Saturday, March 28, 2009

Co-sleeping: It's a mammal thing

In a web article at, posted in February 2009, pediatrician Sydney Spiesel discusses the pros of cons of allowing infants to sleep with their parents. The overall tone of the article is to discourage parents from allowing infants to sleep with them; Dr. Spiesel's conclusion, based on research reported in the journal Pediatrics, is summed up as follows:
Not only are there no good data to support [alleged benefits of co-sleeping], but a new study supports what most pediatricians have been saying all along: There is substantial risk in infant-parent bed sharing, and parents should be aware of this risk before bringing babies to bed to sleep with them.
There are several points to be made about this from an anthropological perspective:
  • Humans are mammals. All or nearly all (I can't think of any counter-examples) mammalian young sleep in contact with their mothers and/or other members of the family group. This allows them to nurse on demand, keeps them warm, and helps protect them from potential predators. If co-sleeping were significantly risky, mammals probably would have gone the way of the dinosaurs, or evolved into something else.

  • In most human cultures, infants co-sleep with their parents. Most of the time, there's no other choice; there's simply no other place for them to sleep. And again, if co-sleeping carried a significant risk for humans, we likely wouldn't be here to discuss it.

  • The idea that infants should sleep apart from their parents is a value specific to some cultures, not a cultural universal. Where this value is strong, as in the USA, Independence Training is implicated. This value is so strong in US culture that infants are even given their own rooms, rooms that are prepared for them (e.g. painted pink or blue, etc.) before they are born.

  • Some infant deaths that appear to be caused by co-sleeping are actually instances of neglect, abuse, or worse. As a colleague points out, parents may be too whacked out on alcohol or other drugs to have a normal level of awareness. And more than a few such cases are instances of outright infanticide that are reported as accidents.
So, from the evolutionary and cross-cultural perspective of anthropology, infant co-sleeping (like nursing in public) appears to be the usual, or as we say in linguistics, unmarked, practice. And judging from a real weighing of the benefits and risks, co-sleeping is better for infants and parents than not co-sleeping. Arguments to the contrary are generally informed more by ethnocentrism than by truly sound research.

For a good summary of this issue by an anthropologist who specializes in research on this topic, see James McKenna's article Cosleeping and Biological Imperatives: Why Human Babies Do Not and Should Not Sleep Alone.


  1. When I was pregnant, I read up on this because I planned on co-sleeping. I also read (can't remember where now) that co-sleeping babies wind up having the same sleep cycle as their mom and that this is good for them somehow. I don't remember exactly why but the argument was that it's actually safer for them.

    I know that on a practical level, it helped for feeding. Since I was nursing him, we didn't have to get up for feeding. I could even leave all the necessary supplies near the bed and change his diaper right there if needed.

  2. "All or nearly all (I can't think of any counter-examples) mammalian young sleep in contact with their mothers and/or other members of the family group."

    Tree shrew mothers do not sleep with their young.

    Peter Apps

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