Short-term memory
Short-term memory has a limited duration, and the contents decay over time. The decay idea is usually paired by the idea of repeating the memory over and over. In order to overcome the limitation of short-term memory, and retain information for a longer amount of time, it has to be repeated either by saying it out loud of by saying it mentally repeatedly.  By doing this the information will re-enter the short-term process and be kept for a further period.