Do talker effects on auditory segregation vary with selection demands?

In naturalistic communication contexts, listeners must selectively attend to an auditory source (e.g., a person of interest) while ignoring competing auditory information. Successfully attending requires listeners both to segregate auditory objects in the scene (i.e., determine which portions of the auditory signal correspond with which sources) and to select the target stream. Previous research suggests that auditory segregation can benefit from talker differences between streams; however, it remains unclear whether this benefit might interact with demands on stream selection. In this EEG experiment, we employ a 2x2 design to examine how talker differences might interact with selection demands. Specifically, we measure memory for and electrophysiological responses to a target stream (a male voice producing ba/da/ga syllables) in the context of different kinds of distractors. To examine the influence of talker differences on auditory segregation, we manipulate whether the distractor speech is produced by the same or a different (female) talker. To test how this effect may vary with selection demands, we manipulate whether the distractor stream comprises syllables (high demands on target selection) or digits (low selection demands). Results provide insight into the perceptual and neural mechanisms that support auditory selective attention.