REVIEW ARTICLE published: 28 February 2012 HUMAN NEUROSCIENCE doi: 10.3389/fnhum.2012.00026 Searching for roots of entrainment and joint action in early musical interactions Jessica Phillips-Silver 1* and Peter E. Keller 2,3* 1 International Laboratory for Brain, Music and Sound, Montreal, Quebec, Canada 2 Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany 3 MARCS Institute, University of Western Sydney, Australia Edited by: When people play music and dance together, they engage in forms of musical joint action Robert J. Zatorre, McGill University, that are often characterized by a shared sense of rhythmic timing and affective state (i.e., Canada temporal and affective entrainment). In order to understand the origins of musical joint Reviewed by: Robert J. Zatorre, McGill University, action, we propose a model in which entrainment is linked to dual mechanisms (motor Canada resonance and action simulation), which in turn support musical behavior (imitation and Edward W. Large, Florida Atlantic complementary joint action). To illustrate this model, we consider two generic forms of University, USA joint musical behavior: chorusing and turn-taking. We explore how these common behav- Erin Hannon, University of Nevada Las Vegas, USA iors can be founded on entrainment capacities established early in human development, *Correspondence: specifically during musical interactions between infants and their caregivers. If the roots Jessica Phillips-Silver, International of entrainment are found in early musical interactions which are practiced from childhood Laboratory for Brain, Music and into adulthood, then we propose that the rehearsal of advanced musical ensemble skills Sound, Pavillon 1430 Boulevard can be considered to be a refined, mimetic form of temporal and affective entrainment Mont-Royal, H2V 4P3, QC, Montréal, Canada. whose evolution begins in infancy. e-mail: jessica.phillips-silver@ Keywords: music, joint action, entrainment, ensemble skills, development, dance umontreal.ca; Peter E. Keller, Max Planck Research Group “Music Cognition & Action”, Max Planck Institute for Human Cognitive and Brain Sciences, 04103 Leipzig, Germany. e-mail: [email protected] INTRODUCTION movement), while the height of temporal entrainment might be What joint human behavior reveals greater coordination in time seen in the complex rhythmic timing and exchange between part- and affect – or entrainment – than music? When individuals join ners or ensemble members in music or dance (Keller et al., 2007; together in almost any musical behavior, ranging from a simple Keller, 2008; Goebl and Palmer, 2009) as portrayed by the band in tune shared between a young child and caregiver, to a rhythmi- Figure 1. cally complex performance of a Cuban Jazz band (Figure 1), their A second component of entrainment derives from the mutual joint action is characterized by entrainment. The term entrain- sharing of an affective state between individuals.Authors have even ment (from the Middle French entrainer, v., to draw, drag) is used spoken of a kind of affective “synchrony,” although we prefer the across diverse domains to refer generally to spatiotemporal coor- term entrainment in order to distinguish the temporal and affec- dination between two or more individuals, often in response to a tive components while encapsulating the essence of both. There- rhythmic signal (e.g., Phillips-Silver et al., 2010). Used in musi- fore, for the purpose of this paper we will refer to both temporal cal contexts (including dance), entrainment typically refers to the and affective entrainment. Affective entrainment involves the for- rhythmic synchronization as a product of individuals’ interaction mation of interpersonal bonds (see Feldman, 2007) and is related (Clayton et al., 2005) – that is, rhythmic coordination with simple to the pleasure in moving the body to music and being in time with (e.g., 1:1 in-phase or anti-phase) or more complex (e.g., 2:3 or 3:4 others (known in the vernacular as“groove”; Pressing, 2002; Madi- polyrhythmic) phase relations. son, 2006; Janata et al., 2012). Janata et al. (2012) have put forth One component of entrainment is thus temporal. Temporal that temporal and affective components of entrainment in music entrainment to music can be observed at hierarchical levels of met- might be inextricably linked, as for example, the quality of sensori- rical periodicity in the body (Leman and Naveda, 2010; Naveda motor synchronization (temporal) can predict the degree of expe- and Leman, 2010; Toiviainen et al., 2010) and brain (Large and rienced groove (affective), and affiliation (Hove and Risen, 2009). Jones, 1999; Large and Palmer, 2002; London, 2004; Jones, 2009; In searching for the biological roots of temporal and affective Nozaradan et al., 2011). People often experience temporal musical entrainment, early musical interactions between infants and their entrainment in the automatic, even uncontrollable head-bobbing caregivers might provide the first experiences in entrainment (e.g., or toe-tapping that occurs when we listen to musicians play (or the Malloch and Trevarthen, 2009) and thus provide a foundation for covert activation of motor areas of the brain in the absence of overt the development of skills in musical joint action (Figure 1). Frontiers in Human Neuroscience www.frontiersin.org February 2012 | Volume 6 | Article 26 | 1 Phillips-Silver and Keller Entrainment and early musical interactions FIGURE 1 | Illustrations of temporal and affective entrainment. The can be seen in early forms of joint action between an infant and skills of musical ensembles such as a Cuban Jazz band embody caretaker, and might provide a foundation for the development of temporal entrainment and musical joint action. Affective entrainment musical skills. In joint action in general, multiple individuals coordinate their entrainment mechanisms. Then in the section entitled “Ensemble movements in space and time, with a goal to communicate, or to Skills in Musical Joint Action” we consider how these mechanisms effect a change in the environment (see Sebanz et al., 2006). Here are crystallized in specific cognitive and motor skills that support we take on the term “coordination” commonly used in this liter- musical ensemble performance. We then discuss in the section ature because movements between co-actors might be coupled in entitled “The Beginnings of Musical Joint Action” some of the either a synchronized or complementary fashion, in time, or in potential ontogenetic roots for the cognitive and motor systems space. Studies of the spatiotemporal aspects of interpersonal joint required in musical joint action. In the final section, we speculate action reveal that coordination in joint action can be emergent on a possible mimetic relationship between developmental trajec- or planned (Knoblich et al., 2011). Emergent coordination occurs tories in social coordination skills and musical ensemble skills. spontaneously due to automatic processes that are grounded in perception and action couplings in the brain (Knoblich et al., COORDINATION MODES IN MUSICAL JOINT ACTION: 2011). In a non-musical example, when two conversational part- CHORUSING AND TURN-TAKING ners are engaged, they show a coordination of body sway that Chorusing and turn-taking are canonical modes of joint action is unintentional and does not require planned action (Shockley that exemplify emergent and planned coordination. Chorusing et al., 2003). Unintentional coordination of body sway can also occurs when communicative signals (sounds or movements) pro- occur between duetting musicians (Keller and Appel, 2010), an duced by separate individuals make simultaneous and roughly example that will be discussed in more detail later. The emergent equal contributions to the joint action as a whole (as in synchro- process can also be described in terms of concepts from dynam- nous chorusing observed in several species; Merker, 2000). For ical systems theory (e.g., coupled oscillators; see Schmidt and example, in multi-part music, monophonic (unison), and homo- Richardson, 2008; Oullier and Kelso, 2009; Riley et al., 2011). In phonic (chordal) textures can be considered to be instances of contrast, planned coordination requires shared representations of chorusing. In dance, the “chorus line” and the “corps de ballet” the intended outcome of the joint action and a plan for each indi- provide definitive examples of chorusing. Turn-taking involves vidual’s own role in the joint action. This can be seen in a variety of the ordering of communicative signals produced by separate indi- activities in which multiple individuals engage, including spoken viduals in such a way that there is little temporal overlap (i.e., conversation, or carrying a heavy object together (e.g., Clark, 1996, serial organization) or, when there is overlap, information in the 2005; Knoblich and Sebanz, 2008; Bekkering et al., 2009; Sebanz signal produced by only one individual has priority at any given and Knoblich, 2009). In music, both emergent (automatic head- time (hierarchical organization). Musical turn-taking occurs in bobbing) and planned (playing and dancing along) coordination antiphonal“call and response”textures (as in Afro-American blues reflect entrainment and can exert simultaneous influences on the and gospel music; Williams-Jones, 1975; Waterman, 1999) and, individuals’ actions. more generally, when instruments or dancers exchange roles, tak- How do we experience emergent and planned coordination in ing turns