Can synchronised tones facilitate immediate memory for printed lists?

In verbal list recall, adding features redundant with the ones to be recalled theoretically could assist recall, by providing additional retrieval cues, or it could impede recall, by draining attention away from the features to be recalled. We examined young adults' immediate memory of lists of printed digits when these lists were sometimes accompanied by synchronised, concurrent tones, one per digit. Unlike most previous irrelevant-sound effects, the tones were not asynchronous with the printed items, which can corrupt the episodic record, and did not repeat within a list. Memory of the melody might bring to mind the associated digits like lyrics in a song. Sometimes there were instructions to sing the digits covertly in the tone pitches. In three experiments, there was no evidence that these methods enhanced memory. Instead, there appeared to be a distraction effect from the synchronised tones, as in the irrelevant sound effect with asynchronised tones.