Intonation and positional effects in spoken serial recall

Past studies have indicated that intonation, in the sense of fundamental frequency modulation, can only enhance serial recall to the extent that it can induce a grouping effect, something that can also be induced by a simple insertion of pauses. However, in a study of spoken serial recall of ninedigit lists, we are able to show that recall is significantly better when sequences of digits are marked by specific intonation contours than when they are simply grouped by silent pauses in the signal. Thus, we found that intonation plays a role during the encoding phase, whereby items in group-final positions draw particular benefit from intonation. However, intonation does not appear to play the same role in the retrieval phase, since when subjects are instructed to imitate intonation during recall, performance shows mixed effects.