the primary effect is the term used to mean that people often remember the first thing they are told. many psychologists think that this effect may be a result of rehearsal. when a person is trying to remember the items, that person will often repeat the items to themselves. as each item is added to the list, they repeat the entire list. this causes them to repeat the first it many time. this constant repeating helps them to better remember the items at the begining of the list,the slower the list is presented, the more time a person has to repeat the list. this causes a larger primacy effect.