Peterson and Peterson investigated one of the factors that causes our short-term memory to decay, i.e. why we forget information in our short-term memory. In 1959, they conducted an experiment that revealed how time between remembering something and having to recall it affected the life of a memory.
What is at Trigram, and why use it? |
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Peterson and Peterson showed participants a trigram - a set of 3 consonant letters, such as ADW. This method would be known as the Brown-Peterson technique, and can be used to remove a number of factors that might affect someone's memorization of a piece of information: 1) The trigram has little or no meaning, unlike asking a person to remember a word which they may associate with something and be able to remember better. 2) There are no vowels in the trigram, preventing any easy pronunciation of the trigram as a word, which makes it more difficult to remember on any other basis than as a trigram. 3) Unlike words, the trigrams are equal in length, making the experiment less biased in terms of the information it requires participants to remember. |
In the experiment:
Recall success was around 50% after an interval of 3 seconds
and interference task, but this reduced gradually to around 10% over intervals
of 6, 9 and 12 seconds, and gradually to around 5% success after 18 seconds.
This suggests that time does result in decay in the short term memory.
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Peterson and Peterson were careful to eliminate factors other than time that might affect recall: Interference tasks reduced the chances of rehearsal before recall.
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In addition to this trigrams were used to eliminate the attached meaning that might be used to remember, for example, words, better. |
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Lacks ecological validity - how often is a person needed to remember trigrams in reality? |
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