A new study has said that children in households with bedtime rules turn out to be more intelligent.
The study, conducted by scientists at SRI International, an independent, non-profit research institute in California, has shown that youngsters who had regular bedtimes were better at languages, reading and maths than those than did not.
Those who went to bed earlier than most were even more likely to pick things up more quickly.
The research centered on developmental outcomes of children aged four.
In the largest study of its kind to date, the team used a sample of around 8,000 kids who completed a developmental assessment at four years of age.
The analysis also included information on bedtimes from parent phone interviews when their child was nine months old and again when their child was four.
The findings indicated having a regular bedtime was the most consistent predictor of positive developmental outcomes.
Scores for receptive and expressive language, phonological awareness, literacy and early maths abilities were higher in children whose parents reported having rules about what time their child goes to bed.
Meanwhile having an earlier bedtime was predictive of higher scores for most developmental measures.
"Getting parents to set bedtime routines can be an important way to make a significant impact on children's emergent literacy and language skills. Pediatricians can easily promote regular bedtimes with parents and children, behaviours which in turn lead to healthy sleep," Dr Erika Gaylor, who led the study, said.
Gaylor recommended parents set an appropriate time for their child to go to bed so they get sufficient levels of sleep.
The study has been presented in San Antonio, Texas, at SLEEP 2010, the 24th annual meeting of the Associated Professional Sleep Societies LLC.