Development is a very hot topic these days, and probably has gripped our attention for a very long time as well.

The reason it’s so hot today, is that much is written to push parents to be worried that their infant and toddler is not developing well, might even be “delayed,” and should receive “services” to avoid an unfortunate future.

So in this posting, we will take a look at development, some basics on how we develop, and some guideposts that will help you know if your child has a problem, or not.

Basics of Development
All of life develops, meaning that what a life form can do at one moment in time changes, often quite dramatically, over time.  This is quite case for all people.  Everyone of us starts off as a single cell, the fertilized egg, are born rather helpless, and over many years emerge as a fully grown person, capable of a staggering range of imaginative achievements ranging from the athletic, to the intellectual, to the artistic, to the enterprising, and beyond.

For most of us, we can see the transformations we call development starting at birth.  The newborn can see and hear, smell and touch, suck and swallow, cry and look and sleep, and can learn at a dramatic pace.  But a newborn cannot walk or talk, cannot sing or write a poem, cannot grab or smile.  The emergence of all these fabulous human abilities and more is what we mean by development.

There are three key aspects to all human development:

• The timeline.  No one is born able to do all that an adult can do, the emergence of these abilities always follows a timeline.  Time is a fundamental dimension of development.
• A rather predictable progression.  Consider walking, nearly everyone goes through this sequence in developing the ability to walk: can’t walk at all, pulls to standing, walks holding on, takes a few steps, toddles in an early form of walking, develops more fluency and ease of walking, walks.  The point here is that everyone tends to follow a certain path to every commonly developed skill.
• There are highly individual patterns to development.  Despite nearly everyone learning to walk in the same sequence, the exact timing of each step, the enthusiasm or fear the progress generates, the age at which each step occurs vary wildly across a group of infants and toddlers.

A word on how misleading the average age is
Before we take a look at how to know when to worry, a word on one value can be potentially quite misleading, the average age any particular achievement in development occurs.

Consider sitting. The average age infants learn to sit is 7 months old.  The vast majority of blogs, web pages, books, and magazine articles use this item as the key guide to know if everything is OK. And that would seem to make sense, why not use the average age, after all, if your infant sits by 5 months of age, knowing the average age of attaining that skill is 7 months will prove to all your infant learned to sit in plenty of time- no problem.

The problem is that half of all humanity achieves any single developmental stage after the average age. That’s what makes it the average age.  So if you base your sense of how things are going on the average age, you quickly find about half of all humanity being told there is a problem.

A much more helpful piece of reference information is the range of ages children achieve any particular developmental step. For sitting that can be anywhere from 4 to 9 months of age.

One last point in the basics:  when your infant or child achieves a milestone tends to have no relationship on how bright they are or how well they will perform in that arena.
Say some kids walk starting at age 11 months, and others start at age 15 months. The ones who started at 15 months may turn out to be far more skillful track athletes than the ones who started at 11 months. Development is to a large extent the process of different processes in our brain coming together and activating.  When a light switch is turned on says nothing about how bright the light is.

How to Know if your Child’s Development is OK or Needs Help
Human development is described in 4 categories:  gross motor (e.g., sitting, walking, and running), fine motor (e.g., grabbing, various grasps, drawing, writing), speech and language, and social.

In each instance, we get concerned if the child’s progress establishes that they will struggle or be unable to attain a level of skill in any of these categories that would limit their ability to live their life successfully.

One approach would be to simply wait until development is completed and see what skills the child needs help improving.  The problem with this approach is that it waits a long time to help, and we do know that helping earlier leads to better results and less frustration.

Another approach is to look carefully at your infant and toddler, and at the earliest sign of a problem with development, intervene to accelerate or improve their developmental progress.  The advantage of this approach is that you can perhaps change that child’s developmental pace and outcome and prevent the impact of a limited ability in the area of concern.  There is one major disadvantage to this approach: inaccuracy.  When you try to identify whose development may be indicating trouble ahead, you cannot avoid the possible error that a child who is going to be fine is told there may be a problem.

Being Accurate
If we do accept the idea that looking carefully at our child to detect early signs of developmental concern, we must also accept the idea this sort of looking calls on us to be accurate.  By accurate we mean doing our best not to consider a child’s development of concern unless there really are indications that the development will leave the child with a truly abnormal or limiting outcome.

The chief source of inaccuracy comes from not taking into account the normal variability in development, the third of the three key properties of development noted above.

One way to think about all this could be very helpful.  For any one developmental step, say talking for example, there are three phases of variability:

• Absolute uniformity- no one at this age or prior to it can do this skill, no one.  Everyone is the same.
• Maximal variability- big differences from person to person in the ability to do this skill are seen normally.
• Near uniformity- well after the age that people tend to develop a certain skill, nearly everyone can do that skill, nearly everyone is the same.

Now let’s see how this works with talking, which starts with very early steps around 9 months of age and is well in place with most children by about 3 years of age.  So, the ages of 0-6 months are quite uniform- no young infant talks.  And also, well after 3 years of age, there is plenty of uniformity, essentially every healthy 5 year old talks, again lots of uniformity.

But look at a group of 2 year olds, there is no uniformity.  Many 2 year olds speak very well, some sound like grown-ups!  But many 2 year olds only speak in short phrases, and there are plenty of two year olds who will turn out fine who speak barely at all.

Picking out the problems
So the real challenge is picking out the child who needs help, and leaving the child who is going to turn out fine alone.

Think about our group of 2 year olds.   Say we find 20 of them who aren’t using many words yet, will all of them need help?  The answer is no.  Some of these children will turn out to have a problem, and could really use the help and benefit of good speech therapy.  Some of these children will simply be going along their developmental path in their own way and will reach the desired goal of normal speech without any help at all. Again, 50% of all people develop any skill after the average age everyone reaches it.

How to know when to act then?   We suggest some guidelines that can help you be reassured when no problem is present, and know when to act if a problem is present:

1. If the developmental step has not yet occurred, but if your child is still in the normal range of ages for gaining that skill, that is reassuring.   For example, the average age range for normal development of walking could be something like 8-18 months old.  That is, nearly all kids learn to walk by the time they are 18 months old and not many before 8 months of age.  So if your child is not walking yet, and is 14 months old, they are still at an age where normally developing children might not have learned to walk yet.   But, if your child is 26 months old and not walking, the chances of that being a sign that something is wrong is much greater.
2. Progress is reassuring.  If we think about developing the ability to walk again, consider someone who is not walking at 15 months of age.  If that child pulled herself to standing at 12 months, started walking holding on to furniture at 14 months of age, and seems tantalizingly close to letting go and taking a step now, that is more reassuring than the situation where the child can only sit at 15 months of age, cannot pull to standing.   If over several months there is no change noted towards the goal that is a sign worth being concerned about.
3. Losing a skill is always of concern.  Again, in the arena of walking, if someone was walking quite well at 13 months of age, but at 15 months of age cannot walk, that is very worrisome.  Losing a skill is very unusual and always requires evaluation.

BOTTOM LINES

1. Development are the changes that happen to all people that allow them to do certain skills that they could not possibly do earlier in life.
2. All human development follows a timeline, follows a regular pattern of change, but carries with it lots of individual variation.
3. Around the average age people gain any particular skill, there is lots of variability.   So the range of normal ages for gaining a skill says loads more than the actual average age about who to be worried about.
4. If you are in the range of normal ages for gaining a skill and making good progress, there is usually less to be worried about than if that is otherwise.
5. When a variation in development is noted, but all indications are that your child is still progressing along normally and will likely gain that skill and do well, there is less need for help.
6. When a variation in development is noted, and the indications are that progress towards the goal is not so likely, or has actually reversed, help is a very good idea.

Dr. Arthur Lavin