Murdock (1962)

Multi-store Memory Model

Aim

To investigate if the length of a list of words and/or the pace at which the words were read would have an effect on the serial position curve

Research Method

Experiment

IV

Length of list, pace at which the list was read (6 conditions)

DV

Number of words accurately recalled

Procedure

Participants were read a total of 80 lists of words of varying lengths (10-40 words) and at varying paces (1/2 sec intervals) across 4 sessions spaced between 2 and 7 days apart.

After each list was read, the participants were given 1.5 minutes to recall the words in any order.

Findings

1) Probability of accurate recall depends on its serial position: words presented at beginning & end were more often recalled, but words in the middle were more often forgotten. 

2) The pace of the presentation did not make a difference

Conclusion

The fact that words presented either early in the list or at the end were more often recalled, but the ones in the middle were more often forgotten supports the idea of multiple stores. The words from the end of the list went into STM, which can typically hold about 7 items for up to 30 secs, and this is referred to as the ‘recency effect’. The words at the beginning were rehearsed the most and thus went into LTM, and this is referred to as the ‘primacy effect’.

The words held in the middle had been there too long to be held in the STM, and not long enough to be put into LTM, and were thus forgotten. Recalling information is therefore from two separate stores (STM and LTM), otherwise each of the words should have had an equal chance of being recalled.

These results also support the assumption of the MSM that STM has a limited capacity. As new words were introduced it is most likely that the capacity was exceeded and so the middle words were displaced i.e. new information pushed out the old The capacity must be limited otherwise the words in the middle would not have been forgotten.