Proceedings of the Thirteenth International AAAI Conference on Web and Social Media (ICWSM 2019) Environmental Changes and the Dynamics of Musical Identity Samuel F. Way,1,2 Santiago Gil,2 Ian Anderson,2 Aaron Clauset1,3 1University of Colorado at Boulder, 2Spotify, 3Santa Fe Institute [email protected], [email protected], [email protected], [email protected] Abstract shapes and is shaped by musical tastes (Schwartz and Fouts 2003; Schafer¨ and Mehlhorn 2017). Studies have found re- Musical tastes reflect our unique values and experiences, our peatedly that mood regulation is among the most common relationships with others, and the places where we live. But and important reasons for why people listen to music (Slo- as each of these things changes, do our tastes also change boda and O’neill 2001; Saarikallio and Erkkila¨ 2007): music to reflect the present, or remain fixed, reflecting our past? Here, we investigate how where a person lives shapes their helps listeners relax, improve their mood, or simply relate to musical preferences, using geographic relocation to construct others through the emotions of music and its lyrics (Wells quasi-natural experiments that measure short- and long-term and Hakanen 1991). Music also plays a crucial role as effects. Analyzing comprehensive data on over 16 million a social currency, helping initiate and strengthen relation- users on Spotify, we show that relocation within the United ships (Erickson 1996), for example, through the exchange States has only a small impact on individuals’ tastes, which of new music or shared experiences at live performances. remain more similar to those of their past environments. We In these ways, music brings together individuals, forming then show that the age gap between a person and the music communities or “scenes” around particular genres, artists, they consume indicates that adolescence, and likely their en- or the lifestyles they personify (Bennett and Peterson 2004; vironment during these years, shapes their lifelong musical Lena 2012; Cohen 1991). tastes. Our results demonstrate the robustness of individuals’ musical identity, and shed new light on the development of When a community forms around some kind of mu- preferences. sic, the surrounding environment takes on an identity of its own. Cultural geographers have investigated this in- Music is the soundtrack of our lives. It reflects our mood teraction between place and musical style (Hudson 2006; and personality, as well as the important people, places, and Nash and Carney 1996), treating music as primary source times in our past (DeNora 2000). In this way, a person’s mu- material for understanding what places are or used to be sical identity—the set of musical tastes or preferences that like (Kong 1995). Research in this direction has investi- they hold, as well as anything that might modulate those gated, for example, the evolution of music styles in space preferences1 (MacDonald, Hargreaves, and Miell 2002)— and time (Carney 1974), the impact of tourism on shaping represents an ever-evolving depiction of their cumulative local musical culture (Hebdige 2003; Gibson and Connell experiences and values. Understandably then, various sci- 2003) and, the effects of migration on altering the musical entific communities have devoted much attention to resolv- landscape of places (Carney 1998; Baily and Collyer 2006). ing what determines a person’s musical tastes and, inversely, In much the same way that a person’s musical identity re- what can be inferred or predicted about someone based on flects important elements of their past and present experi- their musical tastes. Progress in either direction broadens our ences and values, the musical identity of a place tells the understanding of the development of individual identity and history of its people. culture, their rigidity and transmissibility, and the many roles These studies highlight just a few of the broader cat- that music plays in shaping our personal and social lives. egories of research on musical identity. Despite spanning A common theme in musicology research explores indi- a wide range of ideas and disciplines, a common theme viduals’ use of music to modulate or express their mood, emerges: musical identity—of individuals and places—is in- particularly among adolescents (North, Hargreaves, and herently dynamic and ever-changing. These changes happen O’Neill 2000), and the extent to which personality both both quickly, on the time-scale of our moods, and slowly, Copyright c 2019, Association for the Advancement of Artificial as the cultural landscape of our environments and music it- Intelligence (www.aaai.org). All rights reserved. self shifts gradually. However, many studies of individuals’ 1As an example, the experience of being a classically trained musical identity analyze musical taste and its correlates at a musician affects the music that person is exposed to, how they eval- single point in time. This limitation stems in large part from uate it, and, ultimately, whether or not they like it. the difficulty of characterizing people’s musical tastes, and 527 tracking their changes over time. In recent years, though, sical tastes during these periods and analytical tools to mea- more and more people listen to music online, providing a sure the impact of geographic relocation on musical tastes. detailed digital record of how individuals’ music consump- Changes in listener environment. In 2017–2018, over tion and tastes evolve over time, all over the world. 32 million Americans relocated to a new residence, with In this study, we analyze music consumption patterns approximately 4.8 million of those moves crossing state on Spotify, a popular music streaming platform2. We focus boundaries (US Census Bureau 2018). Past research has ex- specifically on the United States, the world’s largest market plored the regional subcultures of individual states, driven for music (IFPI 2018), and one of the earliest and largest in large part by historical differences in the ethnoreligious adopters of online music streaming. Coincidentally, the U.S. identities, cultural preferences, and ways of life unique to the is also one of the most studied locations in musicology re- various groups who settled the United States (Fischer 1991; search, providing rich context to guide our analyses and the Lieske 1993). In light of these regional differences, we con- interpretation of their results. We focus on understanding a sider the effects of environment on musical tastes, defining a key determinant in the development of individuals’ musi- listener’s environment as their state of residence, which we cal identity: the role of environment in shaping a person’s infer from the person’s most frequent streaming location. tastes. Specifically, we measure environments’ effects on in- Based on reports from U.S. moving companies (Allied dividuals’ preferences by treating geographic relocation as Van Lines, Inc. 2017), the majority of state-to-state reloca- the basis for constructing quasi-natural experiments, using tions happen during the summer months, when the weather a matched pairs experimental design to mitigate the effects is generally more convenient and most American education of confounding variables and natural variation. In addition, systems are on break. For this reason, we recorded state- we investigate the relationships between the age of a listener level relocations between May and September 2017. Corre- and the music they consume, informing the likely timing of spondingly, we defined a trio of three-month sample peri- when and where musical identity takes shape. ods: one just before the moving months (P1: March to May We begin by describing the primary sources of data used 2017); another immediately following the moving months in our analyses, most notably individual music consumption (P2: September to November 2017); and a third, several histories and location summaries during three sample peri- months later (P3: December 2017 to February 2018). For ods. We then outline our approach for characterizing musical each period, we aggregated users’ artist streams and stream- taste profiles, built up from data-derived music genres, and ing locations over nine randomly selected days. We then for measuring whether changes in a listener’s environment identified individuals who relocated by noting changes in induce changes in their musical tastes. We conclude with a their most frequent streaming location between periods P1 discussion of our results and an outlook on the future of mu- and P2. In later sections, we will compare individuals’ pro- sical identity research. files during these periods to assess short-term effects of re- location. Data and Methods To assess longer-term effects of relocation, we build on Our study analyzes the music consumption of Spotify users cultural norms in the United States specifying Thanksgiv- in the United States between December 2016 and February ing and Christmas as travel holidays that are tradition- 2018. After excluding individuals with low activity, miss- ally spent at home with family (Benney et al. 1959). In ing or invalid demographic information, or unreliable lo- 2017, an estimated 107 million Americans traveled in late- cation data, our dataset spans the consumption histories of December alone, with about half of those trips exceeding N=16,445,318 users, called “listeners” throughout. Con- fifty miles (American Automobile Association 2017). Our sumption histories include, for each listener: (1) daily stream sample