Short-term memory is a type of memory that lasts for about 15 to 30 seconds and can be extended through rehearsal. It is different from long-term memory, which can hold information for longer periods of time and has a larger capacity. According to Miller (1956), short-term memory has a capacity limit of about seven items, which can be increased through the use of "chunks." Without rehearsal, information in short-term memory is quickly forgotten. This type of memory is often referred to in psychology as the limited capacity to hold a small number of items in mind.