Musical expertise and concurrent sound segregation

Abstract

There is growing evidence suggesting that musical training can improve performance in various auditory perceptual tasks. These improvements can be paralleled by changes in scalp recorded auditory evoked potentials (AEPs). The present study examined whether musical training modulates the ability to segregate concurrent auditory objects using behavioral measures and AEPs. Expert musicians and nonmusicians were presented with complex sounds comprised of six harmonics (220, 440, 660 Hz, etc.). The third harmonic was either tuned or mistuned by 1%–16% of its original value. Mistuning a component of a harmonic complex results in the precept of a second auditory object. Stimuli were presented passively (no response) and actively (participants responded by indicating if they heard one sound or two sounds). Behaviorally both musicians and nonmusicians perceived a second auditory object at similar levels of mistuning. In both groups, complex sounds generated N1 and P2 waves at fronto-central scalp regions. The perception of concurrent auditory objects was paralleled by an increased negativity around 150 ms post-stimulus onset. This increased negativity is referred to as object-related negativity (ORN). Small differences between musicians and nonmusicians were noted in the ORN. The implication of these results will be discussed in terms of current auditory scene analysis theory.