Murdock's serial position curve study (1962)

What was the aim of Murdock's study?

To provide evidence for the existence of separate short term and long term stores of the multi-store model of memory.

What was the study design?

- Laboratory study: control of extraneous variables

- Standardised procedures: replicability

- Pp's were 103 male and female Psychology students

What was the method of this experiment?

- 16 pp's were presented with a list of 20 words at the rate of 1 word per second

- After hearing the words, pp's were asked to free-recall all the words from the list they could remember, in any order

- They were given 90 seconds to recall the words

- The test was repeated 80 times over the course of a few days, Murdock used a different list of 20 words each time.

What were the results?

- The words as the end of the list were recalled first (known as the recency effect)

- Words from the beginning were also recalled quite well (known as the primary effect)

- Words in the middle of the list weren't recalled very well at all

- Murdock displayed his results in a graph called the serial position curve

What was the conclusion of the study?

- Murdock concluded that this study did provide evidence for the existence of separate short and long term stores:

the last words were recalled very well because they were still in the short term store, and so they were able to be readily recalled therefore proving evidence for the short term store (recency effect)

- The first few words were recalled well as there was time, at the beginning, for them to go through maintenance rehearsal as pp's would repeat them in their heads. This means they had passed onto the long term store, and so were able to be recalled therefore providing evidence for the long term store (primacy effect)

- The words in the middle were not recalled very well because they were in neither the short nor long term store

Positive evaluation for Murdock's study:

+ There is further support for Murdock's results:

- Murdock repeated the experiment again varying the number of words in the list as well as the presentation time and both the primary and recency effects were present

- Another study was conducted where a distractor task was completed after hearing the words rather than recalling them straight away. They found that the primacy effect was still present however there was no recency effect because the distractor task occupied the capacity of their short term store

- Also, case studies of amnesia also support Murdock's study, for example, HM and Clive Wearing

+ Murdock's study did provide evidence for the existence of separate short and long term stores in the multi-store model of memory

Negative evaluation for Murdock's study:

- The study lacked ecological validity as remembering words from a list isn't representative of what people use their memories for in real life

- Murdock's pp's were all the same age and profession so the results can't be generalised to the target population, which in this case is everyone. The results could have different if the sample was more representative. Also, Psychology students may figure out the aim of the study leading to demand characteristics which would decrease the study's reliability

- The conclusions were too simplistic - long term memory consists of 3 stores (episodic, semantic and procedural)