Pram Good, Stroller Bad…What? No wonder this is a "report".

A recent post up at the Frontal Cortex points approvingly to a study of strollers, prams, toddlers and parental conversation. Jonah Lehrer concludes:

It would be nice to see this research filter down to stroller manufacturers, so that even cheap plastic strollers allow the infant to interact with the parent.

Very interesting. Must be strong evidence, no? And after all, we all want our little wackaballoons to be as smart and advanced as possible, do we not?

GoodThe take home message of the UK National Literacy Trust press release is:

The most popular style of baby buggies – those that face away from the pusher – may be undermining children’s development. Children in such buggies are significantly less likely to talk, laugh, and interact with their parents, than are those in buggies that face the pusher, according to the first ever research study on the psychological effects of buggies on babies. It is published today by Talk To Your Baby, the early language campaign of the National Literacy Trust, an independent charity that aims to change lives through literacy. It was funded by the Sutton Trust.

Okay, first bad sign is the lack of a citation to a peer reviewed journal article. Hmm. Moving along, there’s a link to another page with an even more aggressive summary:

The report concludes that life is emotionally impoverished for too many babies in buggies facing away from their pusher. Therefore, TTYB calls on manufacturers and retailers to create more affordable two-way facing buggies. Parents with such models should utilise the face-to-face option as standard, so that young children and their carers can talk and listen to each other as they are out and about.

and finally the actual report in pdf form. More evidence of a lack of formal peer review. Calling the blogosphere and OpenScience fans I suppose. Lehrer’s post was a bit on the credulous side I fear, so let’s get to it.
The biggest part of the report is from a field observational study:

The final sample comprised data on 2722 parent-infant pairs. This derives from a total of 39 hours of observations carried out by the 57 volunteers, conducted over two months during the summer and autumn of 2008 (August and October). Observations were collected in 54 cities and towns throughout the UK, located in 22 regions.

BadIt’s a covert observational study so some things such as child age were estimated. The first obvious issue I thought of on reading the Frontal Cortex brief is covered in the first “research question” table on page 7. For the under 1 yr old babies 60% were in strollers and 34% were in prams (6% carried, none walking). For 1-2 year olds 86% in strollers and 4% in prams (3% carried, 7% walking). For the 2+ year old demographic, 37% in strollers, 2% in prams, 3% carried and 58% walking. Hmm. This would seem to me to be a major confound unless we know something about the major dependent variable (time parents are talking to kid) across the age ranges in most settings.
Then we come to the second data table on page 8 in which we learn that the under 1 yo babies were vocalizing only 5% of the time and sleeping 35% of the time whereas for the 2+ yo kids they were vocalizing 38% of the time and sleeping only 2% of the time! Crying was the same at 2% across age groups.
Okay, now down on page 9 of the report we come to the percent of parents that were talking to their kids. Rates were pretty low wiht 13% talking to under 1 yo babies, 17% to the 1-2yo and 35% talking to 2+ yo kids. Eleven percent of parents were talking when using a stroller and 25% with a buggy however carryied (46%) or walking (47%) children received much more parental conversation. (And here I’m trying VERY hard not to speculate that most of the conversation for new walkers revolved around “Get away from the kerb”, “stay out of Missus McGillicudy’s flowers, “c’mon keep walking luv'” and the like.) So we’re not getting very convincingly away from the idea that the amount of parental vocal attention correlates best with age of the child.
Back up to the end of page 8 the table reports that of awake babies, 12% in strollers were vocalizing versus 17% of pram babies…AHA! except oops, 6% of stroller babies were twisting around trying to get their parent’s attention (versus 1% of pram babies). So basically the same number are engaging in interaction with the parent and frustratingly the data do not get at the key issue. Namely, are parents ignoring their vocalizing or attention-attracting stroller babies relative to pram babies? The analysis doesn’t tell us. Oh wait, here we go. Down on page 10-11 we discover that attempts to get the parent’s attention via crying or turning around were unsuccessful in the 8% that tried it.
Really? Crying babies were being ignored by the parent? This suggests we have more factors to look into having to do with parental proclivity to respond to baby’s every exhibited need or to let them cry it out. Temporary frustration measures caught in the brief-sampling study versus sustained parental traits. Which reminds us to ask if those parents who use prams are a very different type of parent from those who use strollers, in which case mandating a pram style would not necessarily increase parental interaction with baby.
So part two of the study was an experimental manipulation in which 20 mother-infant pairs participated in a walk in which stroller / pram configuration was evaluated in each pair over half the distance. Mothers talked more when the baby was facing them. It’s a nice first try but under the circumstances highly unsatisfying. The mothers were not blinded to the study manipulations from what I can tell, probably couldn’t be given that it was repeated measures. I mean gee, how obvious would it be? It was a one-time deal so the novelty for mothers who were unused to a given configuration would be high. Who knows if behavior would be sustained under real world conditions. The aforementioned issues having to do with innate parenting traits are important given the relatively small sample size, no doubt influenced by who was available to participate in a study.
And finally the study seemed to focus only on the in motion phase of a trip in a stroller/pram. From personal experience there is a great deal of variation in what a parent does with a child when out and about with the stroller. Some will essentially get the kid out and carry it at the slightest stop for shopping, coffee, whathaveyou. Others will leave the kid in the stroller or pram no matter what. So the percentage of the overall time in the day the kid is in the stroller / pram versus being held/carried is also important.
There are a lot of fairly obvious questions to ask. Questions that in many cases I bet would pose substantial problems should this thing be submitted to peer review for publication. Not that there is anything wrong with the studies conducted, they are just preliminary or incomplete. It appears to me to be far to early to use these data as good evidence that stroller manufacturers should be somehow called upon or tut-tutted to make rear-facing carriers.