The instructor of the local Hunter Safety course opined that deer don't like to eat where they poop. That deer do poop in the process of eating and as they wander through the woods. Ergo, long established corn feeder locations will become contaminated over time with deer, rat, coon, dove, hog, turkey, et al, feces and the deer will avoid the "free food".
This then is not unlike the "learned" behavior of avoiding food plots, which are hunted hard. It can be decerned by deer that MaryJo, Jackie, and Erma Doe are no longer in the herd as a direct result of eating from yonder garden. Farmers, on the other hand, will disagree, and I believe that is the direct result of the proponderence of readily available food in the plots.
Try hunting a small plot in the woods and in short order you will see what I mean.