The Atkinson–Shiffrin model (also known as the multi-store model or modal model) is a model of memory proposed in 1968 by Richard Atkinson and Richard Shiffrin. The model asserts that human memory has three separate components:
Since its first publication this model has come under much scrutiny and has been criticized for various reasons (described below). However, it is notable for the significant influence it had in stimulating subsequent memory research.
The modal model of memories is an explanation of how memory processes work. The three-part multi-store model was first described by Atkinson and Shiffrin in 1968, though the idea of distinct memory stores was by no means a new idea at the time. William James described a distinction between primary and secondary memory in 1890, where primary memory consisted of thoughts held for a short time in consciousness and secondary memory consisted of a permanent, unconscious store. However, at the time the parsimony of separate memory stores was a contested notion. A summary of the evidence given for the distinction between long-term and short-term stores is given below. Additionally, Atkinson and Shiffrin included a sensory register alongside the previously theorized primary and secondary memory, as well as a variety of control processes which regulate the transfer of memory.
Following its first publication, multiple extensions of the model have been put forth such as a precategorical acoustic store, the search of associative memory model, the perturbation model, and permastore. Additionally, alternative frameworks have been proposed, such as procedural reinstatement, a distinctiveness model, and Baddeley and Hitch's model of working memory, among others.
When an environmental stimulus is detected by the senses it is briefly available in what Atkinson and Shiffrin called the sensory registers (also sensory buffers or sensory memory). Though this store is generally referred to as "the sensory register" or "sensory memory", it is actually composed of multiple registers, one for each sense. The sensory registers do not process the information carried by the stimulus, but rather detect and hold that information for use in short-term memory. For this reason Atkinson and Shiffrin also called the registers "buffers", as they prevent immense amounts of information from overwhelming higher-level cognitive processes. Information is only transferred to the short-term memory when attention is given to it, otherwise it decays rapidly and is forgotten.