The participants are then asked to rate the song on a scale from "dislike very much" to "like very much". Top 40 stations typically can't wait that long for results and have participants "call out" directly, by listening and rating different hooks. Studies such as these inform the radio station how popular current songs are or if the audience is "burned out" of a certain song. Market research based on hooks gives radio stations of all genres awareness of what their audience demographic wants to listen to, and is even used to test the musical boundaries of the audience. Some groups even release these research hooks on a single's CD release. Scientific research A European consortium (including Utrecht University and the University of Amsterdam) studies the hook by using online games and the wisdom of the crowd to understand and quantify the effect of catchiness on musical memory. See also Catchiness Lick Refrain Vamp Theme Ostinato Earworm References Musical techniques