Summary Of Experiment 1 Murrdock

Experiment 1
In experiment 1 Murdock (1962) was attempting to explain two things: how lists varying in different presentation rates would affect the serial position curve and how different list lengths would affect the curve. Lists fluctuating in different presentation rates of either 1 or 2 seconds and list lengths of 10,20,15,30 and 40 words were given to six groups where group testing was used. After every list a recall period of 1.5 minute was given and participants were told they could recall in any order they wanted (free recall). The participants consisted of 103 psychology students from and introductory psychology class. The method was an experimental design with repeated measures. The independent variable was the serial positions of

Subjects where tested individually and shown words for 1 second with a 2 second interval in between. After the experimenter had read each word aloud a symbol of a crosshatch, or a digit from 0-9 was shown. If the crosshatch symbol was presented subjects were able to recall immediately but if a number appeared the subject was to count backwards until the experimenter told them it was okay to recall. As subjects where participating in the distractor task the experimenter would time either 10 or 30 seconds before telling them to write. The independent variable was the amount of time after the list the subjects had to wait to recall, 0, 10 or 30 seconds. The dependent variable was the ability of recall produced. Participants were given a maximum time of 5 minutes to complete recall. The results indicated that “the 10 second delay was sufficient to remove most of the end peak. With a 30 second delay there is no trace at all of the end peak” (Cunitz & Glanzer, 1966). The larger the delay the harder to recall because your attention is now distributed elsewhere. For each delay the primacy effect was relatively the same but when a subject had to wait longer to recall by doing the distractor task of counting backwards their accuracy of recall of later words effected the recency effect. Words at the end of the list are still being rehearsed in short-term memory which means they are available to recall with ease and therefore account for the recency effect nut once a delay occurs the information will decay quickly. The manipulation of short-term memory influenced the recency effect but had minimal effect on primacy. Both of these experiments further support the findings that output from both long-term and short-term effect the serial position