Not to trying to be an 4$$hole but that sounds just like Stands.See JoJo's Bizarre Adventure part 3 with Kujo Jotaro[JoJo #3] to know what a stand is,or go to wiki.It is supposed to be your spiritual energy in the manga taking the form you have in your mind about yourself in the unconsious brain[the ID].Now as for real life,it is overreacting imagination that poeple get past during their lifetime.
If you still think about the whole "I hear things others don't think from time to time" or "See...etc" it's just you hearing noises you remember and it's part of the whole "day-dreaming"/absent-minded but with the ID getting on top of your concious self and let's you momentarilly "see" or "hear" things or if you have a huge imagination you might even hear things you'd never believe you'd hear[again the ID,but for this the concious self helps too sometimes] like : ex.[that hapenned to me] hear Vegeta speaking english but with Vegeta's Japanese voice.