Elliot's getting bigger.  He is very strong.

Right now I can still lift him up, pin him down, force him into clothes, yank him out of jackets.  But it won't be long before my feeble biceps are unable to match his thigh and back muscles.

Which got me to wondering.  We think of mental and physical development as two parallel processes.  Muscle mass grows, and brain size grows, but they don't really have much to do with each other. Or do they?

Imagine an alternate universe, in which physical development proceeds normally, but brain development takes ten times as long (given the complexity of the brain, this isn't that implausible).

What would we end up with?  Kids who weigh 70 pounds but without the language skills to be reasoned with.  Kids able to punch you hard enough to break your nose, but without any impulse control.  Sounds like chaos. Not the best for the propagation of the species.

Back in our own universe, it starts to seem like maybe there is a connection between brain and physical development.  Maybe Darwinism doesn't allow a child to get so big that he can hurt himself until his brain is functional enough to handle the size.

Which means Elliot ought to be speaking fluent English any day now.