Informational Masking Can Constrain Acoustically Guided Mating Behavior

Abstract

AbstractNoisy social environments constrain human speech intelligibility in two primary ways: spectro-temporal overlap between signals and noise reduces speech audibility (“energetic masking”) and noise interferes with processing the informative features of otherwise audible speech (“informational masking”). To date, informational masking has not been investigated in studies of vocal communication in nonhuman animals, even though their behavioral decisions frequently depend on extracting information from vocalizations in noisy aggregations. In this study of a treefrog, in which females chose mates in noisy breeding choruses, we investigated whether informational masking can disrupt the processing of signal information in the contexts of species recognition and sexual selection. We observed significant reductions in response to the vocalizations of a potential mate when they were broadcast concurrently with other biologically relevant sounds designed to reduce or eliminate energetic masking. These effects were more pronounced when competing sounds were present in a particularly salient frequency range for processing vocalizations. Among responsive subjects, however, performance in signal recognition and discrimination tasks remained largely unchanged. These results confirm that informational masking is a general communication problem among humans and other animals and suggest it may be a crucial yet understudied source of selection shaping the evolution of animal communication.