Screen use and shared book reading are both woven into modern childhood, but they compete for something families cannot expand: time. A new longitudinal study suggests that this competition may operate in both directions during the preschool years.
Researchers following 2,164 children in Taiwan found that when a child had more shared book reading than was usual for that child, the child tended to have less screen exposure at the next measurement. The reverse pattern also appeared. Higher-than-usual screen exposure predicted less subsequent shared reading.
The findings, published in Scientific Reports on 3 October 2026, are important because they move beyond a simple comparison between children who use screens more and children who read more. By using a random intercept cross-lagged panel model, the researchers separated relatively stable differences between families from changes occurring within the same child over time.
Following children from age three to five
The study drew on the Kids in Taiwan: National Longitudinal Study of Child Development and Care, a large developmental dataset. The analysis included 2,164 children whose caregivers reported their activities at 36, 48 and 60 months of age.
At each wave, caregivers reported children’s daily screen exposure and weekly shared book reading. Screen exposure captured time spent with digital media, while the reading measure reflected shared reading activity between children and caregivers. This gave the researchers three observations spanning a period in which children’s language, attention, routines and independence develop rapidly.
The central methodological challenge was distinguishing two different questions. First, do children who generally spend more time on screens also tend to experience less shared reading than other children? Second, when an individual child temporarily spends more time than usual on one activity, does that change predict what happens to the other activity later?
Traditional cross-lagged models can blur these levels. The random intercept cross-lagged panel model used here separates stable between-child differences from within-child fluctuations. That distinction makes the longitudinal result more informative, although it still does not establish causation.
Screen and reading habits were both persistent
Both behaviours showed stability across the three measurement waves. In practical terms, children who tended to have relatively high screen exposure at one age often remained relatively high compared with their peers later, while shared reading habits also showed continuity.
The stable, between-child components of the two behaviours were moderately negatively related. The reported random-intercept correlation was approximately r = -0.216, with p < 0.001. This indicates that children with persistently higher screen exposure tended, on average, to have persistently lower shared reading, although the relationship was far from perfect.
More importantly, the within-child analysis showed reciprocal negative cross-lagged associations. When shared reading rose above a child’s own typical level, subsequent screen exposure tended to fall. When screen exposure rose above that child’s typical level, subsequent shared reading tended to fall. The effects were small, with at least one reported cross-lagged coefficient around β = -0.052, but statistically significant.
A small coefficient is not evidence that the finding is unimportant. Preschool routines are repeated across hundreds of days, and small shifts can accumulate. At the same time, the effect size is a reason not to claim that reading automatically displaces large amounts of screen time, or that screens inevitably crowd books out of family life.
Why the reciprocal pattern matters
Much public discussion treats screen exposure as the active behaviour and reading as the activity that suffers. The new analysis suggests a more dynamic relationship. Shared reading may also be part of the process shaping later screen routines.
One straightforward explanation is time displacement. A preschool child’s day contains a limited number of discretionary periods. If families establish more frequent reading routines, fewer opportunities may remain for screens. If screens occupy more of those periods, shared reading may become less frequent.
But time competition is unlikely to be the only mechanism. Family routines can reinforce themselves. A regular bedtime story may create expectations about what happens before sleep, just as habitual device use during meals, travel or calming periods can become embedded in daily family life. The longitudinal findings are consistent with these possibilities but do not identify which mechanism is responsible.
The results also caution against interpreting screen behaviour in isolation. A family’s media environment includes what children watch, whether caregivers participate, why screens are used, what alternatives are available and how routines are organised. Two children with the same number of screen minutes can therefore have very different developmental experiences.
A stronger design than a one-time survey, but not a causal experiment
The three-wave design is a major strength because it establishes temporal ordering. The researchers did not simply observe that screen use and reading were correlated at one point in time. They examined whether deviations in one behaviour preceded later deviations in the other while accounting for stable individual differences.
However, temporal ordering does not by itself prove causality. An unmeasured change could influence both behaviours. A new sibling, a caregiver’s work schedule, childcare arrangements, illness, household stress or changing parental rules could alter screen exposure and shared reading together.
The measures were also based on caregiver reports rather than passive device logs or direct observations. Parents may underestimate or overestimate screen time, and estimates of shared reading can also be affected by recall and social desirability. The study’s modelling choices reduce some statistical problems, but they cannot remove measurement error from the underlying reports.
Retention across waves was high but not complete, at roughly the mid-80% range. Attrition can matter if families who remain in a longitudinal study systematically differ from those who leave. The Taiwanese context is another limitation. Family routines, educational expectations, childcare systems and digital-media practices differ across societies, so the size of the relationship should not automatically be assumed to apply elsewhere.
What the findings mean for families and early-childhood programmes
The study does not provide a precise prescription for how many minutes families should read or use screens. Instead, it suggests that interventions may be more realistic when they address the two behaviours together.
A programme focused only on reducing screen exposure leaves a practical question unanswered: what replaces that time? Shared reading is one possible substitute that brings its own opportunities for conversation, vocabulary exposure, joint attention and caregiver-child interaction. Conversely, programmes promoting reading may work better when they also consider the routines in which screens currently serve a useful function for families.
This matters because screens are not simply entertainment devices. Caregivers may use them while preparing meals, working, travelling or managing a tired child. Advice that ignores those constraints can be difficult to follow. The reciprocal pattern supports an approach centred on family routines rather than treating a single behaviour as an isolated problem.
Future research could strengthen the evidence by combining caregiver reports with objective device-use records, distinguishing educational and recreational content, observing the quality of shared reading, and testing interventions that deliberately change one routine to see whether the other responds. Cross-cultural replication would show whether the reciprocal relationship is similar in families with different childcare arrangements and media environments.
The broader lesson is about competing routines
The most useful contribution of the study is not a claim that books are simply good and screens are simply bad. It is evidence that two common preschool activities appear to be dynamically connected within the same child over time.
Across ages three, four and five, increases in shared reading relative to a child’s normal routine predicted lower later screen exposure, while increases in screen exposure predicted lower later shared reading. The associations were modest, but their reciprocal nature suggests that changing one part of family life may have consequences for the other.
For researchers and families alike, that shifts the question from whether screens or books matter independently to how everyday routines compete, reinforce one another and evolve together during early childhood.
Source Information
Study: Wang, X., Chen, D. & Li, D. Screen exposure and shared book reading: evidence from a random intercept cross-lagged panel model.
Journal: Scientific Reports
Published: 3 October 2026
DOI: 10.1038/s41598-026-73192-5
Study type: Longitudinal observational study using a random intercept cross-lagged panel model
Sample: 2,164 children from the Kids in Taiwan: National Longitudinal Study of Child Development and Care, assessed at 36, 48 and 60 months
