Do you have any proof of that?
If you mean laboratory type studies performed under controlled conditions, no. I doubt if there ever can be such a thing, given different people's different reaction speeds.
But having said that, Jeff Cooper, Massad Ayoob, Chuck Taylor, and numerous others have found it to be the case.
I have found it to be the case, and I have carried double action revolvers, DA/SA autos (my first police department-issued handgun), DA only autos (my second department-issued handgun), and the Glock, with its sort-of-double-action-only trigger. There is nothing I can get an accurate first shot off, or accurate rapid follow up shots with as fast as I can with a 1911. And finally, there is a reason that the 1911 dominates in competitions where speed out of the holster and speed at hitting targets is paramount.
All in all, it rather seems as though you are asking me to prove the sky is blue.
None of this is to say you can't be incredibly fast with a different gun if you have the skill. Bill Jordan, for example, was blindingly fast with the double action revolver that he preferred -- probably faster than 99.9% of 1911 shooters. The shooter, more than the handgun, is the critical factor. But all things considered, the light, short, and consistent pull of the 1911, along with its short reset, is a decided advantage, which is why so many people still choose it over anything else.