Ben Wiseman

Everyone knows what a hassle new parents are on Facebook, right? They overshare. They post endless pictures of their new bundle of joy, flooding your feed with drooling infants. Last summer saw the creation of a browser extension—UnBaby.Me, since renamed Rather—that fought back against the tide, auto-detecting baby images and replacing them with less-annoying material, like cats or bacon. "A brilliant and sanity-preserving idea," a Forbes writer gushed. Except for one thing: The entire premise is wrong.

Recently, Meredith Ringel Morris—a computer scientist at Microsoft Research—gathered data on what new moms actually do online. She persuaded more than 200 of them to let her scrape their Facebook accounts and found the precise opposite of the UnBaby.Me libel. After a child is born, Morris discovered, new mothers post less than half as often. When they do post, fewer than 30 percent of the updates mention the baby by name early on, plummeting to not quite 10 percent by the end of the first year. Photos grow as a chunk of all postings, sure—but since new moms are so much less active on Facebook, it hardly matters. New moms aren't oversharers. Indeed, they're probably undersharers. "The total quantity of Facebook posting is lower," Morris says.

And therein lies an interesting lesson about our supposed age of oversharing. If new moms don't actually deluge the Internet with baby talk, why does it seem to so many of us that they do? Morris thinks algorithms explain some of it. Her research also found that viewers disproportionately "like" postings that mention new babies. This, she says, could result in Facebook ranking those postings more prominently in the News Feed, making mothers look more baby-obsessed.

I have another theory: It's a perceptual quirk called a frequency illusion. Once we notice something that annoys or surprises or pleases us—or something that's just novel—we tend to suddenly notice it more. We overweight its frequency in everyday life. For instance, if you've decided that fedoras are a ridiculous hipster fashion choice, even if they're comparatively rare in everyday life, you're more likely to notice them. And pretty soon you're wondering, why is everyone wearing fedoras now? Curse you, hipsters!

Frequency illusions are self-perpetuating cycles enhanced by lazy journalism and punditry. One reason people think new mothers post a lot of baby pictures is that trend pieces and op-eds claim they do. (Indeed, trend journalism is essentially a form of intellectual trolling designed to create frequency illusions. "Why is everyone suddenly listening to Wilco again?") Yes, some moms post about their kids every 10 minutes. You may have one in your feed right now. But the behavior is not widespread or incessant.

The way we observe the world is deeply unstatistical, which is why Morris' work is so useful. It reminds us of the value of observing the world around us like a scientist—to see what's actually going on instead of what just happens to gall (or please) us. I'd hazard that perceptual illusions lead us to overamplify the incidence of all sorts of ostensibly annoying behavior: selfies on Instagram, people ignoring one another in favor of their phones, Google Glass. We don't have a plague of oversharing. We have a plague of over-noticing. It's time to reboot our eyes.