Kids in their early elementary school age years are very curious, want to explore, invent, create and conquer. (thespruce.com)
It has been found that sleep problems in infancy can indeed carry on into the preschool and school age years if not managed early in life. (day2dayparenting.com)
Subsequently, the capacity for effortful control increases markedly in the preschool years and may continue to develop into adulthood.2 However, despite the progressive development due to maturation, EC appears to show within - subject stability from toddlerhood through preschool and into early school age years.3 (child-encyclopedia.com)