Call out hooks are usually included in singles that are sent to radio station. I use to work in radio and almost every promotional single had them. It was usually a short snippet of the song's hook so you could hear how it sounds without actually listening to the whole song.
Here is a description I found on the net - "in market research to assist in gauging the popularity of a song by the recognizability of its hook".
its just a short snipped of the song. there are a few stones singles like that. the post above nailed it. sometimes radio stations would play this short hook when they would be hyping the premier of a new single so the listeners got a small sample. of course things like this don't happen on radio anymore