Please, by all means keep your beanies on and I will do the same, but let's not do so out of ignorance. I believe the 1957 study you link to is the same one referred to here:

"Dr. Daniel I. Sessler, an anesthesiologist and expert on hypothermia at the University of Louisville medical school, said the popular myth stems from military experiments conducted five decades ago."

The popular myth being the 50% figure. I'm certain at the time, they were using the best techniques and instruments available such as they were. If you want to base your survival decisions on outdated data from 1957 while ignoring the current 10% figure from todays experts, go right ahead...just don't invite me on your next 2 week backcountry campout (yeah, likes that's gonna happen