Understanding Newborn Behaviour

By Sarah Pugh

It's unfortunate they don't come with manuals. But with a bit of understanding of babies' needs and underlying wiring, you can often make some good guesses about how to keep them happy, and you sane.

The key to understanding human babies is knowing they are essentially immature primate young. Yes, they're monkey babies, born too early. They have to be born earlier in their development than other primates because their heads are too big.  That's what scientists call an "evolutionary trade-off."

How does knowing that help? Like all primate young, human babies have instinctive needs for closeness to a parent, physical comfort, and frequent food. That constitutes the entire set of needs. But because human babies are biologically premature even at full gestation, they aren't able to fulfill many of those needs themselves, as other primate babies do. They can't cling to a parent, or move much. They can't even access food at will; they rely on the parent to offer it. So if they can't do something, they need a way to prompt a parent to do it for them. The only means they have at first is, of course, crying.

Human parents, therefore, have to use those massive craniums to figure out a way to keep the baby relatively happy until she can meet her needs herself.

As far as feeding goes, we need to look at what's biologically normal. Animals that have litters they leave for hours tend to have babies that nurse quickly, get a lot in one go, and sleep for the rest of the time. Herd animals expect their babies to be up and walking with the grownups instantly. They feed when they stop, they drink a lot at each time, and the milk composition is geared for incredibly fast growth. Other animals, including all primates and marsupials, have young that cling or are carried, and grow relatively slowly. These animals' offspring are all snackers. They eat little, but they eat very frequently, at least at first.

Humans are biologically among the snackers, at least at first. In some cultures, this is acknowledged. Anthropologists have recorded average nursing behaviour among some tropical hunter-gatherer groups as babies feeding for two minutes, every 13 to 20 minutes. But here in North America, it's more common to hear that your baby needs to feed every three hours and take four to six ounces.  Fortunately, babies are pretty adaptable-humans have spread out to occupy many environments, and it's not practical in many of them to nurse constantly. Nevertheless, if you have a newborn who seems hungry all the time, but will never nurse for more than a few minutes before losing interest or falling asleep-well, there's nothing necessarily wrong there.

Westerners also tend to overlook the instinctive need to be held, and view it as an inconvenience and not a real need. It is most definitely a physiological need-but yes, it's also an inconvenience. We're the only animal with such dependent young to not have a convenient pouch in which to put them.  Again, this is where our craniums come in, and other clever humans have invented a plethora of baby-carrying devices.

All primate young show immediate stress responses if they're not within arm's reach of a parent or other adult, and human babies are no different. The fact that they're not in any actual physical danger is irrelevant, and many if not most babies will cry within minutes of being put down and left alone. (Evolution weeded out the ones who quietly cooed at the hyenas.)  

Many parents ask if it does any harm to let a baby cry, if he is fed, dry and warm. There is controversy about this, but studies have shown that sustained crying, particularly with parental separation, raises babies' cortisol levels. Chronically high cortisol levels in adults are associated with health problems, usually of the cardiac and digestive inflammatory variety, and while we don't know definitively if cortisol is associated with similar problems in babies, it's probably better to avoid sustained solitary crying if possible.

The other reason for holding, beyond meeting an instinctive psychological need, is for babies' internal comfort. Because they are born as prematurely as possible, human babies can have underdeveloped digestive systems (even full-term). That's why they need help burping-but more than that, they can have difficulty moving food efficiently, and reflux is quite common. These problems can be exacerbated by feeding practices, and then compounded by trying to lay the baby down on its back. Carrying a baby ensures that it's almost constantly in motion.  This helps its little insides work better, and helps the baby stay more comfortable. Every baby will have her own favourite way of being carried, and savvy parents use a carrier that's comfortable both in and out of the house. (Wrap-style carriers tend to work best once you get them figured out.) If you suspect your baby has a touch of reflux, feeding little and frequently, and carrying him upright, are almost always your best bets. (For severe reflux, talk to your doctor.)

And no, you can't spoil a newborn by carrying him all the time, or by nursing every time he squawks. These things resolve naturally over time. The baby you couldn't detach becomes the toddler for whom you need a leash, and the newborn who nursed constantly becomes the child who won't even eat ice cream if there's a new and fascinating kind of bug in the back yard.  Parenting a newborn is hard work, but it doesn't last, and a time may come when you miss the complete and constant dependency.

Sarah Pugh is a post-partum doula, writer, and mom.