 The mere exposure effect is a psychological phenomenon by which we tend to like things merely because we are exposed to them. So simply exposing you to a random thing repeatedly makes you like it and the same goes for pop songs, products and people with the exception of those we dislike initially seeing them more often can make us dislike them further. Known for discovering the effect was psychologist Robert Zients who had noticed that organisms exposed to something new experience fear. Each subsequent exposure to that new thing causes less fear and more interest and with more exposure the observer begins to react fondly to the once novel stimulus. Using a tachistoscope and a group of people he exposed each person to a series of random shapes that changed so quickly that it was impossible to discern that some were repeated.