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

Abstract

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.

Infant sleep as a topic in healthcare guidance of parents, prenatally and the first 6 months after birth: a scoping review

“…Although highlighted safe sleep recommendations seem to be widely known and recommended, research shows that parents tend to form their own practice in their home environments [ 22 , 28 , 29 , 47 ]. This applies particularly to the sharing of the same bed surface.…”

“…The thematic focus of the review is identified as complex, involving many environmental, parental, and child factors, in addition to relations between different participants [ 16 , 22 ]. While working on the study protocol, we decided to use a framework adapted from a well-known transactional model of infant sleep to guide data extraction from each study and summarize topics and factors [ 16 ].…”

“…Existing safe infant sleep advice seems to be based on at least two strong paradigms [ 21 , 22 ]: the risk-elimination approach advocated by the American Academy of Pediatrics (AAP) and a risk-reducing, cultural, and neurobiological approach that addresses what is thought to be natural for human beings [ 23 , 24 ]. Advice and counseling must be relevant for parents and conveyed in a sensitive and understandable way, taking into consideration cultural differences [ 25 ].…”

Biologically normal sleep in the mother‐infant dyad

“…In WEIRD societies models of infant care became biomedicalized as a consequence of the reliance on statistical normalcy, that is, conceptualized as within the purview of medical experts who set the standards for what is considered “normal” and “healthy” sleep (Ball, 2008; Ball et al, 2019; McKenna et al, 2007; Tomori, 2014). Biological and evolutionary views on infant sleep norms entered the discourse only over the past 20 years, but are now beginning to gain traction with both parents and health practitioners, and with a small but growing group of pediatricians and infant sleep researchers (e.g., Barry, 2020; Mileva‐Seitz et al, 2017). This approach seeks to root guidance for parents in data related to human infant physiology and evolutionary expectations, rather than cultural norms that have shifted enormously in the last two centuries.…”

“…Pre‐natal fantasies of a baby sleeping soundly in his/her carefully prepared crib are rarely realized; yet unrealistic expectations are unintentionally reinforced by clinicians and well‐wishers; even strangers take an interest in whether new babies they encounter are “good,” (meaning sleeping “through the night”). The Western cultural obsession with infant sleep leads parents to wonder, sooner or later, whether their infant's sleep patterns are “normal,” what they could or should be doing differently, and whether something they are not doing (or buying) would help their baby to fall asleep more quickly, to sleep for longer, or more deeply, or through the night (Ball, 2020; Barry, 2020).…”