Short-term memory (or "primary" or "active memory") is the capacity for holding, but not manipulating, a small amount of information in mind in an active, readily available state for a short period of time. For example, short-term memory can be used to remember a phone number that has just been recited. The duration of short-term memory (when rehearsal or active maintenance is prevented) is believed to be in the order of seconds. A commonly cited capacity of items to remember is "The Magical Number Seven, Plus or Minus Two" (also called Miller's Law, despite Miller calling the figure "little more than a joke" (Miller, 1989, page 401)). Cowan (2001) suggests that a more realistic figure is 4±1 items). In contrast, long-term memory holds information indefinitely.