- [Instructor] I want to talk about motor development
as it relates to the nature-nurture debate.
And the nature part of this debate
is spoken about in terms of maturation.
Which refers to genetic factors as well as anatomical
and neurophysiological traits that drive motor development.
And we know that motor skills are driven
by internal biological factors for a number of reasons.
For example, we know that identical twins
typically begin to walk on the same day.
Much closer than non-related infants of the same age.
Other evidence for this is the fact that children
all over the world tend to develop skills
at the same time and in the same order.
We also know that blind children tend to show
the same timing and progression,
and they obviously could not have learned this
through observation and imitation of those around them.
And this actually makes a lot of sense
when you think about it.
As children grow, their brains and their muscles
grow as well.
And before areas of the brain like the cerebellum develop
and before the muscles are strong enough,
infants simply aren't developed enough
to allow for things like crawling or walking.
They can't sit up or crawl or walk
without that biological support.
No matter how much practice or experience
a parent tries to give.
And I want to point out that the same is true
for the muscles involved in bladder control
and bowel control.
Toilet training simply can't happen
before those muscles are developed.
It doesn't matter what rewards or punishments
parents try to give.
But the environment can still play an important role
in the development and motor skills.
How much space and time a child has to practice these skills
can have an affect on development.
Culture can also have an influence on development.
For example, these days doctors typically recommend
that infants sleep on their backs
instead of on their stomachs.
And this is great advice.
That small change in how children sleep
significantly decreased the chances
of sudden infant death syndrome or SIDS.
However, we also now know that the sleeping position
tends to be correlated with children crawling
at a somewhat later time.
And of course, this really doesn't matter
in the scheme of things.
And sleeping position doesn't affect
the development of later motor skills, like walking.
But it is an interesting way that our culture winds up
influencing motor development.
We also know that wearing diapers
can lead to children walking slightly later.
But to me, this seems like a small price to pay
for the convenience.
I suppose you could follow your child around all the time
or maybe cover your entire home in plastic,
but that sounds like a lot more work for not a lot of gain.
There are also a couple of patterns that you should keep
in mind when you think about motor development.
The first one is that we can break motor skills down into
two main types: gross motor skills and fine motor skills.
Gross motor skills are skills that involve larger muscles,
our arms and our legs.
While fine motor skills refer to movements
that involve smaller muscles, like our fingers.
So gross motor skills would involve things
like sitting up and walking.
While fine motor skills would be things like
cutting with scissors or coloring a picture.
And as you might expect,
large muscles like those in our arms and legs
tend to develop before small muscles
like the ones in our fingers.
Which explains why we can do things like sit up and walk
before we can hold a marker and color a picture.
Development also tends to move from the head to the toes,
which is why babies are able to lift their heads
before they can crawl.
And maybe you're a parent,
and you're wondering if there is anything
that you can do to speed up these motor milestones.
And the answer is, kind of.
As we mentioned earlier, certain actions
can't physically be done until the brain
and the muscles are ready for them.
But, once that child starts a behavior,
it is good to provide a lot of space and time
that will allow the child to practice.
Also, enriched environments with different kinds of toys
can allow for increased motor exploration,
which seems to speed up the rate at which
certain milestones might be achieved.
That said, I do want to stress that the research indicates
that it doesn't necessarily matter
and that children who are late in developing some skills
might be faster in attaining others.
And I also want to take a moment to point out,
any parents who may be watching this,
that they might want to appreciate the time
before their children develop motor milestones
rather than trying to speed them up.
Because once children start moving independently,
they don't really ever stop.
So enjoy the time that you have
when you can put an infant down and look away for a moment
while still being confident that the child will be
in the same spot when you turn back around.