In reply to nniff:
> (In reply to CurlyStevo)
>
> Well, there was another 'academic' study that showed the opposite, despite what everyone observed to the contrary.
>
> Now that we have a study in each camp, the planets are once again in harmony...
Yup, on the one hand we have
http://www.ncbi.nlm.nih.gov/pubmed/23259237, but on the other hand there is
http://www.ncbi.nlm.nih.gov/pubmed/11411778. The first says chalk increases coefficient of friction between hand and rock, the second says it decreases coefficient of friction.
The first found no effect for humidity, which anyone who has climbed the same moves in humid and dry conditions knows to be false. The second found no effect for actual wetness, which is preposterous.
Of course, the testing protocols were different, and each has aspects that could be criticized Moreover, it is arguable whether the concept of coefficient of friction even applies to contact between skin and rock.
One of the things not tested was the amount of chalk. Many years ago, physicist John Stannard (American clean-climbing pioneer and historical contributor to Gunks difficulty standards) performed his own tests (the mechanism was pinch-gripping various rock types with increasing weight applied). His results were that a very light dusting of chalk increased coefficient of friction but a heavy application decreased it. Stannard did this 40+ years ago and published it in his climbing newsletter, The Eastern Trade. It is interesting that all these years later, investigators have not considered whether the amount of chalk used determines whether grip is increased or decreased.
Stannard's observations led him to "invent" the chalk sock, which only dispenses a light dusting. The sock has the added advantage of not covering a climb in ugly white connect-the-dots hold markers, or at least requiring far more ascents before a climb reaches that hideous but now commonplace condition. And of course there is the advantage of not dumping an entire bag of chalk on the ground when you sit down.
Most climbers are so addicted to slathering chalk on that they cannot get used to the light dustings of the chalk sock, which never really caught on. And most climbs are now permanently marked by chalk, meaning that anyone starting out in the sport considers that the climb's "natural" state anyway.