The fact that some adults demonstrate limited thinking processes relative to other adults speaks to the important role of in cognitive development.

Education.

Explanation:

Just like when your muscle got stronger when you exercise regularly , your brain tend to perform on a higher level if you constantly put it to work.

Compared to non-educated adults, educated adults tend to be conditioned to constantly solve complex problems. In the long run, this will make educated adult have a higher cognitive skills compared to non-educated adults.

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