Question about what is used in admissions

I have a question that I’m hoping could be answered by one of you guys. An answer from @MITChris would be great.

I’m essentially wondering to what extent, if any, AP scores are used in the admissions processes at MIT - and other schools.
Could a 1 hurt someone? Could a 5 help someone? Considering they still got an A in the class.

If it does have an impact, what is the score that is neutral and has no positive or negative impacts?
is it a 3? a 4?