Effects of recurrent tonal information on auditory working memory for pitch

This study ascertained the influence of repeating pitch information within an intervening tonal sequence upon the extent of interference for a pitch standard held within auditory working memory as measured by the difference limen for frequency (DLF). Standard and comparison tones were presented to subjects and same/different responses were obtained using a touch screen monitor and the DLF was measured using single interval adjustment matrix (SIAM) procedure [Kaernbach, C., 1990. A single-interval adjustment-matrix (SIAM) procedure for unbiased adaptive testing. J. Acoust. Soc. Am. 88, 2645-2655]. Estimates of the DLF were obtained in a control condition with a silent inter-comparison interval and three conditions containing intervening tones within the temporal gap between the standard and comparison stimuli. The presence of intervening stimuli produced a significant increase in the DLF when the intervening tonal sequence contained tones with pitches that differed from that of the standard (Int condition) as well as when the sequence contained a tone with a pitch identical to that of the comparison (RptCmp condition). Further, the DLFs obtained for RptCmp condition were significantly higher than those measured in the Int condition. The DLFs measured in the condition where the pitch of an intervening tone was identical to the standard were significantly lower than those for the Int and RptCmp condition, but did not differ from the DLFs for the control condition. These results indicate that either a release from or an increase in interference in auditory working memory for pitch can occur dependent upon the frequency relationships between of the standard, comparison, and intervening tones.