At some point in the past four months of having an infant, I took note of my preference for picking him up with his head on the left side of my body, but didn’t think too much of it. I figured the preference was just one of those left-hand-bias oddities in my life, despite being right-handed, just like how I instinctively hold a hockey stick left-handed.
However, it turns out that “left-handed cradling bias” is a real thing that scientists have confirmed in a study. My wife passed along this fascinating nugget to me, having encountered it in a newsletter interview with Abigail Tucker, author of Mom Genes by the fantastic Emily Oster (whose data-driven parenting books every expecting parent should check out). The relevant portion of the interview with Tucker is quoted below:
The closest thing that women have to an automatic mothering behavior is something I’d never even heard of after having multiple kids. It’s called left-handed cradling bias. Humans and other mammalian mothers, from flying foxes to walruses, are prone to carry or keep babies on their left. This apparently helps transfer the maximum amount of information about our babies’ state to the right hemisphere of moms’ brains, where our emotions are processed. It also allows infants to view the more expressive side of our own faces. Some scientists even suspect that women who buck the trend and hold babies on the right are more likely to be depressed. (Researchers have used family photo albums to probe this last idea, which is just a theory for now.)
I am a resolute left-holder—I find it weird to even change a diaper if the kid’s head is on my right – but that only gets you so far in twenty-first century America, you know?
Like Tucker, I am a “resolute left-holder” and also find it weird to change my baby’s diaper with his head anywhere but to my left. In fact, the most stressful moment of my day is often when I am tasked with putting him down to sleep when his head is on my right side. It just doesn’t feel right! I’m happy to have science back up what I’d discarded as a random preference.
Taylor Coe 