Cognitive control in the cocktail party: Preparing selective attention to dichotically presented voices supports distractor suppression.

The goal of the present study was to investigate preparatory mechanisms of auditory selective attention. In two experiments, participants performed a classification task on one of two dichotically presented spoken number words, one spoken by a female, one spoken by a male. A cue indicated which gender participants had to attend to in the upcoming trial, so that attention switches and repetitions occurred randomly. The cue-target interval (CTI) was either 400 ms or 1,200 ms. Stimulus onset asynchrony (SOA) between target and distractor word varied; hence, the distractor could be presented before or after the target. In two experiments, we found robust performance costs of attention switches. Like in previous studies using versions of this paradigm, these switch costs were not significantly reduced by prolonged CTI, even though we found substantial general cue-based preparation effects. The most important finding refers to the influence of SOA, showing that the general preparation effect was greater in the condition with the distractor presented first than in the condition with the target presented first. Thus, increased time to prepare for the attention focus of the upcoming trials seems to benefit distractor suppression more than target enhancement. This occurred in switch trials and repetition trials alike, suggesting that it is a general feature of auditory attention.