When do humans reach the point in which they can make rational, and independent decisions as opposed to coerced, emotional, and or decisions that are influenced by external people

Question

I am preparing for a debate on voting rights. One of the topics is about either raising or lowering the voting age, and a key point is surely about brain development and the ability to have independent thoughts and make independent decisions, which typically you won't see in an 8 year old kid, or that even at age 21 you might still see some external influence in the type of decision one takes.

The question is to please give some academic references that deal with this situation, and if you can share your informed opinion, that's also valid.

Answer 1

Check out the Harvard research on the development of judgement and age 25.