Signal Perception in Complex Acoustic Environments: A Study on Treefrog Communication

Abstract

How animals organize complex sensory inputs to form behaviorally meaningful percepts of their environments is a fundamental question in animal behavior. For acoustically communicating animals, behavioral decisions rely on their ability to recognize signals of interest in dense social aggregations. In such environments, multiple individuals produce overlapping signals that sum to form a composite sound wave impinging on a receiver’s eardrums. Signal recognition requires a receiver to perceptually organize the composite sound wave such that the acoustic components belonging to a signal of interest are integrated into a unified perceptual representation and are also perceptually segregated from other overlapping signals. Although signal recognition has been thoroughly studied, the principles governing perceptual organization have remained relatively unexplored. Drawing parallels from studies on human perception, this dissertation aims to identify the principles of perceptual organization in non-human animals. Specifically, this work builds on the current understanding of vocal communication in treefrogs to investigate how female treefrogs recognize signals of potential mates in dense breeding aggregations. First, I examine how receivers perceptually organize simultaneous spectral components, like harmonics and formants, belonging to overlapping signals. Second, I investigate the perceptual organization of temporally repeated signal components into distinct signal sequences. Finally, I estimate how recognition of temporal patterns within signals is impacted by the presence of multiple concurrent sequences in the environment. Together, this work contributes to the understanding of perceptual mechanisms underlying signal recognition in complex acoustic environments. This work also highlights some key differences and similarities in how animals across diverse taxa perceptually organize complex acoustic inputs.