All brain activity occurs spontaneously, automatically, in response to challenge.
The brain does not have to be taught to learn. To thrive, the brain needs plenty of stimulation, and it needs suitable feedback systems. Effective learning depends on emotional energy. When in trouble, people with intrinsic motivation search for novel solutions, whereas extrinsically motivated people look for external causes to blame for their failure. Too much stimulation, however, at any stage in life, turns a challenge into a threat.