VIRII said:There is various evidence in books regarding Auschwitz etc, I believe also in some of the more recent SAS books where certain ex soldiers have spoken about things they have experienced.
I have no direct links I am afraid but as I understand it some people have managed to withold info under torture and survived. At the end of the day if the torturer believes that the prisoner doesn't really know what he needs to know I guess he'll concentrate on someone else.
If you want a good book on Systematic torture then read Fire Under the Snow by Palden Gyatso
Some Brief Info Here
Imprisoned in 1959 by the Chinese after the occupation of Tibet. Freed in 1992. Not a pleasent read I will be honest . During this time his spirit was never broken but it charts years of systematic physical and psychological torture by a variety of methods.
A good read none the less