In accordance with the brilliant article by Juslin & Västfjäll (J&V) about inner human response to music, we suggest some considerations from an evolutionary perspective.
Using set theory for maximum exemplification, music, a most specialized and peculiar human cultural artifact (Andrade Reference Andrade2004; Beament Reference Beament2001), can be considered a subset of all the sounds reaching our auditory system. Principles of brain evolution (Striedter Reference Striedter2005) suggest that our brain, essentially homologous to that of primates (Klump Reference Klump, van Hemmen and Sejnowski2006), has the power of specialized modules for language and music (Geschwind Reference Geschwind1979; Liberman & Mattingly Reference Liberman and Mattingly1989; Mithen Reference Mithen2005; Peretz & Zatorre Reference Peretz and Zatorre2003; Suga Reference Suga, Greenberg and Ainsworth2006) wired and superimposed on basic mammalian (and especially primates') auditory paths (Attias & Scheiner Reference Attias, Scheiner, Jordan, Kearns and Solla1998). Psychological data confirm that the analysis of the auditory scene (biotic and abiotic sounds and species-specific sounds) is basically processed according to the same Gestalt rules that govern vision (Bregman Reference Bregman1999); and research on both music and biotic sound suggests that aversion to a sound should first involve some inherent characteristics of the sound itself (Beament Reference Beament2001; Borchgrevink Reference Borchgrevink1975; Lenti Boero & Nuti Reference Lenti Boero, Nuti, Baroni, Addessi, Roberto and Costa2006; Lenti Boero et al. Reference Lenti Boero, Nuti, Bottoni, Santiago and Bordini2007; Miraglia Reference Miraglia2007; Zentner & Kagan Reference Zentner and Kagan1996). Scherer and Zentner (Reference Scherer, Zentner, Juslin and Sloboda2001) speculate that some universal criteria of beauty are evaluated automatically on the basis of visual and auditory stimulation and arouse an affective response. Our hypothesis is that hominids' evolutionary past (Orians & Heerwagen Reference Orians, Heerwagen, Barkow, Cosmides and Tooby1992) shaped, at least in part, our sound preferences and our predisposition to respond affectively to sounds, priming aesthetic and emotional feelings toward sound appreciation or avoidance. This is analogous to how viewing a natural landscape enhances an “aesthetic” evaluation that drives settlement choices (Herzog Reference Herzog1985; Kahn Reference Kahn2001; Kaplan & Kaplan Reference Kaplan and Kaplan1989; Kaplan et al. Reference Kaplan, Kaplan and Brown1989; Tuan 1984).
Research on the evolutionary psychology of auditory scene analysis might profit from other fields, especially landscape ecology and environmental and music psychology. To our knowledge, musician William Gardiner (1771–1853) was the first to propose a relationship between natural sounds and music in his futuristic book titled The Music of Nature; or An Attempt to Prove that what is Passionate and Pleasing in the Art of Singing, Speaking, and Performing upon Musical Instruments, is Derived from the Sounds of the Animated World (Gardiner Reference Gardiner1832). Gardiner took into account tempo, rhythm, and intonation, and analyzed from a musician's perspective many naturalistic sounds such as birdsongs and mammalian utterances, transposing many of them into musical scores; many compositions from famous musicians (e.g., Mozart and Händel) were reported to have been inspired by or to imitate birdsong. One hundred and thirty years later, the Canadian composer R. Murray Schafer launched the World Soundscape Project (WSP) that inspired a seminal book The Music of the Environment (Reference Schafer1973), confirming soundscape research as an established field.
According to an evolutionary psychology hypothesis, both biotic and abiotic sounds should be emotionally appreciated in terms of the potential (positive or negative) value of the specific resource or environmental situation in which our ancestors experienced them; that is, in terms of the harm or advantage these sounds suggest (Lewis et al. Reference Lewis, Wightman, Brefczynski, Phinney, Binder and DeYoe2004). The association between the sound and the specific emitter is very important: the link is made automatically by our brain and, once acquired, might be extremely useful in conditions in which sight is limited (e.g., a deep forest), provided that some sound is produced. Current research in environmental psychology supports the idea of evolutionary primers – in fact a strong cross-cultural concordance in people's basic reaction to the sounds of natural environment has been demonstrated (McAndrew et al. Reference McAndrew, Turner, Fiedeldey and Sharma1998).
Here, we examine some results and speculate about some sound characteristics whose aesthetic and emotional value might be explained adaptively. The sound of water, fundamental for biological life, is universally appreciated, as evidenced by the many fountains in our cities and people's attraction to streams and falls (Schafer Reference Schafer1977). With regard to sound characteristics, we might consider at least the following parameters:
Periodicity versus aperiodicity. Though the advent of the Industrial Revolution produced many changes in the human acoustic environment (Schafer Reference Schafer1977), we still prefer natural soundscapes in comparison with human-influenced ones: Natural soundscapes are more valued and associated with pleasant feelings and well-being (Guillén & Lopez-Barrio Reference Guillén and Lopez-Barrio2004); they also add value to residential sites, where the sounds of a downtown street and traffic noise detract most (Anderson et al. Reference Anderson, Mulligan, Goodman and Regen1983). This possibly relates to the presence of more aperiodic sounds in an artificial soundscape. Psychophysical and neurophysiological experiments have shown that the human brain has a natural preference for harmonic and periodic sounds (Langner & Ochse Reference Langner and Ochse2006). An interesting analogy is that of instrumental classical music with its periodic sounds, which were apparently preferred by our ancestors (Beament Reference Beament2001), whereas the most threatening sounds from mammalian predators show aperiodic spectra perceived as harsh sounds, like the aperiodic spectra of thunderstorms.
Pitch. An analogous consideration might involve pitch, and the following hypothesis should be tested in the light of what is known (or still unknown) in the music emotion literature (Peretz Reference Peretz, Juslin and Sloboda2001): Low-pitched sounds emitted by large animals (or large instruments) might be associated with fear or anxiety.
Loudness. The intensity of a sound emitted by an animal gives us information about its location in respect to ours. Also, high-intensity sounds evoke higher arousal. In fact, the quality of sound's intensity from lowest to highest might be used as an expressive musical tool (e.g., as in Ravel's Bolero).
Sound variation and abundance. As with human orchestras, the most appreciated biotic soundscapes are those that include many sounds (Oba Reference Oba1994; Reference Oba1995). For modern ecologists (as for ancient hunter-gatherers), a territory with many sounds means species (and prey) abundance.
Melody variation. The history of domestication and species selection of songbirds suggests that melody variation is the characteristic most appreciated by humans; in contrast, non-singing birds (e.g., gulls) were never domesticated (Catchpole & Slater Reference Catchpole and Slater1995).
Timbre. Some mammalian utterances, such as a wolf's howls or even a dog answering a wolf's howls, convey deep emotions of anxiety and fear in people (personal observation). The same is true for other large herbivore calls (e.g., stags rutting).
These examples are not exhaustive – many others could be added, were it not for space limits. In conclusion, our contribution might be a first step in evaluating how sound (and music) emotions are at least in part shaped by selective pressures of evolution.
