Age equivalence in auditory distraction by changing and deviant speech sounds.

The present study was designed to examine age-related differences in the disruption of short-term memory by changing and deviant speech sounds. In total, 128 old and 130 young adults performed a serial recall task while ignoring (a) steady-state sequences in which the same distractor word was repeated 12 times, (b) auditory deviant sequences in which the ninth distractor word deviated from the otherwise repetitive context, and (c) changing state sequences in which 12 different distractor words were presented. According to inhibitory deficit theory, older adults should generally be more susceptible to auditory distraction. The duplex-mechanism account of auditory distraction is based on the idea that the changing state effect and the auditory deviant effect are functionally different. It suggests that older adults should be more impaired by auditory deviants than younger adults but equally able to ignore changing state sequences. The age-invariant distractibility account predicts no age differences in auditory distraction, which was confirmed by the present results. Old adults performed worse than young adults in the serial recall task. In both age groups, however, the changing state effect (i.e., increased disruption by changing state sequences relative to steady-state sequences) and the auditory deviant effect (i.e., increased disruption by auditory deviant sequences relative to steady-state sequences) were equivalent. These effects were also unrelated to individual differences in working memory capacity. [ABSTRACT FROM AUTHOR]