The Meaning of Duplex Perception: Sounds as Transparent Objects

Abstract

In my previous research I have tried to discover how processes of auditory “scene analysis” help the listener to recognize patterns by sorting out those features of the signal that are likely to have arisen from the same source. In this work, I have often found that the scene analysis process seemed to be obeying this rule: each bit of acoustic evidence (such as a particular tone) is to be allocated to one or another perceptual stream, but not to more than one at a time (e.g., Bregman, 1978; Bregman & Rudnicky, 1975). The rule can be called “the rule of disjoint allocation”. It can be defined with reference to the familiar “vase-faces” ambiguous figure of the Gestalt psychologists. When we are aware of the faces, the line that separates a face from the vase is seen as the boundary of the face. When the vase is seen, that same line “belongs” to the vase. The same piece of sensory evidence (the line) cannot be allocated to both the face and the vase at the same time. Gestalt psychology would refer to this principle as illustrating the “belongingness” of perceived properties. One can see this belongingness principle as the natural result of the process of allocating evidence to distinct environmental objects or events.

I want to thank Bruno Repp for reading an earlier version of this paper and making many valuable suggestions. Valter Ciocca made valusble suggestions that led to Figure 3, and Pierre Abdel Ahad’s ideas contributed to Figure 2. The preparation of this paper was supported bya Research Fellowship from the Killam Foundation.