Auditory distraction and perceptual organization: Streams of unconscious processing.

Perceptual organization is key to understanding auditory distraction. In order to achieve a fundamental understanding of distraction it is necessary to understand how auditory stimuli are perceived; specifically, how they are organized into entities that do not map directly onto simple single stimuli as defined by the experimenter. It is important not to mistake some arbitrary unit of analysis, such as the word, as the correct unit for understanding auditory processing; rather, the unit of the auditory object and its relative position to other auditory objects is the key to understanding distraction (as well as the whole of auditory cognition more generally). Here I provide two illustrative examples of auditory perceptual organization showing the superlative power of organizational principles: streaming by similarity and stimulus capture. I go on to show how these have been used to refine our understanding of distraction, and of the effects of distraction from sequences of sound, from single sounds, or single changes within a sequence. A common feature of work described here is that it compares the effects of different forms of organization: The nominal stimuli themselves are largely unchanged but the way they relate to each other can change distraction appreciably. That is, it is not the mere presence of sound that causes distraction but its organization and the way that relates to the currently prevailing activity.