New considerations for the cognitive locus of impairment in the irrelevant-sound effect.

The finding that serial recall performance for visually presented items is impaired by concurrently presented task-irrelevant speech or sounds is referred to as the irrelevant-speech/-sound effect (ISE). Substantial evidence has indicated that the impairment of serial rehearsal can result in an ISE, and this may be explained by several models. The present series of experiments has demonstrated an ISE in surprise nonserial recognition tasks in which participants were unaware of the need to maintain a large number of visual items for a later memory test, suggesting that neither the rehearsal nor maintenance of order information is necessary for observing the ISE. This effect was observed for both steady-state and changing-state irrelevant sounds, suggesting that the present results do not derive from a confusion of order information, but instead provide evidence that identity representations can also be impaired by irrelevant sound.