According to the Stage Model, incoming information is processed through three distinct memory systems: Sensory Memory, Short-term Memory, and Long-term Memory. This model compares human memory to the working of a computer, where information is registered, stored, and manipulated.

The Sensory Memory is the first stage where incoming information enters. It has a large capacity and registers information from each of the senses with reasonable accuracy as an exact replica of the stimulus. However, it has a very short duration of less than a second. Examples include iconic (visual) and echoic (auditory) sensory registers, where information decays automatically.

Information that is attended to enters the second stage called Short-term Memory (STM). It holds a small amount of information for a brief period, usually 30 seconds or less. Information in STM is primarily encoded acoustically, i.e., in terms of sound. Unless rehearsed continuously, information may be lost from STM. It is fragile but not as fragile as sensory registers.

The Long-term Memory is a vast storehouse where all information acquired through learning and experience is kept. It is comparable to a computer's permanent memory (hard disk). Information can be retrieved and used from this system as and when needed.

Thus, information flows sequentially through these three systems, with each system performing distinct functions in processing and storing information.