Peterson and Peterson, 1959

Peterson and Peterson

1959

Aim

To investigate the duration of short term memory

Area

Short term memory, models of memory

Research method

True exp

IV- Time of intervals between learning and recall

DV- Number of correctly recalled trigrams

Participants

24 psychology students

Procedure

The participants had to recall trigrams, which are three meaningless constant syllables. They were presented one by one and had to be recalled in intervals of 3,6,9,12,15 or 18 seconds depending on the trail. None of the trigrams had two of the same letters. After hearing the trigram the participants were asked to countdown in threes or fours from a specific number until they saw a red light and then recalled the trigram. There was six trials in total.

Results

The results showed that the longer the participant had to count backwards the less accurate the recalls were. After 3 seconds, 80% was recalled correctly. After 6 seconds this fell to 50%. And after 18 seconds less than 10% of the trigrams were recalled correctly.

Conclusion

Short term memory has a limited duration of about 18 seconds when rehearsal is prohibited. If a person is not able to rehearse then the input will will not be able to be transferred to long term memory. Information from short term memory by memory decay.