It's always interesting to me that as a new statement from Snowden to the press comes out, most comments on Hacker News take him totally at his word, and assume that his interpretation of events and policy is by far the interpretation most likely to be true. Because I was already past Snowden's current age and current experience level in living in other countries by the time Snowden was born, I see a lot of holes and…
That's actually not an extraordinary claim. It is standard operating procedure to teach people in the military how to do this, and the techniques are widely known. Here is how my brother (who received this training before serving in Vietnam explained it).
The first thing to realize is that you will break. When you break, you will say whatever you think will make the torturer happy. Once you have broken, you will no longer know what reality is.
So be a wimp. Pretend to break early. Feed the torturer enough interesting false information (with some truth mixed in) to get them interested. When you break for real they will continue to ask about the false leads, and you'll tell them whatever you imagine they want to hear. Nobody - including you - will have any way to sort out truth from lies.
This is, of course, just theory for me. However I'm assured that it works. And our standard training procedures include practice being tortured to drill in the point.