We listen to a lot of white noise these days. Not long after the girls came home from the hospital, we got a machine for the nursery (plus another kind for downstairs), so we’ve heard a lot of wind, rain, ocean, and sundry other things that hiss, whoosh, and swoosh. The nursery machine has a setting where you can combine sounds, so I like to keep the babies on their toes by combinations like heartbeat + seagulls, or rain + buoy. I hear the vacuum is also a very effective source of white noise, but I hate to waste the electricity, and I don’t know how to turn it on anyway. In the car, we usually find some static between stations to crank up for the girls until they fall asleep. I sometimes listen to white noise (rain or waterfall, usually) when I write, because it’s effective at blocking out distracting sounds without being distracting itself. So, I’m not new to white noise, but until recently, I never gave much thought to why it works.
Kate recently ordered a DVD by some guy named Dr. Karp called The Happiest Baby on the Block. There’s a companion book (which we don’t have) but the DVD has Dr. Karp explaining and demonstrating techniques to trigger the “calming reflex” in babies. There’s nothing revolutionary about the stuff he demonstrates, but it’s full of the kind of wisdom that if you’re not lucky enough to have a wise grandmother or experienced baby person to hand down to you, you don’t necessarily figure out on your own. It’s stuff like how to swaddle them, what kind of rocking works best, positions most babies like to be held in, and so on. One of the techniques he covers is how to give an effective “shhh”.
The “shhh” sound is certainly very familiar to me as a sound meaning “be quiet”, but I never really thought about why it means that, or why it works on a baby. I can’t think of a way to prove it, but the theory that sounds reasonable to me is that the “shhh” - or any white noise, really - simulates what a newborn was used to hearing in the womb. I know from listening to and recording the twins’ heartbeats in the womb that it is not a silent environment in there. Besides the heartbeats of their mommy and themselves, there’s lots of whooshing going on from amniotic fluid and blood flowing around. Just as it makes sense that swaddling is comforting by creating a tight womb-like embrace around the baby, it makes sense that “shhh” or other white noise comforts by being one of the few sensory stimuli that is familiar to them.
One of Dr. Karp’s tips that made sense when I thought about it but hadn’t really occurred to me is that for maximum effect, the “shhh” has to be loud. He demonstrated by getting right next to (but not aimed into) a crying baby’s ear, and shh-ing very loudly. I’d shh-ed my girls plenty of times before watching the DVD, but like many people, I was deliberately “gentle” about it, thinking a loud hiss would be unpleasant to them. In fact, if you consider that womb environment, they’re basically underwater, and if you consider what sounds are like underwater, it’s pretty loud. Keeping up a loud “shhh” for more than a minute or so — even with plenty of breaths — is challenging to do without getting lightheaded, but I’ll be darned if it doesn’t work like a charm. It doesn’t work every time, but in combination with other techniques, and when the timing is right and the stars are aligned, it has a lot more effect than the quiet, distant shhh ever did.
I wouldn’t recommend going up to a stranger (or any non-infant, really) and loudly shooshing them in their ear to shut them up, but the next time you say “shh” to someone and they get quiet, consider that the reason it worked might be that you just gave them a flashback to the womb.
