I remember long ago something about a critical time for learning. I looked some and found http://en.wikipedia.org/wiki/Critical_Age_Hypothesis. This is in speech. "The hypothesis claims that there is an ideal 'window' of time to acquire language in a linguistically rich environment, after which further language acquisition becomes much more difficult and effortful."
I propose something similar. There is an ideal window of time to acquire any skill that has accompanying neuronal development. As a neuropathway is made, the skill is acquired and becomes refined.
To illustrate, the following pictures are of me performing "Pucker" and "Smile", exercises 2,3, and 4 of http://braininjuryknow.blogspot.com/2010/11/oral-motor-exercises.html. This my Pucker at first:
I had stopped doing the Oral-Motor Exercises after talking. I had "acquired" the skill, but not refined it. It had already taken a long time to acquire, and much more (refinement) didn't appear to be happening. Recently, I felt I may be in a "critical window" by the results of other skill development. I performed those exercises (20 reps. a day) for a week. If I wasn't in a "window", then nothing. I was amazed with the following:
This is a picture of me performing "Pucker" after a week of exercise There is more muscle tone in the area around my mouth. You can specifically see a crease starting that goes from my nose to my mouth on the left side of the picture.
I only suspected I would get this result as other areas have been doing the same. I remembered a little bit of that theory and looked. I found it only covered speech, but I see it in other areas. I see it in a cognitive test I perform regularly. I'd venture to say it is responsible for the gross motor jump from pushing up to standing http://www.flickr.com/photos/angelar70/sets/72157626815593901/
This shows that there is a critical window of time to acquire any skill that has accompanying neuronal development. (There has been accompanying neuronal development and I refer you to http://spiritualscientific.com/DrMorseBlog/category/remarkable-people/angela-ronson-remarkable-peo.%20ple/.)
*I don't want this confused with Speeh, so