Is this why people can't see certain spren?
If one person's "cognnitive ideal or concept" of the poo is that it is disgusting and smelly then would the spren he sees would be more akin to stink lines, while his Coprophagic dog, who quite fancies a good poo, would see different spren that look like gumdrops, lollipops, and other assorted candies?
No, wait, that would be ridiculous... candy is people food! Perhaps sheep then?
(and on a more serious note, what does this mean about people like Rock who can see all spren? Wouldn't he have to have the same ideals as Kaladin? Maybe there is another type of magic we don't know about yet, that allows him to read peoples minds, or maybe I read something wrong and don't actually know what I'm talking about, and should have stuck with the poo eating dog?)