Child development: Traffic noise at schools may hinder memory and attentiveness

Students who were exposed to the highest level of outdoor noise pollution while at school showed slower improvements in memory and attentiveness

By Carissa Wong

Road traffic noise outside schools may impair the development of a child’s attention span and short-term memory.­

Previous studies have shown that noise pollution from road traffic can disrupt sleep and increase stress in adults. Meanwhile, local aircraft noise has been shown to reduce academic performance and reading comprehension in children. However, it wasn’t known whether road traffic noise outside schools impacts cognitive development in children.

To learn more, Maria Foraster at the Barcelona Institute for Global Health and her colleagues recruited 2680 children aged 7 to 10 from 38 schools throughout Barcelona.

The researchers stood in a certain point of each school and measured the noise coming in from the outside before lessons began. This was repeated six months later to calculate an average baseline level of noise pollution at each site.

Using online cognitive tests, the team tested the children’s short-term memory and attentiveness every three months for a year.

The children in schools with higher average indoor noise levels – defined as above 30 decibels, about the volume of whispering – saw a slower improvement in attentiveness, measured by comparing their performance on tests at the start of the year with those at the end of the year.

Further analysis revealed that a greater level of fluctuation in indoor noise levels was more strongly associated with a slower improvement of both working memory and attentiveness, compared with more consistent noise levels.

“This study has broken new ground in studies of environmental noise and children’s learning,” says Stephen Stansfeld at Queen Mary University of London, who wasn’t involved in the research. Children may be more likely to notice fluctuating noise levels, he says. “Attention to noise may interfere with their attention to other tasks related to normal cognitive development.”

The analysis accounted for levels of local air pollution, as well as the socioeconomic status, age and sex of the participants.

“They have adjusted for a very wide range of potential confounding factors in their analyses, thus ruling out many other explanations,” says Stansfeld.

Nevertheless, further research with a more diverse group of participants is required. For example, “the sample of families involved in this study was better educated than the general population”, he says.

Journal reference: PLoS Medicine, DOI: https://doi.org/10.1371/journal.pmed.1004001