Researchers looked at toddlers aged 30 months to 36 months and found that depriving them of a single daily nap resulted in more anxiety, lower levels of joy and interest, and reduced problem-solving abilities.
"This study shows insufficient sleep in the form of missing a nap taxes the way toddlers express different feelings, and, over time, may shape their developing emotional brains and put them at risk for lifelong, mood-related problems," she explained.
The researchers videotaped the emotional expressions of toddlers while they worked on solvable and unsolvable picture puzzles on two different days. One day, the test was conducted an hour after the toddlers had their normal 90-minute daytime nap. On another day, the toddlers were deprived of their naps and tested an hour after their normal nap time.
When they were nap-deprived, the toddlers had a 34 percent decrease in positive emotional responses after completing the solvable puzzles, a 31 percent increase in negative emotional responses when they were unable to complete the unsolvable puzzles, and a 39 percent decrease in the expression of confusion when they tried to complete the unsolvable puzzles.
"Confusion is not bad - it's a complex emotion showing a child knows something does not add up," LeBourgeois noted. "When well-slept toddlers experience confusion, they are more likely to elicit help from others, which is a positive, adaptive response indicating they are cognitively engaged with their world."
Overall, according to the release, the study shows that missing a daytime nap may make it more difficult for toddlers to take full advantage of exciting and interesting experiences and to adapt to new frustrations.
"Just like good nutrition, adequate sleep is a basic need that gives children the best chance of getting what is most important from the people and things they experience each day.