Discuss the multi-store model of memory. Refer to the information above in your answer. [16 marks]
Most PIN codes are 4 digits long and are easy to remember. In contrast, mobile phone numbers are 11 digits long. Most people would not be able to remember a friend’s new mobile phone number unless they were able to say it to themselves several times without interruption. |
ESSAY HINT: Students must refer to the stem in their answer and should organise their response carefully. A clear structure of knowledge (AO1), application (AO2) and evaluation (AO3) works well. Students can explain the model’s stores and processes before applying this knowledge to the stem, in a single concise paragraph.
According to Atkinson and Shiffrin’s multi-store model (MSM), memory consists of three separate stores: the sensory register (SR), short-term memory (STM) and long-term memory (LTM). Each store differs in its coding, capacity, and duration. Information is transferred between the stores through attention, rehearsal and retrieval.
Information from the environment enters the SR through the senses. The SR consists of separate modality-specific stores, including the iconic store for visual information, the echoic store for auditory information and the haptic store for touch. It has a very large capacity but a brief duration: iconic memories last approximately 50 milliseconds to 2 seconds, whereas echoic memories may last for several seconds. Information that receives attention passes to STM, while unattended information is quickly lost through trace decay.
STM mainly codes information acoustically. It has a limited capacity of approximately 7 ± 2 items, although chunking can increase the amount of information held, and a duration of approximately 18–30 seconds. Maintenance rehearsal keeps information in STM for longer and, if prolonged, transfers it to LTM. LTM mainly codes information semantically, has a potentially unlimited capacity and may retain information for a lifetime. Through retrieval, information passes from LTM to STM, where it can be consciously used.
The information about telephone numbers illustrates the limited capacity of STM. A four-digit PIN falls within the average capacity of 7 ± 2 items and should therefore be relatively easy to remember. In contrast, an 11-digit mobile number exceeds this limited capacity, although grouping the digits into larger chunks may make it easier to retain. Repeating the number is an example of maintenance rehearsal, which keeps it in STM and may help transfer it to LTM. An interruption can prevent rehearsal and cause some items to be displaced from STM, reducing the likelihood of accurate recall.
One strength of the MSM is the substantial laboratory evidence supporting its different components. Baddeley found that STM primarily encodes information acoustically, whereas LTM primarily encodes information semantically. Jacobs demonstrated the limited capacity of STM, while Peterson and Peterson found that its duration is approximately 18 seconds when rehearsal is prevented. These highly controlled studies support different features of the stores described by Atkinson and Shiffrin. Jacobs’ findings also support the explanation of why an 11-digit mobile number is harder to remember than a four-digit PIN. Taken together, this evidence supports the MSM’s claim that STM and LTM are separate stores with distinct characteristics, thereby increasing the model's credibility.
Further support comes from the case study of Clive Wearing. After contracting herpesviral encephalitis, Wearing suffered damage to his hippocampus, an area involved in transferring information from STM to LTM. Although he could recall information from before his illness, he could retain new information for only 20–30 seconds and could not form lasting new memories. This supports the distinction between STM and LTM because his STM remained relatively intact while his ability to transfer new information into LTM was severely impaired.
Finally, the MSM may exaggerate the importance of rehearsal. Brown and Kulik documented “flashbulb memories”: vivid, long-lasting memories of emotionally significant events. For example, many people remember where they were when they heard about Princess Diana’s death or the 9/11 attacks, despite not rehearsing this information beforehand. This suggests that emotionally significant information can enter LTM without prolonged rehearsal, contradicting the MSM’s linear explanation of how memories are transferred.
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