Do Animals Have Babysitters? An Important Aspect of Human Child Care

A recent book by the anthropologist Sarah Hrdy (“Mothers and Others: The Evolutionary Origins of Mutual Understanding”, Harvard University Press, 2009), describes some important differences between the great apes and human beings in hunter-gatherer groups. Apes and humans are noticeably different in their reproductive and infant-care behaviors, and Hrdy proposes that these differences are important for our understanding of human development. Among the great apes, females give birth only every 6 to 8 years. Hunter-gatherer women usually give birth every 3 or 4 years. Yet apes mature more quickly than humans, so the ape big brother or big sister is almost an adult by the time the next infant is born, while the human child is still very much in need of adult care when the next baby comes. The mother ape invests many years’ work in bringing one offspring near to maturity before taking on the next, but the human may have several children who simultaneously require a great deal of adult nurturance and supervision. Human children particularly need the kind of personal attention that fosters language development, or they will not grow up to be functioning members of their group.

How is this apparently paradoxical situation to be understood? Sarah Hrdy suggests that one very big difference between humans and great apes lies in the number of caregivers each infant has. Ape mothers do not like other apes to so much as touch their young infants. Although other apes play with and help the juvenile apes as they get older, the mother is pretty much on her own in early infant care. Not so with human beings, however. Human mothers allow and even encourage familiar adults to be in contact with their babies. Those adults can and do provide important aspects of care-- not just feeding and cleaning, but the social interactions, gestures, and sounds that contribute to development of communication and speech. In the evolutionary development of our species, Hrdy believes, there were advantages for babies who were good at engaging with adults and getting cared for. Skill at understanding what other people felt and intended would also be advantageous. Those babies would be more likely to survive, grow to maturity, and reproduce, passing on their genetic material and the behavior traits associated with it. Those useful traits would be more important for humans, who might depend on many adults for care, than for apes who initially were cared for by their mothers alone.

It’s interesting to speculate on whether attachment-- the strong preference of humans for staying near familiar people at times of threat-- would also have emerged from having a mother who would tolerate other caregivers for her baby. A toddler who was very engaging might be likely to approach and communicate with strangers, who might then take the baby away-- unless internal attachment processes made it less likely that the child would approach completely unfamiliar people. A baby who was jealously guarded by its mother, as occurs among the great apes, would not need attachment processes to keep it near the family; the mother would do this job. Although attachment is often thought of as the “invisible playpen” that would have kept our ancestors’ babies out of danger from fire and wild animals, we see another important dimension when we realize that the babies’ ability to get attention from adults might have put them in danger of kidnapping or death from enemy humans. If they could crawl or toddle, but did not have the emotional attachment that would warn them away from strangers, they might not live to grow up; when they became mobile, the emergence of attachment and stranger anxiety would keep them safer.

Although social interaction, communication, and forms of attachment occur in species other than our own, it’s not necessarily correct to assume that any of those behaviors is the same in every species. I recently received a journal reviewer’s comment that referred to attachment as “transspecific” (occurring across species). Although that is true, it’s less correct to assume that attachment is “panspecific” (occurring in all species in the same way). Some behaviors of human and animal babies seem so parallel that we tend to think of them as identical when they may not be so. But no human baby exists without adult caregivers, and few animal babies can. That means that in order to understand parallels between humans and animals, we may need to look at adult caregiving behavior as well as at the babies’ own actions. Humans use babysitters, animals don’t--- and many other differences may follow from those facts.