Deviant as well as changing auditory distractors interfere with short-term memory. According to the duplex model of auditory distraction, the deviation effect is caused by a shift of attention while the changing-state effect is due to obligatory order processing. This theory predicts that foreknowledge should reduce the deviation effect, but should have no effect on the changing-state effect. We compared the effect of foreknowledge on the two phenomena directly within the same experiment. In a pilot study, specific foreknowledge was impotent in reducing either the changing-state effect or the deviation effect, but it reduced disruption by sentential speech, suggesting that the effects of foreknowledge on auditory distraction may increase with the complexity of the stimulus material. Given the unexpected nature of this finding, we tested whether the same finding would be obtained in (a) a direct preregistered replication in Germany and (b) an additional replication with translated stimulus materials in Sweden.
When solving mental arithmetic problems, one can easily be distracted by someone speaking in the background and this distraction is greater if the speech comprises numbers. We explored the basis of this disruption by asking participants to solve mental addition problems (e.g., "45 + 17 = ?") in three different conditions: background speech comprising numbers in ascending order (e.g., "61, 62, 63, 64, 65"), background speech comprising numbers in descending order (e.g., "65, 64, 63, 62, 61"), and quiet. Performance was best in quiet, worse in the descending numbers condition, and poorest in the ascending numbers condition. In view of these findings, we suggest that disruption arises as a by-product of preventing the primed, but inaccurate, candidate responses from assuming the control of action. Alternative explanations are also discussed.