From Science Daily: 

The study shows toddlers between 2 and a half and 3 years old who miss only a single daily nap show more anxiety, less joy and interest and a poorer understanding of how to solve problems, said CU-Boulder Assistant Professor Monique LeBourgeois, who led the study. The results indicate insufficient sleep alters the facial expressions of toddlers — exciting events are responded to less positively and frustrating events are responded to more negatively, she said.

 “Many young children today are not getting enough sleep, and for toddlers, daytime naps are one way of making sure their ‘sleep tanks’ are set to full each day,” she said. “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.”

This assertion is perfectly intuitive to parents and professionals who work with toddlers, but researchers manufactured the circumstances to observe this phenomenon for themselves: 

 In the study, the toddlers’ faces were videotaped while they performed “kid-friendly” picture puzzles, including those of farm animals, sea creatures and insects. One puzzle each child worked had all of the correct pieces, which gave him or her the opportunity to experience and express positive emotion, she said. A second puzzle had a “wrong” piece and therefore was frustrating to the toddlers in the study because it was unsolvable.

Facial expressions of the toddlers were coded on a second-by-second basis for emotions like joy, interest, excitement, sadness, anger, anxiety, disgust, shame and confusion.

The study showed nap-deprived toddlers completing the solvable puzzles had a 34 percent decrease in positive emotional responses compared to the same children completing similar puzzles after their usual midday naps. The study also showed a 31 percent increase in negative emotional responses of nap-deprived toddlers when they attempted to complete unsolvable puzzles when compared with puzzle-solving attempts after they had napped.

In addition, the study found a 39 percent decrease in the expression of “confusion” when nap-deprived toddlers attempted to put together unsolvable puzzles. “Confusion is not bad — it’s a complex emotion showing a child knows something does not add up,” said LeBourgeois. “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.”

(…) 

 “A sleepy child in a classroom or daycare environment may not be able to engage with others and benefit from positive interactions,” she said. “Their coping skills decrease and they may be more prone to tantrums or frustration, which would affect how other children and adults interact with them. This study shows that missing even a single nap causes them to be less positive, more negative and have decreased cognitive engagement.”

They’re currently recruiting families for a study to determine the potential impact on cognitive ability and executive function. 

With the high frequency of sleep disturbances in kids with autism and sensory processing disorders, this suggests another layer of complexity to consider in our assessment and intervention. 

Read the article here.