traditional four-stage model is far too simplistic … The Art of Thought, British social psychologist Graham Wallas, proposed that the creative process involves the following stages:
preparation, during which the creator acquires as much information as possible about a problem
incubation, during which the creator lets the knowledge stew as the unconscious mind takes over and engages in what Einstein referred to as “combinatory play”
illumination, during which an insight arises in consciousness—the natural culmination of a “successful train of association”
and a verification stage, during which the creator fleshes out the insights, and communicates their value to others.
“very superficial from a psychological point of view” 1950, J. P. Guilford