Is development pace in infants/toddlers really that universal?

I know there are various info sources (books, websites, magazines, etc.) that will tell you how developed a child will be at week x. However, every parent I’ve encountered has bragged about how their child was doing such-and-such weeks ahead of schedule. This makes me suspect that doctors are intentionally using a delayed (i.e. very conservative) timeline so new parents don’t freak out when their baby is a week or two behind “schedule”.

Do they actually do the contractor thing of including a bit of extra room in dates, or is this a case of cherry-picking by parents?

Parents are extremely biased. No, the literature is all correct for general guidelines, but some kids reach milestones earlier than others, and some reach milestones later than others.

Parenst aren’t going to tell you little Muffy is not meeting her speech milestones on schedule, but will happily brag about cruising and walking if it comes earlier that expected.

Really, some parents can be assholes in this regard. All kids hit milestones at different times, but there is a general guideline that parents should at least keep in mind.

If your kid isn’t walking at three years old, you should probably get that checked, etc.

I think a lot of it does come back to parent bias. It’s like the survey in which 55% of people report being smarter than average (here). In fact, even more remarkable than the 55% who think they’re smarter… only 4% admit to being less intelligent than average.

That sounds just about right for the parents that I know.

These developmental milestones all follow a typical bell curve distribution. Parents love to brag about how special their children are, though. Most parents want to believe that their children will grow up to be better, more successful, smarter, happier people than they are.

Plus, of course, most kids will, at any time, be a bit ahead of the curve on some markers, at the median on others, and a bit behind on still others. Guess which one the parents will tell everyone about?

See post 2.

I guess you were a little ahead of the curve on that one. Tell your friends.

I don’t think it’s a purposefully delayed timeline, as much as it’s a timeline where XX% (75%, 90%, etc) of kids meet the milestone. There’s a fair amount of spread in the time when kids hit each milestone. They want to capture most kids within the timeline, so a lot of kids will hit the milestone early.

The ‘universal’ development patters continue till adulthood. It does get more spread out as the children get older, but the pattern of physical, affective (emotional/social), and cognitive development are age classified and a fair gauge realizing that there will be some variation. With experience, looking and interacting with the child one can easily classify them where they are, at which time you don’t really use age as a gauge anymore.
Yes parents will often tell you that their child is ahead of the curve, usually, I have found this is not the case the parents are just seeing what they would like to see.

Occasionally I will get one that is ahead by quite a bit, that is a lot of fun not only because the child can do more, but it is a refreshing change of the usual pattern of children as just because they are ahead in one aspect (such as physical), does not that they are also ahead in the others (affective, cognitive). So it may be like getting a child that is 7 in one regard and 4 & 4 in the other 2, normally children are more balanced with perhaps one trait slightly leading the others


As a tool to look for problems, the average milestone is useful. As said above, if the child is three years old and is not talking and walking, there’s a problem to be addressed. But whether the baby walks at 10, 12, or 14 months is probably irrelevant.

For example, my parents said that I walked at 9 months of age. That was probably the last time I was ahead of the curve on athleticism or balance. I was always the last one chosen for sports teams in school, and today I would be voted most likely to fall down.

I was going to question the premise.

I’m a parent of two boys, and all the baby milestone books I read are always couched in “By X months, your baby, will probably be able to do A, may possibly be able to do B, and might be starting on C”, and almost never as “By X months, your baby can do A”. Our pediatrician is forever telling us "yea, kids are all over the place on that milestone, I wouldn’t worry about it unless they still can’t <whatever> after the next couple of checkups.

It doesn’t help that plenty of babies skip milestones - for example, my eldest went straight from rolling to walking with very little crawling in between.

Also, there’s a variety of exercises they use when testing. So a test may include stacking three blocks and locating a ball under a bucket. One child may do one, the other child do the other and both “pass” the test as age appropriate development even if they failed to do the other (really, it’s like twenty different tests and they’re expected to perform a set number for their age).

When our kids were young, every time we saw a doctor, they were always careful to point out that these are just guidelines, and there’s a HUGE range of “normal”, because kids develop differently. I’m sure some doctors aren’t as careful to get that across, and some parents don’t take those caveats on board for whatever reason.

Yeah, and while there are teh “At 10 months, some babies can do X, some can do Y and some can do Z”, there’s also the section that says “If your child is not doing W by 10 months, see your pediatrician”, and W is usually some behavior or something that was on the 6 month list for “Some can do W”.

Examples: Babbling is on the 4 month CDC guidelines of what they might be doing, but it’s on the 9 month “Act early by talking to your child’s doctor if your child doesn’t” list of behaviors.

So just because a kid isn’t babbling at 4 months, or because some other kid was babbling at 3 months, it doesn’t mean something may be wrong. If you get to 9 though, it’s worth looking into in detail.