countries, and those whose parents lack a university degree, thereby widening educational inequalities.

On the social front, social media usage surged by 17 percentage points, yet this did not strengthen social connections. Instead, students’ sense of belonging at school declined markedly, and they reported greater difficulty in forming friendships.

Jain concludes that while mobile internet is a powerful tool, its uncontrolled use has demonstrable adverse effects on learning and well-being. Responsibility for addressing these harms is shared, meaning that families must actively support healthy screen habits and set clear guidelines for screen time, since most usage happens at home, while schools should provide more offline opportunities for social interaction and teach digital literacy and self-regulation skills from an early age.

Looking ahead, Jain’s next major research agenda will investigate the impacts of artificial intelligence (AI) on the development and well-being of children and adolescents.

Watch the full inaugural lecture here.