Excellent summary on Farnam Street.
Simplicity starts as a beginners view of the world, experienced but unaware of the depth. Here there is a sense of wonder.
To Complexity where there is a sense of depth but with few clear patterns arising to help. Here there is a sense of 'overwhelmed'.
To Informed Simplicity of the high performer and expert. Real-time synthesis and pattern recognition making the important stand out as important. Here lives wonder and flow.
This is trainable in growing experts.