Phonemic interference in short-term memory contributes to forgetting but is not due to overwriting

Six experiments are reported which examine the pattern of interference created by phonemes being repeated across items in a short-term memory task. Experiments 1 and 2 utilised a serial recall task and demonstrate that when the three phonemes of a target word are distributed across other words in the list, recall of the target word suffers when the distributed phonemes are presented before the target in the list, but not if they occur after the target. Experiment 3 demonstrated that the interference was not a result of rehearsal processes during list presentation, and Experiment 4 replicated the results in a within subject design. Experiments 5 and 6 showed that the interference effect was not due to weaker encoding of the target words when they followed the interfering words by manipulating the order of item recall. It is argued that this phonemic interference occurs at output through a spread of suppression of activation from the recall of earlier list items.