Nurturing Your Infant

Attachment and Infant Sleep
Miranda Barone, Ph.D.
California State University, Long Beach

Attachment theory was originally conceptualized by John Bowlby as an organized behavioral system with "set goals" of maintaining proximity to a primary caregiver to ensure protection from dangers and promote security and survival. During the first few months of life, infants can sleep up to 60% of a 24 hour day, including naps and small wakings. Although Bowlby may not have directly addressed issues of infant sleep, it is doubtful he would have conceptualized attachment behavior as occurring only during a smaller percentage of the day. Attachment is a process that is not turned off during sleep. Previous reliance on research conducted on infants sleeping in solitary situations has been insufficient to our basic understanding of infant sleep organization and the physical and psychological needs of infants during what is a large proportion of their day. Infants need to feel safe and secure even while sleeping and that security may only be experienced during cosleeping with a parent.

The need for parents to understand infant sleep is evidenced by the multitude of advice that exists on helping infants sleep better through the night. The advice that has been provided, however, contains Western cultural biases promoting solitary sleep conditions for infants. The first question almost all new parents are asked about their infant is does he sleep through the night? Of course, it is assumed that the infant is sleeping alone and, hopefully, in a very expensive designer crib. This puts tremendous pressure and unrealistic expectations on parents to answer yes. Anything short of a yes response would promote feeling of failure in parenting style and the horror of suspecting their baby has a sleep problem. But what is normal infant sleep? Should infants be expected to sleep through the night? Are they biologically prepared to sleep in a solitary situation all through the night? What is a normal sleep situation for infants?

What Constitutes Normal Sleeping Arrangements

Researchers of infant sleep have relied on Western cultural values of pushing infants to independence, often times beginning with solitary sleeping arrangements. Without asking why one arrangement should be valued over the other, researchers have not developed an understanding of an infant's biological needs which tend to be social in nature due to their extreme altriciality (helplessness at birth), neurological immaturity and slow maturation. In fact, over 70% of the world's populations do consider sleep a social event (Barry and Paxon, 1971). In non-western cultures, individuals often sleep with family members, if not in the same bed, within close proximity. For 70% of the world's population, leaving an infant alone to sleep is not a normal routine. These statistics, and the relative recency of separate sleeping arrangements for parents and infants, raises questions about the development of such a socially constructed practice, and the need to understand what is occurring in solitary and cosleeping condions.

Solitary nocturnal, a Western cultural creation, has led many parents to seek expert advice on how to get their infant to sleep through the night. The advice usually reflects strong cultural norms and biases regarding parent and infant sleeping arrangements during the night. Most of the advice includes a cautionary note about allowing an infant to sleep in a parent's bed, warning of serious consequences that may develop from such a routine. Until recently, a solitary sleeping environment for infants was accepted without question. This advice, however, was against the background of a paucity of research conducted in the area of infant sleep. A growing body of literature on parent-infant cosleeping, or bedsharing, questioning the practice of solitary infant sleep environments, has found evidence of several benefits afforded to both mother and infant in cosleeping conditions (see McKenna, 1996). This research has provided scientific information to justify reevaluating assumptions underlying prevailing infant sleep research. It may be that many of the sleep problems that parents report and experts write about are actually the result of rigid and unreasonable cultural expectations that ignore biological facts and infant needs. Today, the effects of parent-infant cosleeping have become a source of vigorous debate among parents, child-care experts, and researchers. During the early part of this century, childcare practices were highly influenced by the psychoanalytic and behavioristic perspectives. The underlying principles of both approaches would certainly rule out cosleeping as a caregiving norm. The psychoanalytic perspective on infant development placed a great deal of emphasis on infantile sexuality and childhood urges for erotic pleasure. Close contact between a child and mother was thought to over gratify these urges for erotic pleasure, thereby contributing to later intrapersonal conflicts and neurotic and moral anxiety. Behaviorists disagreed with the mentalistic approaches of the psychoanalysts, and were able to demonstrate that learned behavior could be shaped via classical and operant conditioning. Many of the current techniques taught to parents for infant sleep training are based on operant conditioning. For example, Ferber, although not a behaviorist, recommends that parents teach an infant to sleep alone by a process of graduated extinction, not responding to, and thus, not reinforcing an infant's crying behavior. Unfortunately it cannot be ascertained that children learn to sleep alone, as some of the experts claim. It is quite plausible that they may be learning not to expect their mothers to comfort them when they are distressed. Both the psychoanalytic and the behavioristic perspectives have set the tone for many early childcare books. These earlier perspectives established a focus of inquiry based primarily on Western social norms of independence and autonomy. Many experts expressed concern that cosleeping disturbed the normal process of individuation and independence, violated the marital relationship, and lead to generalized anxiety and social immaturity. There is no research to support these erroneous conclusions. This Western focus of inquiry may have distracted researchers from examining what may actually occur between the mother-infant interaction during sleep.

Should infants be expected to sleep through the night? Are they biologically prepared to sleep in a solitary situation all through the night?

Only recently has an alternate view of infant sleep been proposed in Western research. That view acknowledges the infant's extreme altriciality and constant need for close proximity to a primary caregiver. These more recent psychological perspectives have provided greater insight into the mother-child relationship by incorporating Attachment Theory. Bowlby (1969) stated that the problem with most research in psychology was the attempt to explain the functioning of personality in terms of ontogenesis - from an end product backwards. He promoted the idea of using primary data observations to understand how young children behave in defined situation. This led contemporary infant sleep researchers to the questions of how do infants sleep in their own natural environment and what is the natural environment for infants to sleep. Bowlby stated that we need to look to the Environment of Evolutionary Adaptedness (EEA), the environment to which a species is adapted, to understand functional properties of certain behaviors. The functional properties of organisms arise by the process of evolution by natural selection over thousands of generations. Humans have not changed much in the past 10,000 years. Bowlby's principle assumption was that during humankind's evolution, infants remained in close contact with their mother or primary caregiver, day and night. At birth the human infant is the least neurologically mature primate and the most reliant on physiological regulation by its caregiver for the longest period of time. Removing an infant from this safe and secure environment may not be in the best interest of the infant. Biological data indicates that infant and maternal sleep physiologies are entwined in adaptive ways. For the extremely neurologically immature human infant, social care is synonymous with physiological care or regulation. The conclusion is that our Western culturally favored patterns of child care, which include solitary infant sleep, have changed much faster than does an infant's biology.

James McKenna, Sarah Mosko and Chris Richard conducted a series of studies utilizing this conceptual framework when studying the risks associated with Sudden Infant Death Syndrome (SIDS). They proposed that arousal deficits, especially during deep consolidated or prolonged sleep bouts, such as during stages 3-4, may play an important role in the etiology of SIDS. Unfortunately, prolonged bouts of nocturnal sleep for infants are idealized by Western society. Paradoxically, they found that cosleeping infants, who experienced more frequent night wakings, had fewer apneas. These studies suggest that normal infant sleep should not be consolidated such that it includes prolonged deep sleep bouts. Arousals during long bouts of nocturnal sleep may be helpful, if not essential for an infant. McKenna also found that cosleeping promoted breastfeeding, which is generally accepted as advantageous for infant development and protective against SIDS. Recently the American Academy of Pediatrics revised recommendations regarding breastfeeding from six months to at least one year. They also recommended keeping an infant in close proximity. It is well established that breastfed babies require more frequent feeding because breast milk is more easily and rapidly digested. Keeping the infant in a cosleeping situation is clearly advantageous because they still tend to be hungry during the night! In my own research, I observed over two thousand hours of mothers and infants cosleeping and sleeping separately. Mothers in solitary conditions were observed to sleep less as they reached full awakenings when they got up and went to another room to feed and change their babies. Under solitary night conditions, infants revealed increased continuous large limb movements, small limb movements, head rotations, vocalization, crying, self-soothing behaviors, and spontaneous startles (Barone, 2001). The increase in physical activity tended to be clustered, such that infants in solitary conditions revealed more prolonged bouts of activity than infants in cosleeping conditions. Restless sleep, increased crying, and missed feedings can lead to increased distress, which cannot be advantageous for a rapidly developing infant. Some research indicates that early stress due to separation causes changes in infant brains that makes future adults more susceptible to stress in their lives. Therefore, we should not expect infants to sleep through the night because they are not biologically prepared to sleep in a solitary situation all through the night. The normal sleep environment for infants must be a cosleeping situation with a parent. Infants cannot physically care for themselves, nor do they have sophisticated and developed cognitive abilities to understand why they are alone. Infants who cosleep tend to be physically calmer when sleeping close to their mothers. Certainly, every new parent has experienced being aroused from a deep slumber by the sound of their infant crying. Infants communicate their need to be close to a parent by crying. Research indicates that the majority of infants who cry at night sleep in a solitary situation. Instead of letting infants cry, Western parents should keep their babies close, console them when they cry, and allow them to cosleep, where they'll feel safe and secure. Attachment research has found that children who feel safe and secure as a children tend to be more well adjusted, independent, and caring adults.


Barone, M (2001) Mother-Infant Sleep Behaviors In Solitary And Bedsharing Conditions. Dissertation Abstracts.

Barry, H. III and Paxson, L. H. (1971). Infancy and early childhood: Cross-cultural codes. Ethology, 10, 466-508.

Bowlby, J. (1969). Attachment. New York: Basic Books.

McKenna, J. (1990a). Evolution and sudden infant death syndrome (SIDS)
Part 1: Infant responsivity in response to parental contact. Human Nature, 1(2), 145-177.

McKenna, J. (1990b). Evolution and sudden infant death syndrome (SIDS)
Part 2. Human Nature, 1(2), 179-206.

McKenna, J. (1996). Sudden infant death syndrome in cross-cultural perspective: Is infant-parent co-sleeping protective? Annual Review of Anthropology, 25, 201-216.

McKenna, J. and Mosko, S. (1990). Evolution and sudden infant death syndrome (SIDS) Part 3: Infant arousal and parent-infant co-sleeping. Human Nature, 1(2), 291-324.

McKenna, J. and Mosko, S. (1993). Evolution and infant sleep: An experimental study of infant-parent co-sleeping and its implications for SIDS. Acta Paediatrica Supplement, 389, 31-36.

McKenna, J., Mosko S., and Richard, C. (1997). Bedsharing promotes breastfeeding. Pediatrics, 100(2), 215-219.