Educated Trout , we have all heard or even quoted this expression. I think we may do this to give ourselves more kudos for fooling such an educated creature into taking our artificial offering.
Trout are not sentient beings , they do not think , they do not rationalise their actions. They life by instinct, they have a classic fight or flight reaction , if something appears natural they will eat it if it does not they flee, simples
Or maybe I’m wrong , check out this amusing link
http://www.womenanglers.us/Jimmy_smart_trout.html 
Jim
