This study is in line with earlier research. One could argue if the negative effects of screen time are actually because of watching screens or underlying causes, but this is less important in this case. The researchers behind this new study have found that, although more screen time at 2 years of age is associated with poorer communication and daily living skills at age 4, time spent playing outdoors can mitigate these effects on daily living skills.

From the press release:

In the study, which will be published in March in JAMA Pediatrics, the researchers followed 885 children from 18 months to 4 years of age. They looked at the relationship between three key features: average amount of screen time per day at age 2, amount of outdoor play at age 2 years 8 months, and neurodevelopmental outcomes — specifically, communication, daily living skills, and socialization scores according to a standardized assessment tool called Vineland Adaptive Behavior Scale-II — at age 4.

“Although both communication and daily living skills were worse in 4-year-old children who had had more screen time at aged 2, outdoor play time had very different effects on these two neurodevelopmental outcomes,” explains Kenji J. Tsuchiya, Professor at Osaka University and lead author of the study. “We were surprised to find that outdoor play didn’t really alter the negative effects of screen time on communication — but it did have an effect on daily living skills.”

Specifically, almost one-fifth of the effects of screen time on daily living skills were mediated by outdoor play, meaning that increasing outdoor play time could reduce the negative effects of screen time on daily living skills by almost 20%. The researchers also found that, although it was not linked to screen time, socialization was better in 4-year-olds who had spent more time playing outside at 2 years 8 months of age.

“Taken together, our findings indicate that optimizing screen time in young children is really important for appropriate neurodevelopment,” says Tomoko Nishimura, senior author of the study. “We also found that screen time is not related to social outcomes, and that even if screen time is relatively high, encouraging more outdoor play time might help to keep kids healthy and developing appropriately.”

These results are particularly important given the recent COVID-19-related lockdowns around the world, which have generally led to more screen time and less outdoor time for children. Because the use of digital devices is difficult to avoid even in very young children, further research looking at how to balance the risks and benefits of screen time in young children is eagerly awaited.

Abstract of the study:

Importance  Whether the association between higher screen time in infancy and later suboptimal neurodevelopment can be mitigated by frequency of outdoor play is unknown.

Objective  To investigate whether higher screen time at age 2 years is associated with neurodevelopmental outcomes at age 4 years and whether this association is mediated by frequency of outdoor play at age 2 years 8 months.

Design, Setting, and Participants  Participants were a subsample of the Hamamatsu Birth Cohort Study for Mothers and Children (HBC Study, N = 1258). Children were born between December 2007 and March 2012 and followed up from 1 year 6 months to 4 years. The analysis was conducted from April 2021 to June 2022.

Exposures  Screen time longer than 1 hour a day at age 2 years was coded as higher screen time.

Main Outcomes and Measures  Standardized scores for communication, daily living skills, and socialization domains of the Vineland Adaptive Behavior Scale, second edition, at age 4 years were used (mean [SD], 100 [15]). The mediating factor was frequency of outdoor play at age 2 years 8 months, with 6 or 7 days per week coded as frequent outdoor play.

Results  Of 885 participants, 445 children (50%) were female; mean (SD) screen time per day was 2.6 (2.0) hours. Causal mediation analyses revealed that higher screen time at age 2 years was associated with lower scores in communication at age 4 years (nonstandardized coefficient b = −2.32; 95% CI, −4.03 to −0.60), but the association was not mediated by frequency of outdoor play. Higher screen time was also associated with lower scores in daily living skills (b = −1.76; 95% CI, −3.21 to −0.31); 18% of this association was mediated by frequency of outdoor play. Frequency of outdoor play was associated with socialization (b = 2.73; 95% CI, 1.06 to 4.39), whereas higher screen time was not (b = −1.34; 95% CI, −3.05 to 0.36).

Conclusions and Relevance  Higher screen time at age 2 years was directly associated with poorer communication at age 4 years. It was also associated with daily living skills, but frequency of outdoor play at age 2 years 8 months alleviated it, suggesting outdoor play mitigated the association between higher screen time and suboptimal neurodevelopment. Future research should specify the nature of the associations and intervention measures, enabling targeted interventions that reduce the potential risk in screen time.