[MeImCounting]

Theres actually a ton of different ways. The most obvious is probably MRIs of which many have been conducted with the subject having a huge variety of different stimulus. Then theres the good old fashioned behavioral studies ranging from the classic "does the subject jerk their hand back in the presence of heat?" to the more recent hungry judge phenomenon.

I wouldnt think the fairly self evident assertion that exterior stimulus changes both the internal state of a person as well as their behavior would be controversial.

At this point in history "free will" is really just the god of the gaps and those gaps shrink every year. Its probably a useful religious concept but as far as reality goes its the least interesting question one could ask about the whole human experience.

[mistermann]

Did you remember to check/contemplate whether your "measurements" are correct?

This seems like a rather recursively self-referential problem.

[MeImCounting]

Im not really sure what you mean here, could you elaborate?