The term ‘co-sleeping’ generally refers to infants sleeping with or near their mothers or parents on the same or different surfaces but at least close enough for participants to detect and respond to each other’s cues (Hewlett and Roulette, in Narvaez et al., 2014). Breast-feeding is functionally interdependent with co-sleeping because it makes breast-feeding a lot easier for mothers, including allowing them to get more sleep. Anthropologists have notes that co-sleeping is almost universal cross-culturally and has a deep phylogenetic history that is practiced by all the old-world monkeys and great apes. Co-sleeping facilitates breastfeeding and reduces risk for sudden infant death.

The human infant is born the most immature of all primates and lacks the ability to thermoregulate (keep warm) enough to sleep on their own. Co-sleeping among non-western cultures seems to occur because they value family bonds and interdependent relationships while western culture values the development of independence and self-reliance thus placing children in their own beds to promote these cultural ideals. House ecology plays a role (size of house) but this is viewed as being secondary. A classic study in Japan showed that it was a moral imperative to co-sleep rather than about spatial ecology (number of rooms in the house).

Aka hunter-gatherers living in the Central African Republic live in camps of 25-35 people (Hewlett and Roulette, in Narvaez et al., 2014). The foundational schema of their culture are autonomy, sharing and egalitarianism. One does not coerce or tell people what to do, including children. If an infant wants to play with a machete she is allowed to do so. Sharing of childcare is extensive – 90% of Aka mothers report that other women nursed their young babies. Physical and emotional closeness are very important to the Aka – when they sit in camp, they are usually touching somebody else. Forager infants are held 91% of the day (compared with farmer infants who were held 54% of the day). Forager 2, 3 and 4 years olds are held 44%, 27% and 8% of day time hours (18%, 2% and 0% for farmers). In two studies the importance of emotional proximity was illustrated. Hunter-gather toddlers were more likely to have conflict over staying close to older juveniles, while farmer toddlers were more likely to have conflict with older juveniles over competition for objects or over the juvenile hitting the toddler, something which never happened among hunter-gather toddlers. This shows the early acquisition and manifestation of cultural values. Aka children do what they want whereas farmer children are controlled by adults and older siblings.

One study showed Aka 3-4 month-olds took the breast on their own in 58% of feeding bouts whereas farmer children did this only 2% of the time – farmer mothers decided when to nurse, not the infant (Hewlett and Roulette, in Narvaez et al., 2014). Hunter-gather mothers said the child decided when to wean whereas farmer mothers decided when weaning occurred and often used dramatic techniques. Aka Aunts, grandmothers and even fathers offered the infant their breast. In early infancy Aka mothers provide the most care but infants are held by many others, the latter constituting more holding than holding by the mother. When asked why the child slept where they did the Aka replied that this is where the child wants to sleep. Infants often sleep between the mother and father who wrap their legs over the infant to keep them warm.

How do children learn to co-operate and share so readily in hunter-gather cultures? (Hewlett and Roulette, in Narvaez et al., 2014). The authors suggest that regular co-sleeping throughout the juvenile phase led to theory of mind, empathy and the trust needed for co-operation and sharing beyond the nuclear family. The authors argue that co-sleeping is the norm throughout human history and so should not be considered deviant or unusual today. At a minimum, human bodies and minds are adapted to co-sleeping beyond weaning. Bed sharing likely enhances trust of self and trust of others (feeling safe and secure while asleep). Co-sleeping was partly a safety measure against predation and so sleeping alone reduced children’s chance of survival. Thus, our biology may still associate sleeping alone with danger. Co-sleeping develops intimate knowledge of those with whom one sleeps and may be a way for parents to spend more time with their children.

Co-sleeping is “a context of care, a foundation for socialisation, and an aspect of our developmental niche” (Middlemiss, in Narvaez et al, 2014, p.164). Increases in wealth leads to more space which means less contact between mothers, fathers and their children. In the western context co sleeping beliefs move away from the ‘context of care’ to seeing it as a practice that undermines the development of needed skills. This shifts away from the importance of developing shared, co-operative trusting interactions – the developmental niche of children that sees these as forming the foundation of healthy biological and emotional growth. This is lost in the pursuit of ‘independent functioning’.

In western culture, co-sleeping is seen as intrusive, maladaptive, dangerous and based on an inability to set limits. The basis for these critiques does not consider the importance of caregiver-child interactions for socioemotional development. In thinking about sleep arrangements, the importance of close, responsive interactions are not considered. This is based on the desire for infant independent regulation but science shows early non-responsiveness is linked with diminished positive social and emotional health later in life. Parents are left confused and distressed with lack of shared sleep and responsiveness at night-time where there is a conflict between the ‘normative drive’ to be responsive to build trust and co-operativeness in a child and “mandates to encourage self-settling sleep at extraordinarily young ages” (p.165). This conflict between caring and the cultural message to stay distant creates stress. There is little consideration of how this cultural trend developed and less in considering the cost of it. But there are strong indicators that these practices may constrain interactions that build attachment which underlies the development of children’s social and emotional strengths. This may have a significant cost to our children’s and societies well-being.