---
title: "Screens before age two linked to slower development, major UK review finds"
description: "A review of thousands of studies has concluded that screen time in the first two years of life is associated with delayed communication, weaker problem-solving and disrupted sleep — even as most toddlers far exceed the limited screen use that health authorities advise. Researchers stress the evidence shows association, not proof of cause."
category: "Science"
category_url: https://newsparlor.com/category/science
author: "Liam Fitzgerald"
published: 2026-06-27T09:05:00.000Z
updated: 2026-06-27T09:05:00.000Z
canonical: https://newsparlor.com/article/screen-time-under-twos-development-study
tags: ["child-development", "screen-time", "toddlers", "language", "pediatric-health", "who"]
---
# Screens before age two linked to slower development, major UK review finds

A review of thousands of studies has concluded that screen time in the first two years of life is associated with delayed communication, weaker problem-solving and disrupted sleep — even as most toddlers far exceed the limited screen use that health authorities advise. Researchers stress the evidence shows association, not proof of cause.

A systematic review of the evidence on infants and screens has concluded that the devices may be interfering with development during a uniquely sensitive window — the first two years of life — when the brain is forming connections at a furious pace. But the researchers are careful to frame their findings as associations, not proof of cause.

## What the review looked at

The review, titled *From Teddies to Tablets*, was [commissioned by the 1001 Critical Days Foundation](https://www.1001criticaldays.com/press-releases/from-teddies-to-tablets-press-release) and carried out by researchers across several UK universities, drawing together evidence from a large body of peer-reviewed studies. It found that screen exposure now often begins in the first year of life, and that a portion of two-year-olds are watching for two hours a day or more — well beyond official guidance.

Greater screen use in the second year was linked to delayed communication and weaker problem-solving. Sleep emerged as a consistent theme, with research suggesting that more daily touchscreen use is associated with less sleep in young children — a meaningful loss given that sleep helps consolidate early learning.

## Scale from a large English study

Separate work gives a sense of how widespread the behavior is. The UCL-led [Children of the 2020s study](https://cls.ucl.ac.uk/toddlers-spending-two-hours-on-screens-a-day/), drawing on more than 4,700 parents of two-year-olds in England, found that 98% of children that age used screens on a typical day, for an average of about 129 minutes — and that only about a third met the World Health Organization's guideline of no more than 60 minutes. Children in the heaviest-use group scored lower on a spoken-vocabulary assessment than those with minimal exposure, and were more likely to show signs of emotional or behavioral difficulty.

## Why screens might harm — and the caveats

The leading proposed mechanism is simple: time in front of a screen displaces the back-and-forth human interaction — caregiver talk, shared attention, hands-on play — that drives early brain development. A baby's brain builds connections at an extraordinary rate, and that construction depends on responsive, real-world input that passive viewing does not supply. Device light late in the day may compound the effect by disrupting sleep.

Researchers are explicit about the limits of the evidence, however. The UCL team noted its study did not look at what children were watching or whether they viewed alongside a parent — both of which likely matter. Reviews in this field have also flagged that many studies fail to fully account for confounding factors such as household income and parental education; in the UCL data, lower-income families reported markedly more toddler screen time, suggesting screen use may partly be a marker of wider circumstances rather than a standalone cause. No long-term randomized trials — difficult to run ethically — yet exist to isolate the effect cleanly.

## What the guidance says

Official advice has been firm for years. The [WHO's 2019 guidelines](https://www.who.int/news/item/24-04-2019-to-grow-up-healthy-children-need-to-sit-less-and-play-more) recommend no screen time at all for children under one, and no sedentary screen time for one- to two-year-olds, apart from video calls with family. The American Academy of Pediatrics similarly advises avoiding screens other than video chat before about 18 months.

The gap between that guidance and reality is wide. What the growing body of evidence supports, researchers say, is not a precise "safe dose" but a broader caution: the first two years are a window that does not come again, and time spent passively watching a screen is time not spent in the kind of interaction a child cannot easily make up later.