An article in the November/December issue of Child Development shows a connection between nighttime sleep for babies and their skill at certain tests of cognitive function.
Researchers from the University of Minnesota and the University of Montreal tracked the sleep patterns of toddlers. At 12 and 18 months, they asked parents to keep a diary of the baby’s sleep habits at 30-minute intervals around the clock (logging naps and night wakings). At 18 and 26 months, they gave the little subjects some baby brain challenges.
Here’s what they found when it comes to sleep and smarts:
The ones who slept more during the night (between 7 p.m. and 7 a.m.) did better on the tests than those who might have had the same amount of total sleep, but got a greater percentage of it during the day. In other words, nighttime sleep was more critical than naps. The researchers say the longer the nighttime stretch, the better the results.
The babies did tests of “executive function” which is the ability to hold information in working memory, control impulses, and make thought-out decisions (at 2 years old this is of course a work in progress). For example, in one test a researcher put a sticker in one of three pots, covered them with a blanket, and then asked the toddler to choose which contained the sticker.
Granted, this is a small study, but it resonates with earlier findings that sleep has a big impact on our executive functioning during the day — our ability to retain and work with information, and make sense of our surroundings. Same goes for babies.
I think it’s interesting that the total amount of sleep didn’t matter as much as the stretch of nighttime sleep that the babies had. If it holds up to further scrutiny, it means that catching up on nighttime sleep with a big long nap doesn’t quite add up. Nighttime sleep and naps are managed by different brain circuits and circadian rhythms, so it makes sense that it doesn’t just all go into one account — you can’t just transfer hours from your daytime to nighttime account.
Remember, though, all babies wake up during the night (just like most of us do). Some just know how to put themselves back to sleep. This is an argument for keeping to early bedtimes so that our little ones are getting their nighttime dose of zzz’s.
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