The problem with that is that "fully developed" is a meaningless phrase.
There is no fully developed - as I wrote in my earlier comment, it keeps developing for a persons entire life. There is no point where it stops.
Another problem is that this type of development is more influenced by environment than it is by age. So using age as a cutoff because of "developed" is silly - that's not the thing that matters the most.
> The problem with that is that "fully developed" is a meaningless phrase.
Even if that were true, that would justify pointing that out and/or seeking clarification, not simply making up your own strawman to argue against because the person you wanted to argue against hadn't posted something for which you had a canned argument handy.
Its also not really true; while "fully developed" may be somewhat imprecise, its a fairly decent non-technical characterization given the research showing the course of physical development of the relevant brain centers and how they track with age.
There is no fully developed - as I wrote in my earlier comment, it keeps developing for a persons entire life. There is no point where it stops.
Another problem is that this type of development is more influenced by environment than it is by age. So using age as a cutoff because of "developed" is silly - that's not the thing that matters the most.