It was proposed by Atkinson & Shiffrin (1968), it's a structural model of memory because it suggests that our memory can be understood in terms of different memory stores. The 3 proposed memory stores are:
1. Sensory Store (SS) - this receives incoming information from the senses and is modality-specific; that is info from every sensory system is encoded in the corresponding sensory format. Three types of SS have been investigated; iconic memory, for vision, echoic, for hearing and haptic memory, for touch. The duration of memories in SS is very short, and the capacity of SS is surprisingly large, with some information being remembered in its entirety.
2. Short Term Memory (STM) - this store receives information from SS and uses rehearsal to transfer info to LTM. It has a limited capacity of 7+/-2 chunks and items and a limited duration of 30 seconds. If information enters STM faster than it can be consolidated and transferred to LTM, then forgetting occurs by displacement. Much of STM is encoded in an acoustic form, although this is not the case for all STM functions.
3. Long-Term Memory (LTM) - this store has the greatest duration and capacity, but forgetting still occurs, at least we seen unable to access all of our memories. Encoding in LTM is semantic, this is when information is stored on the bias of meaning. Retrieval from LTM may use several mechanisms including various kinds of clues, such as context and state.
