Analysis of Natural Scenes by Echolocation in Bats and Dolphins

Echolocation research has carefully detailed the acoustic cues used by bats and dolphins to localize and discriminate sonar targets; however, there remains an incomplete understanding of the larger problem of auditory scene analysis, namely how echo features from the natural environment are perceptually organized in the animal’s sonar receiver. This chapter reviews research that contributes to our understanding of auditory scene analysis by echolocating bats and dolphins. A review of psychophysical studies of sonar perception brings to light the limitations of understanding auditory scene analysis by echolocation when animals are constrained to a limited repertoire of emitted signals, and listening to a mix of simulated and real echoes that can compromise the perceptual salience of the experimental setting. Adaptive sonar behaviors are an integral component of echolocation systems that would be expected to feed into auditory scene analysis processes, and studies of the echolocating animal’s control over the signals it uses to probe the environment can shed light on sonar scene perception. However, adaptive sonar studies do not provide a direct measure of the animal’s perception of a complex, natural environment. Instead, auditory perception can be inferred only from the animal’s adaptive motor behaviors. Future research on auditory scene analysis by echolocation must embrace the challenge of marrying the advantages of psychophysical and adaptive motor studies, taking creative new approaches to tap into an animal’s perception of its complex, 3D auditory world, while allowing it to engage in its natural behaviors.