If you are an orangutan, you don’t get any help raising a child. All orangutan mothers are single mothers, and in addition to lacking a helpful spouse, they lack any sort of family or neighborly assistance. They’re the sole providers for their offspring. And it shows.

It shows because the orangutan interbirth interval – the amount of time elapsed between births – is about 8 years. That’s how long it takes this socially-isolated, large-brained ape to raise a child to the point where she can safely begin the process all over again.

Large-brained babies are expensive. And if that’s true for orangutans, is doubly true for humans, whose babies have mega-brains. The average human infant spends over 60% of her energy budget on fueling her brain.

Yet humans don’t find it necessary to wait 8 years between having kids. And the reason is crystal clear. Human mothers have help.

Perhaps other relatives pitched in, too. A recent analysis of living hunter-gatherer groups suggests that adult brothers and sisters often live in the same foraging bands.

But the subsidies didn’t stop with any one helper. They couldn’t have.

When you scrutinize the foraging lifestyle of contemporary hunter-gatherers—people whose life-ways most closely resemble those of our ancestors—you find a lot of unpredictability.

Where is the food? When will it come? Meat is especially unpredictable. When hunters venture out to bag prey, they are usually unsuccessful. Some days, an individual hunter gets lucky and brings home the meat. But most days he comes back empty-handed.

That’s not a good thing if your kids are relying on meat as a source of protein and other nutrients crucial for brain growth, like vitamin B 12 . If your kids had to rely on your hunting success to survive, there’s a good chance they would starve. Even assuming you were the best, most skillful hunter around, injuries or illness could derail you--with devastating results.

So hunter-gatherers follow a custom that would please Karl Marx: Any man who brings meat back to the camp divides it up amongst his neighbors. The man’s kids get some meat. But so do the children of other men—men who failed to bag any prey that day.

And that’s just the beginning. When anthropologists Kim Hill and Ana Magdalena Hurtado studied a couple of South American foraging societies, they discovered that families with young children ran a chronic shortfall in food production. Not just for weeks, but for years.

It appears these working mothers and fathers couldn’t have made it on their own. How did their families survive? They were being subsidized by childless people—mostly unmarried, middle-aged men and young married couples. On average, each breeding pair (mother and father) got help from 1.27 non-reproductive adults.

Research like this lends more weight to the hypothesis that humans evolved as cooperative breeders. As Sarah Blaffer Hrdy argues, the nuclear family was never an island unto itself. Not in foraging societies with big-brained, helpless babies and fluctuating, unpredictable resources.

So perhaps we shouldn’t be surprised if contemporary families—with just one or two parents in charge of multiple kids—need help to get by. People living in modern, information-based societies may not have to worry about the sudden unavailability of wild prey. But the basic problem is still there. If you have young children, the demands of childcare slow you down. Your economic takes a hit at precisely the time when your needs increase.

And these contemporary families face a major complication. Unlike hunter-gatherers, they often lack a network of helpful neighbors and kin. Small-scale communal life isn’t an option for them. And so they rely on large-scale, state-sponsored subsidies.

Is this going to make taxpayers eager to fund programs—like public and subsidized medical care—for the children of complete strangers? That seems wildly unlikely. Does it mean that any and all child subsidies are justified? No. But it puts the lie to certain ideas about human behavior. Help for families isn’t a sign that parents have failed. It isn’t a sign of pathology or something unnatural going on.

From an anthropological standpoint, helpers and subsidies for children are business as usual. What's changed is the relationship between benefactor and recipient. And that, perhaps, is what makes state-sponsored subsidies so contentious. We're no longer connected by personal ties and mutual need.

More reading

Elsewhere I've written about our species dependence on cooperative childcare. You can read more in my posts "Mothers have always needed childcare help," and "When 'daycare' was run by kids." The latter post owes a large debt to the brilliant and fascinating work of David F. Lancy, who also blogs for Psychology Today. His book, The Anthropology of , should not be missed by anyone who thinks about or studies children.

Another essential read is Blaffer-Hrdy's Mothers and Others: The Evolutionary Origins of Mutual Understanding. And for details about hunter-gatherer subsidies and the human brain, check out:

Hill K and Hurtado AM. 2009. Cooperative breeding in South American hunter–gatherers. Proc. R. Soc. B 276 (1674): 3863-3870.

Leonard WR, Snodgrass JJ, and Robertson ML. 2007. Effects of Brain Evolution on Human and Metabolism. Annual Review of Nutrition 27: 311-327.

Text © 2012 Gwen Dewar, Ph.D., all rights reserved



Image of Neolithic woman and child © Hans Splinter / wikimedia commons

Image of orangutan rehabilitant © Frank Wouters / flickr / wikimedia commons

Image of Aché children © Shoot and Scribble / wikimedia commons