Aim: To investigate the duration of short-term memory, and provide empirical evidence for the multi-store model.
Procedure: A lab experiment was conducted in which 24 participants (psychology students) had to recall trigrams (meaningless three-consonant syllables, e.g. TGH). To prevent rehearsal participants were asked to count backwards in threes or fours from a specified random number until they saw a red light appear. This is known as the brown peterson technique.
Participants were asked to recall trigrams after intervals of 3, 6, 9, 12, 15 or 18 seconds.
Findings: The longer the interval delay the less trigrams were recalled. Participants were able to recall 80% of trigrams after a 3 seconds delay. However, after 18 seconds less than 10% of trigrams were recalled correctly.
Conclusion: Short-term memory has a limited duration when rehearsal is prevented. It is thought that this information is lost from short-term memory from trace decay. The results of the study also show the short-term memory is different from long-term memory in terms of duration. Thus supporting the multi-store model of memory.
Criticisms: This experiment has low ecological validity as people do not try to recall trigrams in real life.
Memory is involved in processing vast amounts of information. This information takes many different forms, e.g. images, sounds or meaning. For psychologists the term memory covers three important aspects of information processing: Encoding, storage and retrieval.