According to Phillip G. Armour
The trick with managing accelerated learning is getting people as far as possible into the anxiety region without them shutting down. Some organizations are very good at doing this. The U.S. Marine Corps brings its recruits into the Parris Island and San Diego depots at 2:30 in the morning for a reason. They intentionally stress the recruits and push them way into the anxiety region because it is there that they learn the most. Specifically, it is there that they learn how to be U.S. Marines. The Outward Bound school uses a similar, albeit less extreme, approach when it takes at-risk teenagers out into the backwoods and wilderness and places them in a challenging and stressful environment where they can learn the self-respect and self-confidence they often lack. Both organizations freely acknowledge that learning, particularly accelerated learning, is not a “comfortable” activity.
The comfort zone is a no learning zone.
There’s no learning in the comfort zone. If you’re comfortable, you’re not learning.