Commentary: Cats prefer species-appropriate music

Whether or not other animal species can appreciate human music is an issue that intrigues thinkers, scientists and artists (as well as pet owners). Yet, to date, despite a rather conspicuous corpus of studies using different investigating strategies with different animal species, no univocal answer does exist. There is contrasting evidence on the effects of music listening on animals' physiology and behavior [for a review Alworth and Buerkle (2013)] and ambiguous results on their appreciation of musical genres. To animals' ears, sometimes silence appears to be more pleasurable than human music (McDermott and Hauser, 2007; Mingle et al., 2014). At a closer look, the initial question can be reduced to a more substantial one: Why should non-human animals respond to human music? With this query in mind, Snowdon and colleagues composed ad hoc music to elicit congruent emotions in cats (Snowdon et al., 2015) and, previously, in cotton-top tamarins (Snowdon and Teie, 2010). By considering ecological and sensorial differences between species, the authors composed music starting from feats of species-specific vocalizations and animals responded to it by emitting emotionally congruent responses. Also, animals' manifestations were stronger and occurred within a shorter delay from the onset of the species-specific musical pieces than when human music was played, thus apparently proving that species-specific music is a far more relevant stimulus for them. In all musical pieces, Snowdon and colleagues included basic musical feats as modo (major or minor), articulation (legato or staccato) and structure (consonant or dissonant). These feats are universal acoustic bricks that composers regularly use to induce specific feelings in the listeners (Bresin and Friberg, 2011), and that surmount to local variations due to cultural differences (Balkwill and Thompson, 1999). Such universal acoustic bricks are also recognizable in prosody and similarly affect both human newborns of distant linguistic areas and domesticated animals (Fernald, 1992). Dogs and horses, for instance, respond congruently to verbal commands (McConnnell, 1990) as human infants do, something that has proved to be unrelated to exposure, hence conditioning. Among these universals, the consonant intervals or structures are as essential as debated. Indeed, on the specific valence of consonant sounds, the results are far from being clear. There are studies showing a preference for this type of sounds in the infants of our species (Zentner and Kagan, 1998), a baby chimp (Sugimoto et al., 2010), and newly-hatched chicks (Chiandetti and Vallortigara, 2011a). Our brain seems to be hard-wired …