Ah, I see, that makes a little more sense. Can't say that I ever noticed any difference, but maybe that's just me. Or maybe it was the progression I did, from swimming underwater with no gear for some years (lots of neat stuff at the bottom of the pool or swimming hole), to getting my first mask and snorkel (and not always having both available at the same time, so I sometimes free-dived sans mask but with snorkel), to finally getting scuba-certified 35 years or so later (just a _slight_ delay from my originally intended schedule, owing to numerous detours along the way).
I don't remember any problems making the transition, but maybe it all happened so long ago that I've forgotten. It does suggest that those of us who believe a fair amount of free-diving/snorkeling training and experience should precede scuba training, are onto something. I was a fan of the YMCA's program for that reason, and why I also find SEI's approach (which was formed by ex-YMCA instructors, I believe) is what I think a proper scuba training program should be. But that's another issue which has been beaten to death here, and I don't want to restart that merry-go-round.
Guy
Interesting sidenote: I have never spent much time in the water - bad eyes, both -10 - so my swimming skills are not the best. You can't develop or hone technique if you don't actually do it. I can get from A to B, I can keep myself afloat no problem, but I centainly would not class myself as a strong swimmer.
When I did my OW, days shy of my 51st birthday, I started by buying a mask with perscription lenses. Did wonders for my comfort level.
I didn't break any speed records in the water, but I did manage the swimmimg test. Had no choice but to swim, as that was the only way I was going to get aboard the boat achored offshore LOL.
My brother, in the Navy, dragon-boater, sailing instructor, lifeguard, snorkler, spent his entire life in the water, did the cert with me. His idea, to which I first responded with laughter given my lack of comfort with not being able to see in the water. When I visited the DS with him and found out I could get a perscription mask, I was intrigued and decided to go for it.
All that is to say, he was a water baby and I was definitely not. He was a strong swimmer, me not so much.
I had less trouble with the mask skills than he did. Both confined and OW. Go figure.
BTW, I have since had laser surgery and am undertaking swimming lessons to build technique and endurance. All because I tried it and fell in love with it.
Of course, my 16 year old son who has been swimming and freediving from a very early age had no such issues. He just finished his cert several weeks ago and you would swear he has been doing it for years.
This is definitely an area where YMMV. I would suggest that for recreational diving, closing it off to people who do not already have all of that "other stuff" may prevent people like me from ever getting started (of course, some may think that is good although I obviously do not). But I feel safe in saying that having that experience before hand is no guarentee either.