Data from: Humans recognize emotional arousal in vocalizations across all classes of terrestrial vertebrates: evidence for acoustic universals

Writing over a century ago, Darwin hypothesized that vocal expression of
emotion dates back to our earliest terrestrial ancestors. If this
hypothesis is true, we should expect to find cross-species acoustic
universals in emotional vocalizations. Studies suggest that acoustic
attributes of aroused vocalizations are shared across many mammalian
species, and that humans can use these attributes to infer emotional
content. But do these acoustic attributes extend to non-mammalian
vertebrates? In this study, we asked human participants to judge the
emotional content of vocalizations of nine vertebrate species representing
three different biological classes—Amphibia, Reptilia (non-aves and aves)
and Mammalia. We found that humans are able to identify higher levels of
arousal in vocalizations across all species. This result was consistent
across different language groups (English, German and Mandarin native
speakers), suggesting that this ability is biologically rooted in humans.
Our findings indicate that humans use multiple acoustic parameters to
infer relative arousal in vocalizations for each species, but mainly rely
on fundamental frequency and spectral centre of gravity to identify higher
arousal vocalizations across species. These results suggest that
fundamental mechanisms of vocal emotional expression are shared among
vertebrates and could represent a homologous signalling system.