The Familiarity Principle
 

People tend to develop a preference for things they have previously encountered, things they are familiar with. Social psychologists refer to this tendency as the familiarity principle. Given a choice between two similar items, one they have experienced before and another that is new, most people will choose the familiar item. This principle operates even when people are not conscious of their previous experience with an item. Once people have been exposed to an item – even if they do not recall having been exposed to it – they will tend to prefer that item over other items to which they have not been previously exposed.