The FBI did a study on this years ago. But it was more to do with how the mind of a felon works, and how it can be used against them.
It was concluded that if a felon had a gun on you, and demanded money or something else, that a simple " no" would temporarily short circuit their thought process, because they " expect" full fear based compliance.
This could give you time to act before they recover.
However, this technique is no guarantee you will come out on top.