 A child's awareness of time develops during childhood, when the child's attention and short-term memory capacities form — this developmental process is thought to be dependent on the slow maturation of the prefrontal cortex and hippocampus.One day would be approximately 1/4,000 of the life of an 11-year-old, but approximately 1/20,000 of the life of a 55-year-old.This helps to explain why a random, ordinary day may therefore appear longer for a young child than an adult.