Contribution
Which role does harmonic clarity play in the preference of harmonic sounds across species?
* Presenting author
Abstract:
Music is a unique communication system rooted in human biology. Its evolution can be studied by comparing abilities that are shared between species and possibly shaped by similar selective pressures. Human vocalizations and music feature clear harmonics (integer multiples of the sounds fundamental frequency, unobscured by noise) that help voices to merge while singing together, which fosters adaptive social bonding and may render clear harmonics attractive to humans. Following this reasoning, known as vocal similarity hypothesis, we hypothesized that, conversely, species with noisy vocalizations would prefer noisy sounds. Budgerigars (Melopsittacus undulatus), a parrot species that shares analog traits important for music (e.g., vocal learning and coordination) mainly produce noise-obscured harmonics. We conducted place preference experiments to assess which sounds budgerigars and humans preferred to spend time with. Budgerigars overall showed no preference for either clear or noisy sounds, while humans preferred clear sounds. This suggests that sound preferences may be driven by additional factors, such as arousal cues, shared across species. Understanding how different species use the harmonic frequency spectrum, considering traits like vocal learning, can help us to better understand the biological bases of sound preferences and further clarify possible evolutionary functions of music.