Effects of encoding strategy, presentation modality, and scoring method on STM performance with the Peterson and Peterson technique.

The Peterson and Peterson (1959) STM experiment was replicated with variation of presentation modality and encoding strategy. The effect of various scoring criteria was also analyzed. The recall data showed that a Peterson and Peterson type forgetting curve was obtained using auditory presentation and instructions to rehearse vocally the trigrams when scoring only completely correct recall within the first 3 sec of the recall interval. With visual presentation and instructions to find meaningful trigram interpretations, the forgetting curve was higher and much more flat, especially when scoring position correct recall within the total 0-10-sec recall interval. In a buildup of PI experiment, no buildup of PI could be detected when visual presentation was used together with instructions to find meaningful trigram interpretations. The importance of the different encoding activities for recall performance was discussed.