Informational Masking Constrains Vocal Communication in Nonhuman Animals

Animals often communicate acoustically in noisy social environments, yet how receivers extract relevant information from overlapping sounds is poorly understood. Studies of animal communication in noise are typically based on a traditional filterbank model of hearing focused on energetic masking, where spectrotemporal overlap in peripheral auditory filters limits signal audibility. By contrast, studies of human speech show that background sounds can also interfere with selecting and attending to otherwise audible signals in a phenomenon known as informational masking. Whether informational masking constrains acoustic communication in nonhuman animals remains poorly understood. Through controlled laboratory experiments with treefrogs (Hyla chrysoscelis), we demonstrate, for the first time in a nonhuman animal, that informational masking can impair crucial mate-choice decisions when vocal signals and other concurrent sounds share similar temporal features. These impacts spanned a wide range of signal-to-noise ratios, occurred in the absence of spectrotemporal overlap in the auditory periphery, and were strongest when interfering sounds fell within a frequency band salient for vocal processing. Our findings challenge conventional views on how noise impacts animal communication by establishing informational masking as a general communication problem shared by humans and other animals. These results highlight the need to distinguish between energetic and informational masking to understand the evolution of signaling in complex acoustic environments.