Auditory grouping in the túngara frog: The roles of complex call components in what and where decisions

Abstract

Like humans, numerous animals across disparate taxa must identify and locate complex acoustic signals imbedded in multiple overlapping signals and ambient noise. A requirement of this task is the ability to group sounds into auditory streams in which sounds are perceived as emanating from the same source. Although comparatively few assays have demonstrated aspects of auditory grouping in nonhuman animals, Capranica and colleagues have revealed several excellent examples through their work with anuran bioacoustics. In this study, we build on their work by presenting evidence for auditory grouping in túngara frogs (Physalaemus pustulosus). The complex calls of P. pustulosus consist of two discrete components, which are commonly produced in multi-male choruses. By measuring the phonotactic responses of females to spatially segregated components, we show that, in contrast to humans, spatial cues play a limited role in grouping, as grouping occurs over wide angular separations. In addition, the presentation of spatially segregated call components allowed us to measure the behavioral significance of each component in the complex. We show that once grouped the separate call components are weighted differently in recognizing and locating the call, so-called ‘‘what’’ and ‘‘where’’ decisions, respectively.