Washington: A new longitudinal study, carried out by researchers at the University of Montreal and the University of Minnesota, has revealed that babies who get most of their sleep during the night-time develop better skills than infants who sleep mostly during the day.
The study involved 60 Canadian children, at ages 1, 1-1/2 and 2, and analysed the effects of infants` sleep on executive functioning.
In children, executive functioning includes the ability of controlling impulses, of remembering things and of showing mental flexibility.
Even though researchers knew that executive functioning develops rapidly between a child`s first and sixth birthday, they had no idea why there were some kids who are better than others at acquiring these skills.
When the children were one year old and one and a half year old, their mothers filled out three-day sleep diaries, noting hour-by-hour patterns, nighttime wakings and daytime naps.
Six months later, the researchers assessed the children`s executive functioning skills, and found that kids who slept mostly during the night had better results at the test tasks, especially those involving impulse controls.
They then considered factors like the parents` income and education, and the infants` general cognitive skills, and concluded that the relationship between the children`s skills and sleep remained unchanged.
The overall sleeping time and the number of times the children woke up at night had no connection to their executive functioning skills.
"We found that infants` sleep is associated with cognitive functions that depend on brain structures that develop rapidly in the first two years of life," said Annie Bernier, professor of psychology at the University of Montreal.
"This may imply that good night-time sleep in infancy sets in motion a cascade of neural effects that has implications for later executive skills.
These findings add to previous research with school-age children, which has shown that sleep plays a role in the development of higher-order cognitive functions that involve the brain`s prefrontal cortex," she added.
The research is published in the November/December 2010 issue of the journal Child Development.