"The gradual development of something from a simple to a more complex form."
It all started years ago because Ethan did not like bare feet, he needed them covered at all times. From this constant need to keep socks on, even while he slept, he developed stinky feet! So we got him slippers, but that died out, and we were back to constant socks. Slowly we advanced into the more complex pattern of development - his feet catching fire! To adapt to this he would immediately take his shoes off upon getting home, encourage all of us to do the same, and wander the rest of the day in his socks.
We, however, continue to evolve and recently we began witnessing a much more sophisticated, and more complex, pattern of behavior. We have categorized the routine as follows: he take his socks off only when he cuddles up in our bed. As a mechanism of protection and security he clutches his socks so as to not lose track of them, if he falls asleep. When aroused, so I can move him in his own bed, he, with closed eyes, will, in Braille-like fashion, feel for his socks, and put them on again prior to being led from our bed to his.
Some will say things could be worse. You're right. From this adaptation he has now developed the habit of wearing socks with his flip-flops. I'll tell you this evolutionary process could be worse, it could have mutated into wearing socks with Crocs!