What Is "Normal" Infant Sleep? Why We Still Do Not Know

Psychol Rep. 2021 Apr;124(2):651-692. doi: 10.1177/0033294120909447. Epub 2020 Mar 5.


The human need for sleep is universal and unquestioned; however, humans vary in their sleep needs according to age, individual differences, as well as cultural and social norms and practices. Therefore, what is "normal" in infant sleep and the development of sleep architecture in humans is highly dependent on biological and sociocultural variables as well as socially constructed assumptions about what infant sleep "should" look like. This paper uses a multidisciplinary approach to review papers from fields including pediatrics, anthropology, psychology, medicine, and sociology to understand "normal" infant sleep. Because human culture and behavioral practice changes much more quickly than evolved human biology, and because human evolutionary history occurred in the context of breastfeeding and cosleeping, new work in the field of infant sleep architecture development would benefit from a multidisciplinary approach. To come to a consensus about what is "normal" infant sleep, researchers must agree on underlying basic assumptions of infant sleep from which to ask question and interpret findings.

Keywords: Infant sleep; bedsharing; cosleeping; normal sleep; sleep recommendations; well-being.

Publication types

  • Review

MeSH terms

  • Biological Evolution
  • Breast Feeding
  • Humans
  • Infant
  • Sleep / physiology*