The effects of social distancing policies on children's language development, sleep and executive functions.

The environments children grow up in heavily influence key elements of cognitive development such as language and executive functions, which in turn associate with later educational and occupational attainment as well as health and wellbeing (1-8). The COVID-19 pandemic is a unique, once-in-a-lifetime situation that has dramatically changed the daily lives of millions of families. Several environmental factors likely to be affected by quarantine measures (such as sleep (9-17), parenting style and social interactions (18-22), screen use (23-27), and outdoor activities/exercise (28)) are known predictors of language and executive function development. The proposed study will follow up a UK-wide cohort of 600 children aged 8 to 36 months of age, enrolled in an online study at the onset of social distancing measures, to capture changes in key environmental variables and measure their impact on children's vocabulary size and executive function. Using sophisticated analyses on a large and diverse sample, we will examine the role of each factor on children's cognitive abilities. At this time of unforeseen and ongoing change, it is imperative to understand the impacts of the lockdown on cognition during a critical period for development (0 to 3 years of age), and then find strategies to minimise disruption to this cohort. Our findings will identify approaches that mitigate the temporary loss of formal early years' education, identify those groups most at risk of adverse consequences, and inform policy on how to remediate the negative impacts of lockdown post-COVID-19.