Research Study

Peterson & Peterson (1959)

Aim

The aim of the study was to investigate the duration of STM.

Procedures

They asked participants to recall strings of consonants (e.g. FBK) selected so as to be difficult to pronounce. Recall delay was set to 3, 6, 9, 12, 15 & 18 seconds during which rehearsal was prevented by participants counting backwards in threes from a target number (e.g. 397). Each subject was tested a total of 8 times at each of the 6 delay intervals.

The Peterson and Peterson technique has a number of positive features, including the very effective method used to prevent rehearsal. To see why, consider what the retention would be if this had not been used. However, the main criticism of the study is normally directed at their conclusion that forgetting from STM is due to decay. In fact, interference (retroactive) from the verbal counting task is just as likely an explanation of the forgetting.

Findings

The findings of the study showed that while after a 3 second retention interval trigrams about 90% of trigrams were recalled, after 18secs only 10% were. The duration of STM without rehearsal is therefore very short.

Evaluation

The Peterson and Peterson technique has a number of positive features, including the very effective method used to prevent rehearsal. To see why, consider what the retention would be if this had not been used. However, the main criticism of the study is normally directed at their conclusion that forgetting from STM is due to decay. In fact, interference (retroactive) from the verbal counting task is just as likely an explanation of the forgetting.

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