Children who have enough sleep and go to bed at regular times do better at school. Researchers from SRI International, an independent American research institute studied 8,000 four-year-old children. They asked their parents about their children's bed times when they were nine months old and four years old and carried out developmental assessments when they were four. Having a regular bedtime was the most constant predictor of positive developmental outcomes. Scores for receptive and expressive language, phonological awareness, literacy and numeracy were all higher in children who had rules about their bed times. It is recommended that children this age get 11 hours sleep a night.
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