Intelligibility of Death Metal Music 527 LISTENER EXPERTISE ENHANCES INTELLIGIBILITY OF VOCALIZATIONS IN DEATH METAL MUSIC KIRK N. OLSEN,WILLIAM FORDE THOMPSON,& (for a review, see Coffey, Mogilever, & Zatorre, 2017). IAIN GIBLIN One explanation for this enhancement is that expert Macquarie University, Sydney, Australia musicians are highly sensitive to fine-grained acoustic information that is important not only for music per- DEATH METAL MUSIC WITH VIOLENT THEMES IS ception, but also for speech perception, thereby permit- characterized by vocalizations with unnaturally low fun- ting enhanced speech intelligibility under noisy damental frequencies and high levels of distortion and conditions. However, it is not clear whether this benefit roughness. These attributes decrease the signal to noise of expertise extends to the perception of sung lyrics in ratio, rendering linguistic content difficult to under- the presence of music, a complex auditory environment stand and leaving the impression of growling, scream- in which a singer’s vocal line is embedded within mul- ing, or other non-linguistic vocalizations associated tiple instrumental textures. with aggression and fear. Here, we compared the ability For nonmusicians, evidence suggests that recognition of fans and non-fans of Death Metal to accurately of sung words is enhanced when that music is familiar perceive sung words extracted from Death Metal music. (Russo & Pichora-Fuller, 2008). However, the nature of We also examined whether music training confers an this benefit is not well understood. One possibility is additional benefit to intelligibility. In a 2 Â 2 between- that the benefit is specific to particular songs and does subjects factorial design (fans/non-fans, musicians/ not extend to unfamiliar songs from a familiar genre of nonmusicians), four groups of participants (n ¼ 16 per music. A second possibility is that familiarity with group) were presented with 24 sung words (one per a genre of music permits enhanced intelligibility of the trial), extracted from the popular American Death lyrical content for all exemplars of that genre. In that Metal band Cannibal Corpse. On each trial, participants case, recognition of sung words should be better for fans completed a four-alternative forced-choice word recog- than for non-fans of a particular genre of music, even if nition task. Intelligibility (word recognition accuracy) the specific songs in question are unfamiliar. The pres- was above chance for all groups and was significantly ent study focused on a genre of music with an extremely enhanced for fans (65.88%)relativetonon-fans ‘‘noisy’’ combination of vocal signal and background (51.04%). In the fan group, intelligibility between musi- instrumentation: Heavy Metal music and its sub-genre cians and nonmusicians was statistically similar. In the of Death Metal. We predicted that intelligibility of lyr- non-fan group, intelligibility was significantly greater ical content in Death Metal should be better for fans for musicians relative to nonmusicians. Results are dis- than for non-fans of the genre, even when the specific cussed in the context of perceptual learning and the musical pieces are unfamiliar to all listeners. benefits of expertise for decoding linguistic information An important motivation for conducting this research in sub-optimum acoustic conditions. is the violent nature of the lyrical content in a significant proportion of Death Metal music, which is considered to Received: June 11, 2017, accepted March 3, 2018. be an example of violent media. Death Metal music is Key words: auditory perception, emotion, expertise, characterized by instrumental and vocal timbres with lyrics, perceptual learning unnaturally low fundamental frequencies and high levels of distortion, roughness, and intensity that are experi- enced by listeners as loud, aggressive, and highly arous- T HAS BEEN PROPOSED THAT EXPERT MUSICIANS ing (Arnal, Flinker, Kleinschmidt, Giraud, & Poeppel, exhibit enhanced auditory skills that are under- 2015; Berger & Fales, 2005; Tsai et al., 2010; Walser, I pinned by specific changes in the brain (Kraus & 2014). Animalistic sounds normally associated with Chandrasekaran, 2010; Musacchia, Sams, Skoe, & aggression and fear, such as growls and screams, are also Kraus, 2007). These enhancements include a heightened commonplace in Death Metal vocalizations (Arnal et al., ability to comprehend speech in the presence of noise 2015; Tsai et al., 2010). Both vocal and instrumental Music Perception, VOLUME 35, ISSUE 5, PP. 527–539, ISSN 0730-7829, ELECTRONIC ISSN 1533-8312. © 2018 BY THE REGENTS OF THE UNIVERSITY OF CALIFORNIA ALL RIGHTS RESERVED. PLEASE DIRECT ALL REQUESTS FOR PERMISSION TO PHOTOCOPY OR REPRODUCE ARTICLE CONTENT THROUGH THE UNIVERSITY OF CALIFORNIA PRESS’S REPRINTS AND PERMISSIONS WEB PAGE, HTTP://WWW.UCPRESS.EDU/JOURNALS.PHP?P¼REPRINTS. DOI: https://doi.org/10.1525/MP.2018.35.5.527 528 Kirk N. Olsen, William Forde Thompson, & Iain Giblin sounds in Death Metal music have aggressive connota- which words and messages are conveyed through the tions, but the most explicit representation of violence is characteristic vocalization style. As a result, ‘‘genre- contained in lyrical content that often describe acts of specific expert listeners’’ (i.e., fans) of Death Metal music rape, murder, decapitation, and suicide. The themes may show an intelligibility advantage similar to what embedded within the lyrics are well known to fans, freely would be expected from listeners who normally exhibit available to view in online community sites, and contrib- enhanced auditory skills, such as those with many years ute to the aesthetic appreciation by fans of the genre. of formal music training (Kraus & Chandrasekaran, For example, the American Death Metal band Canni- 2010). Expert musicians show a range of enhanced audi- bal Corpse released multiple albums in the top 40 Amer- tory skills in domains outside of music, such as greater ican Billboard charts (Billboard, 2017) with titles such as intelligibility of speech in noise (Coffey et al., 2017), and ‘‘Kill’’ and ‘‘Torture,’’ and song titles such as ‘‘Relentless it’s likely that these skills will also transfer to perception Beating,’’ ‘‘Hacksaw Decapitation,’’ ‘‘Necropedophile,’’ and intelligibility of noisy Death Metal vocalizations. and ‘‘She Was Asking for It.’’ Although Death Metal is Three empirical questions were posed in this investi- a sub-genre of the more mainstream Heavy Metal genre, gation: First, to what extent can listeners understand the it still receives a relatively large worldwide following with lyrical content of Death Metal music? Second, is intel- bands such as Cannibal Corpse selling over two million ligibility of violent Death Metal vocalizations greater for albums (Blabbermouth.net, 2017). fans of Death Metal music, relative to non-fans who It is surprising, therefore, that violent Death Metal have little-to-no exposure to the distorted vocalizations music has received relatively little scientific investiga- common in Death Metal music? Third, is intelligibility tion, especially when considering the possible social and of violent Death Metal vocalizations greater for musi- psychological implications of exposure to such extreme cians with many years of music training than for indi- violent and anti-social themes. Indeed, only a small viduals with little-to-no training in music? Thus, the body of research has addressed how exposure to violent present study considers two forms of expertise: informal music might influence short- and long-term psycholog- genre-specific listening expertise and formal music ical and behavioral outcomes, or the mechanisms training. As reviewed below, existing theory and evi- underlying such outcomes (e.g., Anderson, Carnagey, dence are consistent with the hypothesis that both forms & Eubanks, 2003; Arnett, 1991; Gowensmith & Bloom, of expertise may be associated with listeners’ sensitivity 1997; Mast & McAndrew, 2011; Sharman & Dingle, to the linguistic content of Death Metal lyrics. 2015; Warburton, Roberts, & Christenson, 2014). The present study was designed to shed light on the early MECHANISMS UNDERLYING SPEECH INTELLIGIBILITY stages of this process; that is, perception and intelligi- Intelligibility is defined as the ability to accurately per- bility of violent antisocial vocalizations in Death Metal ceive and understand speech. For intelligibility to occur, music. Indeed, it is the words carried within Death the perceptual system must transform incoming acoustic Metal vocalizations—the lyrics—that are the most signals into a form that allows information in the signal direct, explicit channel with which violent themes are to interface with one’s mental lexicon. That is, the listener conveyed to listeners. must succeed in mapping sound to meaning. Linguistic Any potential consequences of violent music in soci- research has demonstrated that there are multiple levels ety are likely to apply to those who listen to that music of representation in mapping sound to meaning (Hickok on a regular basis, such as those who identify as fans. & Poeppel, 2007). For example, distinctive features are To date, research on violent music has examined its the basic inventory of sounds that characterize human impact on individuals without consideration of whether languages and are thought to be the smallest constituents they are fans of that music. Recent evidence suggests of speech that have an acoustic interpretation. Collections that fans and non-fans have very