It’s spring of 2016, my husband and I are expecting a baby, and I am being particular about only one thing: the stroller. “I don’t care if it’s a boy or a girl, I don’t care how we name it, all I care about is that we get the Stokke stroller.” Why the fixation? It is the only stroller that holds the child practically in your face, strongly suggesting that you talk to the baby all the time while walking outside. Why is that so important? Because it is one of the most significant things one can do for early brain development. Based on the literature - and contrary to popular belief - it may very well be that having a face-to-face stroller is even more important than reading books to children up to age two. Here’s why.
Is it because babies need to hear as many words as possible?
Well, not quite, but let’s start there anyway. We know that talking to little ones is essential for babies to learn to speak. Throughout history people have run experiments in child deprivation, raising children without words to see what ‘natural language’ would emerge. None did. Twenty five years ago, the now famous “Early Catastrophe: The 30 million word gap by age 3” study by Hart and Risley estimated that the difference in how many words were addressed to children before age three between the highest and lowest socio-economic categories was a staggering 30 million. This had two consequences for the children who were least spoken to: not only a poorer vocabulary, but also a weaker ability to add new words. These children added fewer words to their vocabulary than their peers from then onwards. Their vocabulary gap widened through the school years.
Building on those findings pediatricians encouraged parents and nannies to read to children. The idea was that the vocabulary used in stories is more varied than what is encountered in everyday life. However, the quantity of different words is the least important aspect of parent-child interactions.
Does what we say also matter to how much babies learn?
Yes, indirectly, it does. The 30 million word gap study had another finding. What varied between families was not just the quantity of different words, it was also what kinds of things were said. The more fortunate children - those who also got spoken to the most - heard about six encouraging sentences (“good job”) for every discouraging one (“stop that!”) Those that were spoken to the least were also discouraged twice as often as they were encouraged. The authors concluded that what families convey is not just vocabulary, but “an entire general approach to experience.” Some kids learned implicitly that while interacting with their parents they would almost always hear something pleasant, while the least fortunate ones learned that words were far more frequently unpleasant.
Should we talk to babies, or speak with them?
This is where things become really interesting. It turns out that the most important aspect of parent-child communication is interactivity. Ten years ago, a study by Zimmerman showed that two-sided communications with babies were six times more effective in language acquisition than simple exposure to adult language. He urged pediatricians to encourage caregivers “not merely to provide language input to their children through reading or storytelling, but also to engage their children in two-sided conversations.” I suspect that this is why there is an emphasis on sharing mealtimes in groups around a table. Taking turns talking, asking questions and answering gives babies a voice, which is significant. Still, that setting doesn’t usually let them guide the parent in conversation.
How about letting the child direct the interaction?
What makes strolls outside so important is that they encourage the most valuable kind of parent-child interaction. Strolls are unique opportunities for joint attention dedicated to discovery, and much of discovery is child led. When kids are outside (or in supermarket shopping carts) parents are inclined to be responsive to whatever catches the kids’ attention. These interactions are tilted towards the kids, and thus establish the most fundamental element of interactivity, which is the fluency and connectedness of communication (turn-taking relationship, as explained in Hirsch’s 2015 study) Since babies utterly depend on parents for everything they do, to have the opportunity to lead interactions - with their looks, their vocalizations, their reaching hands - is precious.
Connectedness wires the brain!
Since 2018, several studies have demonstrated how this interactivity (ie conversational turns, not just exposure to words) affects brain development:
They activate the language center (Gabrieli study)
They generate more white matter connectivity of the dorsal language tracts (Romeo study)
They show significant benefits in IQ, verbal comprehension and expression ten years later (Gilkerson study.)
Why don’t stroller manufacturers act on this information?
A New Zealand study from 2013 summarized the very few studies done to date comparing babies' experience in face-to-face versus away-facing strollers. The UK’s Suzanne Zeedyk in 2008 observed that parents in face-to-face strollers where more than twice as likely to be talking with their child - yet over 85% of toddlers were in away-facing strollers. Her findings led UK stroller manufacturers to promote the value of face-to-face strollers. That is not yet the case in the US. For example, The New York Time’s much consulted “Wirecutter” recommendations platform makes no mention of kids’ orientation and its benefits.
Until what age should a child be in a face-to-face stroller?
The Gilkerson study (linked above) points to conversational participation as particularly important 18-24 months. So hold on to that stroller until the kid is at least two.
We and our baby's nanny talked with our son constantly while spending the days outside with him on the stroller. We fully credit the stroller for his verbal ability and sociability!