Thoughts ascending

Overheard conversation this morning...
J and M are discussing how the kids seem to stratify into higher level critical thinkers, mid-level thinkers, and an unfortunate bottom few for whom higher-order thinking seems to fly far above their heads. Then out of the blue, the following improvised dialogue emerges:

J: Me hungry.
M: That's the lizard brain functioning.
J: Me want eat meat!
M: That's the brain starting to make rudimentary decisions.
J: Meat taste good!
M: Now the brain is making value judgments.
J: Me think me have headache!
M: Ah, now you're thinking about thinking. Your brain is becoming metacognitive.
J: That just blows my mind!
M: And now you're able to appreciate aesthetics and abstractions.

J and M dissolve into laughing fits at that point (yes, GP tutors have a very strange sense of humour), but I'd like to add the next line to the conversation, just to round things out:

J: Wow! Wait till I tell mommy!
M: And now you're finally living outside of yourself! Sharing information is probably the highest level thinking ability of all.

So, is it true that each of us maxes out at a particular intellectual potential, or are all of us capable of thinking more than a penny's worth of thoughts?