This study aims to determine how nighttime screen time affects attention, subjectively perceived school performance, and actual performance in the form of grades. For this study, online surveys were conducted with 384 parent-child pairs. Parents and children aged 10-14 provided information on children's nighttime smartphone use, subjectively perceived attention ability, and children's current school performance at two different time points.

The study's findings primarily indicate that nighttime smartphone usage has a negative impact on the cognitive attention perceived by parents of 10-14-year-old children and teenagers. The development of attention deficits often carries the risk of negatively affecting school performance, both subjectively and through objective measurements. Furthermore, the study also revealed that nighttime smartphone usage can have a positive impact on subjective school performance.

The general presence and extensive use of smartphones are characteristic of today's society, with the smartphone becoming an indispensable daily device for many people. A widespread practice, especially among teenagers, is the use of smartphones at night just before going to bed. Many experts advise against using it in bed, as some users usually fall asleep (too) late or could be woken up by the nightly notifications. It is also important to note that the bed should be an environment that encourages regeneration and preparation for sleep. Smartphone use can disturb this phase, as it has been shown to trigger psychological and physiological activity. In addition, the intense bright light emitted by smartphone screens can disrupt the rhythm of sleep.

Communication scientists have been researching for some time how young people accumulate screen time and specifically how much of it is spent during the night hours. Especially with regard to the development, physical and mental health and ultimately also the school performance of children and adolescents, sleep and its quality prove to be of essential importance. Researchers have even stated in the past that symptoms of attention deficit disorder can hardly be differentiated from symptoms of sleep deprivation.

Lack of sleep leads to attention deficits

Some findings already suggest that the lack of sleep causes concentration and attention problems for young people. Despite the topics' relevance most research on smartphone use in context of school performance is based on cross-sectional studies.

The study by communication scientists Anja Stevic, Desirée Schmuck, Marina F. Thomas, Kathrin Karsay, and Jörg Matthes of the University of Vienna aims to close this research gap. As part of their research project, they collected data from 384 parent-child pairs (with children aged 10-14) to relate nighttime smartphone use to parent-reported attention problems and subjectively perceived and actual school achievement.

The longitudinal study collected data in two waves from kids and teenagers aged 10-14 with the support of one parent each. The study was part of a bigger project of child-parent surveys about smartphone use. It was conducted in Germany at two points in September 2018 and later in February 2019. The quota sample was composed on the basis of age and gender of the parents. The primary aim of the research was the child's smartphone use after going to bed, the attentional problems, the subjectively perceived school performance and the actual grades in the subjects German, English, and Mathematics.

Social media and school performance: A surprising finding?

The authors of the study demonstrated a negative correlation between children's nighttime smartphone use and their attentional problems that parents noticed in their children. According to the researchers, this is not surprising, as chatting, posting, and commenting at night (for example on social networks like Facebook and Snapchat, which are used particularly often in the evening and at night) delays or even interrupts sleep. In particular, children and adolescents who use a range of different social media platforms tend to consume these media to a greater extent and for longer periods of time.

The result of the study shows that delayed or disturbed sleep due to smartphone use has a negative impact on cognitive development and concentration over a longer period of time. The attentional problems might lead to a decline in subjectively perceived school performance. Nevertheless, the analysis of the results shows a positive correlation between the children's nighttime smartphone use and the actual school performance achieved over time. Thus, smartphone use in the evening was associated with higher school performance after four months. One explanation could be that the smartphone is used in the evening to share school-related content. However, as the research team points out, media consumption can have different consequences on different children and adolescents. Study author Anja Stevic therefore concludes that "the findings highlight the importance of regulating children's nighttime smartphone use in order to mitigate its potentially negative consequences on the attention and academic performance."

Conclusion: Nighttime smartphone use disrupts attention, not necessarily the school performance

In summary, the long-term study was able to demonstrate a direct, positive correlation between nighttime smartphone use and the achieved school performance. Nevertheless, it was also shown that the children's use of smartphones at night over a longer period of time can have a harmful effect on the cognitive ability to pay attention during the day. The subjective perception of school performance suffered accordingly, as the lack of sufficient recovery time is associated with attention problems. It is questionable whether these results apply equally to all children or are influenced by other individual or school-related factors. Accordingly, it would be interesting to deepen the research by taking personal characteristics into account, such as an ADHD diagnosis, among others. Anja Stevic concludes by stressing the importance of developing effective interventions "to optimize children's smartphone use at night".