Since I’ve gathered some data on the topic in the past, I am going to link to a Lucky Gunner article about using the sights on a pistol.
I did an experiment years ago in which 10 different experienced shooters tried point shooting a single round at a silhouette starting at one yard. Then the distance was increased one yard at a time for the group. To test whether some form of visual indexing to the pistol was necessary, each shooter had a piece of cardboard placed horizontally in front of him at neck level so there was absolutely no visual reference to the pistol’s orientation. There was no time limit, the shooters were free to adjust their pointing until they thought they were on target.
The bullets starting hitting the ground at two yards. Only one shooter was able to make a hit anywhere on the silhouette at 5 yards and that was a peripheral hit. I discontinued the experiment at that point.
I figured out everything I needed to know about hitting a target without visual reference to the gun and with the gun below the eye-target line from that experiment.
Using the sights (i.e., getting the pistol into the eye-target line) is how we learn to kinesthetically index the handgun. Ask someone to point their finger at any object. Notice they don’t do it outside of their ‘workspace’ the more or less basketball sized space in front of the chest, properly called the ‘ipsilateral visual field.’
We may not always use the sights in a fight but training with them is how we learn to correctly index the pistol kinesthetically.
tacticalprofessor 
Glad to you posted your experiment here. Too many people just don’t understand how that works!
Interesting experiment. Proves the maxim: you can’t hit what you can’t see. May I recommend “Hitting in Combat: The Brain Science of Training to Win Gunfights” by Dustin Salomon. Salomon presents an interesting case for why learning unsighted shooting before learning to use the sights may prevent you from being able to use your sights under stress. I would be interested in responses from anyone who has read his book. You might also check out Kyle Lamb’s podcast a couple weeks ago where his guest was Dustin Salomon and they discussed this book.
I will have to czech out Salomon’s book. I wonder if it’s based on the Hocking College experience that students who learned FSA point shooting first could never really adjust to using the sights under any conditions.
I don’t think Salomon referenced the Hocking College experience, but his thesis is the same, just from a different perspective. I found plenty about Hocking’s point shooting classes from the past, but no references to not being able to use sighted fire after learning point shooting. Do you have a reference? Thanks.
Paul Gomez knew one of the instructors. He related to me that after teaching the FSA class for two years, the college had to make the sighted fire class a prerequisite for the FSA class. Students who started with FSA had great difficulty passing the standards for the sighted fire class but the reverse was not true.