The Multi model store of memory

Atkinson and Shiffrin claimed that memory is made up of three different stores - sensory register, short-term memory and long-term memory. Short term and long term memory are unitary stores but sensory register is modality specific ie it has different types of memories associated with each of our senses. Information has to be processed in a fixed order.

Information goes to sensory register first then STM and finally LTM.

Sensory Register

The sensory register contains information from the senses for example visual information is

¡conic memory and auditory information is echoic memory. Duration of information in the SR is very brief - around 0.25 seconds but the capacity is very large. If a person's attends to this sensory information then it is transferred to STM, if not attended to then the information is lost through decay.

Short term memory

Once the information passes to STM it is converted to an acoustic form (encoding) so that it can be temporarily stored there. Information can be stored in STM for around 18 seconds unless that information is rehearsed, so information can be lost through decay.

STM also has a limited capacity and can hold between 5 to 9 bits of information when the capacity has been reached, new incoming information will be lost through displacement.

Information is transferred to LTM through a process called rehearsal. The model places emphasis on the importance of rehearsal:

It acts as a buffer between sensory memory and LTM by maintaining in coming information within STM!

It enables information to be transferred to LTM.

Long term memory

When information passes into LTM it is then encoded into a semantic format so thatit can be stored. LTM is thought to have an unlimited capacity and information can be stored for a lifetime. it is thought that there are no storage limits.

Evaluation

There is brain scan evidence to support the idea that there are separate memory stores as the model suggests

Research that has used brain scanning techniques has discovered that there are indeed different areas of the brain activated when performing tasks that use the STM and the

LTM. Beardsley (1997) found that the prefrontal cortex is active during STM but not LTM tasks and

Squire et al (1992) found that the hippocampus is active when LTM is activated but not

STM. This research suggests that there are distinct areas of the brain that we use when performing tasks that require us to use or STM which are different from when we use our LTM. This evidence is consistent with the idea that STM and LTM are separate and distinct stores as the evidence points towards these structures being different areas of the brain.

Furthermore, Shallice and Warrington (1970), reported the case of KF, who was brain damaged as a result of a motorcycle accident. His STM was severely impaired, and he could often recall only one or two digits on a digit span test. However, his LTM for events occurring after the accident was normal. This supports the view that STM and LTM are separate and distinct as the model suggests.