Let me randomly list some of the things I have found:
Students have had distracting side-thoughts provoked by some detail in the story
One student once turned the story into a film in a foreign language, with subtitles in his language and with a strong musical soundtrack. ( amazing) ( The story was set in this foreign country)
Another person was reminded of another story they already knew and fused this story with the story I was telling.
Students drift out of the telling for some seconds and miss a whole bit as they thinking of something quite else.
Students sometimes get small, black and white still pictures in their minds as I tell.
There are students who get no pictures and have strong feelings...they tend to know the temperature and the weather in the story.
A few students wonder about the narrative plot and where it is leading.
Students who like the story will often get vivid colour pictures at the beginning and then mentally find themselves in the same space as the action, like in a dream.
Occasionally a student will become so associated that they become the protagonist of the story.
Occasionally a student will start noticing the story telling technique and the use of voice.
I could go on listing listener behaviours but the above suffice to give you some idea of the complexity of what is going on in student heads as they listen to a story.
Knowing what I do, how can I possibly dream of insulting these sub-consciously brilliant folk with absurd "comprehension questions" about my original text that has been fully superceded by theirs.
Warmly yours, Mario