Humans correctly assign emotional valence of rat vocalizations

Emotions are signalled among conspecifics but also to other species to facilitate ethologically meaningful responses towards external and internal cues. An unresolved question, however, is whether the universality of emotional recognition extends to vocalizations that lie outside a species' natural auditory range. Here we asked whether humans perceive emotional content of frequency-shifted rat ultrasonic vocalizations. We found that human subjects correctly assigned emotional valence to the artificially transposed vocalizations, with certain dependencies on the degree of the frequency shift. This suggest that vocal emotional communication is highly conserved across species and that continuous sensory exposure is unlikely to be required for evolutionary preservation of these vocal expressions.