I have a theory that children reach a high level of mental capability very quickly. What they lack is experience and an adult level of language facility. I think it's a very good idea to speak using easy to understand language when talking to children. However, I also think it's a good idea to expect that they have very good reasoning ability if given enough information.
Some level of infantilising is not necessarily a bad thing. I definitely was not equipped mentally to be able to overcome the things I am dealing with in my 20s. Was I any less smart when I was 11? Probably not; but now I have other skills and traits apart from intelligence. Work ethics, sense of responsibility, and empathy to name a few.
Giving kids too much responsibility or credit does not help them further down their lives, but at the same time disregarding them entirely because they're kids will do irreparable damage to their self esteem.
"Was I any less smart when I was 11? Probably not;"
For reasonable definitions of "less smart", yes, you were. There's a lot of work on child development, and it does not support the idea that an 11-year-old is as fully equipped as an adult. Piaget's child development stages is an accessible overview if you want a nice Googleable term. Modern academics would quibble with various aspects but from what I can see a lot of the general ideas one would get from a quick breeze-through are still a reasonable start.
I'm actually pretty close to first in line to say that we underestimate children... buuuut, at the same time, no, they are not just little adults that are getting suppressed by The Man or whatever. They really aren't anywhere near fully developed yet, and are as a population, generally incapable of many things no matter how hard you tried to push them. And even if you do find an individual 11-year-old that, say, is fine with calculus, in another 10 years they'll be even more developed.
Absolutely. Then puberty hits and the brilliance seems to take a huge dip. I guess obsessing about sex takes a lot of brainpower. Just a hypothesis though.
According to The Male Brain, by psychiatrist Louann Brizendine, males have 2.5x the space devoted to sexual drive in the hypothalamus compared to females.
By the time males reach puberty, guy’s sexual occupation and fertile female tracking circuits run in the background non-stop like an unkillable daemon process.
Speaking personally, I feel that the experience of sexual attraction and sexual desire has been a stimulus to the development of my intelligence, not a brake upon it. If you look at great art and literature you will see it has played a crucial role there too. So no, I don't think it is a 'sensible hypothesis'.