How Baby Slings Shaped Humanity


Baby wearing around the world

Have you ever noticed how calves, horses, and dogs – to name a few – can stand up almost immediately after being born? Isn’t it interesting that these animals who are significantly less intelligent than we are have such superior coordination at birth? The answer to this seeming mystery lies in the fact that, ultimately, human brains have a much longer path to maturity.

The Task of Building a Large Brain Retards Physical Growth

The progress of a developing animal body is proportional to the development of the animal’s brain. So the brains of calves who hop right up when they’re born are at further point in development than the brains of humans when we are born, laying helplessly in our mother’s arms. The reason these animals are more developed than humans are at birth is because they will experience less brain development overall than we will, and so they complete their full brain development faster than we do. This translates to mastering physical milestones faster.

All animals, regardless of their ultimate brain size potential, take their first steps at basically the same point in brain development. This means that the brain development of a newborn calf is about as far along as that of a one year old human’s brain at birth. This doesn’t mean, however, that cows are smarter than people. Cows just won’t have nearly as much brain to develop in the end so the process is quite a bit quicker. Human babies will develop larger brains than four legged animals, and with that comes more skills to master, such as language and hand-eye coordination. This takes a long time, comparatively.

For example, it takes a whole year for human babies to catch up and take their first steps; it takes 5 months for chimpanzees, and 1 or 2 months for vervet monkeys. But this is only because a human brain is simultaneously developing in areas that vervet monkeys as not.

Why Humans Start Out So Underdeveloped

According to Archaeologist Timothy Taylor, larger brained, somewhat upright animals, like primates, had to overcome the problem of birthing large heads from relatively small pelvises. The problem is even more pronounced in humans whose pelvises are dramatically narrowed due to their fully upright stance. Consequently, humans evolved to give birth while the baby’s head is still small and the brain underdeveloped. This allows for the brain and head to continue growing outside of the womb.

For some perspective, the weight of a non-human primate newborn brain is around 42 percent of its adult weight (i.e. it doesn’t have far to go before it reaches full development), while a human baby’s is a measly 29 percent (i.e. it has a long way to go before it is fully developed).

Babies are born with stunted brain development overall because there is more brain that needs to be built in the end. Each developing region of a non-human brain is not so complex as ours and so does not take as long to fully develop. In humans, since the brain is not well developed at birth, the body is not well controlled by the brain. Consequently, the body waits for the brain to catch up.

But how is it that humans have been able to get away with birthing such high maintenance babies? Humans have to travel, hunt, gather, take care of their homes, and sometimes quickly flee. How could they manage all of these demanding tasks with a delicate, helpless creature to take care of? The answer lies in the baby sling.

Baby Wearing Was Requisite for Child Care

Due to the fact that humans are born helpless, they require a period of intensive neonatal care unlike any other animal on earth. They must be constantly supervised as they cannot yet follow or imitate their mothers. Human mothering is not a passive affair as it is in some species since human babies are entirely dependent upon their mothers. As the human brain was evolving to be larger and smarter, and babies more helpless, Paleolithic females came up with a solution to this nearly debilitating predicament. They created the baby sling.

When our early ancestors came down from the trees and started eating, preparing, and hunting meat, the human brain started to grow. As the brain became larger and we started standing upright it became more difficult for our babies to fit through the birth canal. Humans, already adept at using tools, rose to the challenge of infant helplessness and created the baby sling. It was this invention, claims Timothy Taylor, which facilitated the continued evolution of large brained hominids, ultimately culminating in the emergence of language.

About 2.2 million years ago (Timothy Taylor has analytically dated this back 2.2 million years. There are no relics of cloth from that long ago) the development of the human species was ready to explode. Here’s why: The baby sling allowed for a longer period of helplessness. It gave the developing baby the chance to take in information about the world from a calm, safe, and organized perspective. The rhythm of walking and heartbeat that a baby feels while in a sling bears some resemblance to gestation. In a sling, a baby’s energy can be channeled into physical and behavioral development. While a baby is in the sling it can observe the world around it and learn a great deal.

As Dr. William Sears has himself said, carrying humanizes a baby.”

What Happened to Baby Wearing?

Traditional cultures around the world continued to carry their babies for 2.2 million years, even after they designed beds and rockers. But in Western culture the tradition passed in all but the poorest households. In Europe, the poor continued to carry their babies while the rich placed their babies in carriages.

A stigma grew around the ability to leave ones baby alone versus the need to carry it around. Poor, working mothers had to carry their babies while they cooked and cleaned. Rich mothers could leave their babies virtually unattended in a crib while socializing or doing other activities that the poor could not afford to do, in rooms that the poor could not afford to have.

Even today, all around the world, carrying a baby is often still associated with low social and economic status. Baby slings were replaced by strollers, baby swings, bouncers, and walkers. This trend is worldwide as countries become more Westernized. However, with the resurgence of interest in the ancient practice of baby carrying, mothers of all classes are again beginning to nurture their babies with this ancient human practice.

Baby Wearing Finds Its Way Back Into Modern Culture

Westerners learn to use a baby sling

Carrying a baby in a sling was popularized in the United States by Dr. William and Martha Sears in 1985. The Sears’ noticed how cultures around the world regularly carried their babies and that their babies seemed more content.

As a result, the Sears family tried it out on their own kids and it worked miraculously. They reported that the more they used the baby slings, the less their babies cried. The husband and wife duo created a baby sling for sale and coined the (now trademarked) term “babywearing”.

Benefits of Baby Wearing

  • The rhythmic up and down movement of walking is akin to being in the womb, which was a safe, warm, ideal place to grow. The movement also helps to develop a baby’s inner ear.
  • Wearing a baby calms a baby. Calm babies do not cry and fuss as much.
  • Infant brains are more organized due to the rhythms of heartbeat and walking.
  • Babies are an active member of everyday duties and conversations. They are able to pick up more about the world while being immersed in it. While calmly sitting in a sling, they can watch facial expressions, learn language faster, and become familiar with body language.
  • Because babies are learning more about the world they live in, independence is established earlier.
  • A mother’s sensitivity to its baby’s needs is heightened with the baby so close by.
  • Breastfeeding is convenient and discreet.
  • Physical contact with a baby increases a mother’s oxytocin. Oxytocin facilitates breastfeeding and deepens the bond between a mother and child.
  • Wearing a baby is good exercise!
  • A sling makes it easy to take a baby out in crowds to places where it may be difficult to push a stroller.
  • With the use of a sling a dad can share childcare and develop an early bond with his child.
  • The sling makes it possible for a mother to care for other children without neglecting the new baby.
  • Wearing baby decreases the risk of developing positional plagiocephaly (“flat head syndrome”) which is caused by extended time sitting in car seats or laying on the back.

Consequences of Abandoning this Behavior

I think it is obvious from the list of benefits of babywearing that there may be some consequences of abandoning the sling in favor of a carriage and a crib. It may even be that many of the behavioral and emotional problems, the attention deficit, and lowered intelligence which many thousands of children experience these days are a direct result of having less physical contact with their parents in the first two years and a lack of the safety and rhythmic movements felt while being left to lie alone. If carrying a baby helps to build independence, intelligence, and calm, then what might happen to a baby and the baby’s brain development when this tradition is removed?

Which Style to Choose

There are so many styles of baby slings, backpacks, and carriers to choose from these days. I used many of them when my daughter was growing up but my favorite was the Ergo. This backpack will carry a baby from birth through 3 or 4 years old. Yes, really 4 years old! It’s not as difficult as it may seem to carry a kid that age because you build the muscle as they grow.

Below are a couple of pictures of me carrying my daughter when she was 2 and when she was 3.

A long day hike through the redwoods

Thanks to the Ergo, I took her everywhere

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  1. I think it is so cute when I see dads carrying a baby in one of those Baby Bjorn carriers. I am definitely getting one if I get pregnant.

  2. I agree. It’s a good sight to see couples helping each other out.

    I read some research recently about regarding bjorns and others like them. Some say that carriers which hold up babies by the groin area might stunt spinal development. There hasn’t been enough research on it to say for sure so don’t take it as truth but I thought I’d throw that out there anyway.

  3. Fascinating possibility. The first time I was exposed to the idea that we actively shaped our evolution last year when I read that we’ve been cooking for a couple million years. Now this! I wonder what next?

  4. The theory was absolutely stunning to me when I read about it in a book. I felt I just had to make it more accessible as an article. It’s an example of the profound consequence of coincidence. We absolutely have shaped our evolution! I think that’s beautiful.

  5. Last year, my wife, 6 month old son and I all went down and spent three weeks traveling in Peru. It was fascinating to see that in many of the towns outside of the big cities still used the traditional blankets not just to carry children, but to also carry other things (one woman carried food for her animal around, for example). Additionally, one of the local women there insisted on carrying our son around in one.

    Another local woman, in one of the larger cities was carrying around her infant around in one while she was trying to sell us some pottery. As we were negotiating a price (the most popular way to pass time in Peru was as near as I could tell bartering), the baby started to fuss. Without missing a beat, she managed to slide the bundle around and start feeding her (I’ll assume it was a baby girl, as I don’t think I ever saw her) without missing a beat. There was no awkward (step 1: remove baby from harness, step 2: find a place to sit down so you can nurse the child, step 3: cover up because you’re in a public place and are self conscious) series of steps that she had to go to in order to care for her child. It was smooth, compacted, and efficient. Pretty cool stuff, for sure.

  6. You went to Peru with your six month old? You guys rock!

    In the picture above I really like how the lady is carrying not only her baby, but some straw. I so admire the efficiency of traditional cultures.

    • You know, the trip went great. Traveling before he could really get around was a great idea. What’s more, we got special treatment because we had a little baby with blue eyes – so that was fun, too.

      The most efficient part of the whole setup is that it’s nothing more than a special way of folding a blanket. No straps, buckles, zippers, or any of that noise. Just simple and effective.

      • Haha! I know what you mean. My daughter is bleach blonde with blue eyes. I took her traveling through Colombia last year and she was definitely the center of attention everywhere we went.

        I agree with you about the carriers. They can be so hard to use! I tried a few of them myself couldn’t figure them out. While a blanket is awesome, I have a soft spot for the Ergo. It is so comfortable, has pockets, and looks a little more modern. ;)

  7. I am so excited to see you post this!!! Babywearing is such a natural extension to leading nutritionally healthy lives. Why not nurture our children in the healthiest way possible. It encourages breastfeeding on demand and keeps baby content. Babywearing was the best way to go places or get things done with my babies/toddlers. They were worn in slings until about 3-4 years old. They both have fond memories of being carried in their slings.

  8. Great post. When my youngest was a baby I used 2.5 yards of fabric. Bending over, with him on my back, I put the center of the fabric over the baby, wrapped both ends around myself and tied in a knot under his but. Very secure and comfortable. It was inexpensive and he loved it.

  9. Normally “butt” (probably short for “buttocks”.

    ” tied in a knot under his but”

  10. It’s funny that the Searses popularized babywearing in 1985. My stepmom was wearing my baby brother around several years before that. We lived in the Philippines from 1978 to 1981 and he was born there in 1978. When he got too big for the slings she put them up in storage and I never thought about them again til it started really getting faddy about six or seven years ago.

  11. Peggy, what do you suppose they do, or what would you do, in the event of twins?

    I ask because I myself am one, and the rate of twin births in my family is high. Apparently the more you have, coupled with other factors, such as age, and genes, the more likely you are to have twins. I have two single births already, so……. it’s a source of interst for me. :)

  12. Now that businesses are adapting to help new moms, I wonder whether many people see these in the workplace?

    • Good question! Parents at home can actually get a lot of work done while holding their sleeping baby at the computer while they work. If a mom nursed, ate healthy, and carried her baby, the baby might be calm and quiet enough to join her at work. Maybe for half days or something.

  13. I wore two of my children in baby sling created by the Sears family. My youngest was a definite requirement as he came so soon after the second child who was a major handful and still is even as a teenager. Being short and my babies were so large carrying a baby carriers /car seat was crazy much less attach to the grocery cart and see around it. And when your kids start at 9pounds and 22 inches and more well lets just say I didn’t need a weight lifting program for a while. It was some of the greatest moments to go to movies, shopping, festivals etc wearing the baby and not having to fit a stroller through crowded spaces, or carry heavy car seats, and yet hold baby while I could use both hands to cook clean, play with the older children. I began teaching other moms how to wear their baby even gone as far as taking certain shawls or blankets to wear babies still when babysitting grandbabies or friends kids. New moms get watchfull as I carry their kids like that, but once they see baby sleeping and happy they relax and beg to learn.

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