Polyrhythms in Brain and Music

Peter Vuust & Andreas Roepstorff Listen up! Polyrhythms in Brain and Music The relationship between music and language is fiercely debated in the modern literature of neuroscience and music. Here, we argue that a musicological study of online communication between jazz musicians in combination with brain imaging studies offers a unique setting for evalu- ating communicational aspects of music practices that rarely enter the present discourse on the subject. We employ Miles Davis' quintet of the 1960s and its use of polyrhythmic structures as a general example of a jazz group focusing on communication. First, we consider jazz in the light of Roman Jakobson's model of communication in a broad perspective. Next, we analyze polyrhythmic occurrences in Herbie Hancock's solo on the jazz Standard "AU of You" as an example of how this communication develops as a narrarive structuring of tension and relief. We identify two typical types of polyrhythms, metric displacement and regrouping of subdivisions. Finally, we show how these polyrhythmic structures employ brain areas hitherto associated with linguistic semantic processing, and discuss possible implications. CORRESPONDENCE: Peter Vuust (corresponding authot). Centre of Functionally Inte- grative Neuroscience (AUH), and Royal Academy of Music, Aatfius, Denmark. EMAIL [email protected]. Andreas Roepstorff. Centre of Functionally Integrative Neuroscience (AUH), and Institute for Anthropology, University of Aartius, Aattius, Denmatk. Introduction "Music is a universal language" (Miles Davis-saxophonist George Coleman (Vuust 2000)), yet the meaning of music is of a far more abstract natura than speech (Levi-Strauss 1969). Nevertheless, musicians constantly communicate auditorially, when playing together, in order to create their musical artwork. This is indeed true in improvisational styles of music such as jazz, where possible communicational parameters include all layers in the musical structure (e.g. melody, harmony, rhythm, dynamics) (Berliner 1994, Levine 1996, Monson 1997, Sadie 2001). In jazz, as in many other musical styles, rhythm is one of the major trajectories for communication, both as a means of establish- ing and maintaining contact between musicians, and as a device for creating anticipatory patterns of tension and relief, for example between a soloist Cognitive Semiotics, Issue 3 (Fall 2008), pp. 134-158 USTENUPiPOLYRHYTHMSINBRAINANDMUSIC | 135 playing behind the beat and the rhythm section on top of the beat (Ker- schbaumer 1976). Examining die music of Miles Davis' quintet and subsequent brain experi- ments, this paper tries to evaluate some communicational aspects of music, especially with respect to the rhythmic communication that takes place in jazz. First, we shall focus on what some would call the pragmatic aspect of this music, considering it as an expression of human communication in a broad perspective. For this purpose, we show that Roman Jacobson's model of the act of communication (Figure 1) is relevant as a model for the communication between the musicians in Miles Davis' Quintet. Second, we consider the polyrhythmic' occurrences in a specific solo by Herbie Hancock as an example of how this communication may develop as a narrative structuring of tension and relief throughout the solo. In particular, we describe the characteristic usage of two different types of polyrhythm, metric displacement (MD) and regrouping of subdivisions (RS), which are known and used by most jaz2 musicians. In this specific solo, MD and RS serve dissimilar narrative and communicational purposes, which may be reflected in different communicational fimctions as described by Jakobson's model. Common to these two types of polyrhythm is that they create anticipatory structures of tension and relief, which by many musicologists are considered the main way in which music conveys meaning and emotion. Third, using modern techniques of neuroimag- ing, we shall see how engaging with these polyrhythmic structures employs brain areas hitherto mainly associated with linguistic processing. It is shown that by carefully constructing paradigms to study the different communicational functions of MD and RS, it is possible to track the neural underpinnings of these rhythmic devices. Thus, using a multi-disciplinary approach, we have the possibility of gaining insight about differential cognitive processing required to communicate through music that may not be available to us in the framework of a Single research discipline. Music and Language Similarities and differences between language and music exist on many levels and have been studied by many scientists (e.g. Brown 2001, Feld & Fox 1994, "The superposidon of different rhythms or meters". In this paper it is mainly used to describe rhythm that contradicts a given metric pulse or beat, thus synonymously with cross- rhythms. Note that by this definition, the term polyrhythm includes polymeter. 136 I P.VUUST&A.ROEPSTORFF Koelsch et al. 2004, Lerdahl 2001, Patel 2003). A central diffcrence between music and language that has been stressed by a number of writers (e.g. Besson & Schon 2001) is that music, in most cases, is of a more abstract nature than language. This relies on the fact that whereas language often refers to some extra-linguistic Space having a direct link to the physical world, music is thought to be mainly self-referential, built of objects and anticipations created within music itself: in language the signifier is distinct from the signified, whereas in music signifier 2S\A signified coincide (Padula 2006). This self-referential nature of music, however, does not necessarily mean that music cannot express concrete concepts to certain listeners in certain situations. A C-minor chord next to a C-major chord can be as concrete as a chair next to a table. This is undoubtedly true for musicians with good ears and knowledge of music theory asked to distinguish between the two chords. Another point that is often overlooked is that music, just as language, has a pragmatic aspect comprising discourse Organization and contextual influences (see e.g. Besson et al. 2001). This is in particular the case in jazz. A piece of improvisational jazz music develops as a consequence of the internal communication between the involved musicians and has its base in the immediate, personal and global history of the played piece. Düring the be-bop period of the 1940s and 1950s, the rhythmic features of jazz solos became increasingly more subde (Carr 1982). In the sixties, the fiinction of the rhythm section changed from playing a mainly supportive role to being a more Interactive parmer for the soloist (Davis & Troupe 1989). The Miles Davis Quintet from 1963-68 was a main propagator of this style of jazz in which the free communication between the musicians was the centre of the music and polyrhythm was one of the most important means (Coolman 1997). In this context, melodic phrases, rhythmic events and harmonic progressions took a form and function resembling other kinds of human communication such as those known from language. In the foUowing we shall try to demonstrate that linguistic fianctions corresponding to all of the six positions in Roman Jakobson's model of communication (Jakobson 1960) can be found in the music of Miles Davis' quintet from the 1960s. It should be noted, that even though we restrict ourselves to examples exclusively from the Davis Quintet's repertoire, communication is a constituent part of jazz, and similar analyses could be carried out for most other influential jazz groups. USTENUPIPOLYRHYIHMSINBRAINANDMUSIC | 137 Factors Functions Context Referential Sender Message Receiver Enrwtive Poetic Conative Channel Phatic Meta- Code linguistic Figure 1. Roman Jacobson's model of the act of communicationßvm "Closing Statements: Linguistics and Poettcs" (Jakobson 1960). In the act of communication then are six factors. The message (e.g. a spoken sentence) is sent from a sender to a receiver through a Channel (in a spoken sentence as sound waves through the air), in a certain code (e.g. in English), within a certdn context. Each factor corresponds to a function, mhich is encapsulated in the message: The poetic function puts the 'focus on the message for its onm sake' (Ibid: 356) and is common in messages focussing on themselves as a message, i.e. their own form, as is ofien the case forpoetty. The r^erential function is generali seen in messages referring to ohjects in the real world e.g. in newspaper stories. The conative function is common in messages that focus on Controlling the action of the receiver ("keep off the grassl"), whereas the emotive function dominates messages intended to express the emotional State of the sender, as e.g. in exclamations. The phatic function is found in words intended to open or keep the communication Channels (e.g. "hello", "hmm", "do you see, »hat I am saying?"). The meta-linguistic function dominates messages such as thesauruses, grammars etc. in which the object of the message is the language or code itself. Roman Jakobson's model of commxmication The Russian linguist Roman Jakobson su^ested a model of communication^ (Jakobson 1960) which mainly appiies to spoken conversaüon, but has proven powerfiil as a means to analyze other forms of human communicationai products, such as adverrisements and paintings (e.g. Hebert 2006). Jakobson's model (Figure 1) des to the act of communication, in which he Claims that there are 6 factors. Each of these factors corresponds to a communicative function. Ideally, all functions should be present in a message, but the message can be dominated by any one of these functions to a lesser or greater extent, as for example in the phatic message: "hello" or the conative: "the painting should not be touched". The latter demonstrates the possible multifunctionality of language. The sentence focuses on the receiver and is as 2 This model can be and has been critidzed among other things for its number of factors (Rastder 1997: 27-28; see e.g. Arcand & Bourbeau 1995: 25).

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