Hello!
The experiment this question refers to is Pavlov's Dogs.
Ivan Pavlov was a russian physiologist who is most known for his work with classical conditioning.
The system of checks and balances makes sure that one branch of gov. Doesn't get more powerful than the other by giving different powers to different branches. Like a certain branch can't do something without the "thumbs up" from the other branch. For example, the Executive Branch can veto bills from the Legislative Branch, but the Legislative Branch can override the veto. Hopefully that helped!!