The Atkinson-Shiffrin Model proposes that human memory can be separated into three main stores: sensory memory, short-term memory, and long-term memory. Sensory memory holds information for a very brief period of time (milliseconds), while short-term memory can hold a limited amount of information for around 18 seconds unless rehearsed. Long-term memory has a very high storage capacity and can hold information for days, weeks, months, or years.