TO develop a theoretical framework for empirical investigation of musical expressiveness moving beyond the question of how music represents or induces emotions—as characterized in cognitivist versus emotivist approaches to musical expressiveness (Scherer & Zentner, 2001)—this paper considers expressive forms of music as "forms of vitality." The term comes from the developmental psychologist Daniel N. Stern; it is used here to characterize musical expressiveness as fundamental to the experiencing of vitality, i.e. living (Stern, 2010), rather than musical (performance) features conceived of as correlates of specific emotions perceived or felt by listeners. According to Stern, forms of vitality, shaped dynamically, allow for the co-shaping of the (aesthetic) experience of others' expression—which can extend to an aesthetic object. Hence, this discussion is directed toward the question of how and to what extent aesthetic experience of musical expressiveness is related to the shaping and co-shaping of forms of vitality in music, and suggests hypothetical empirical studies with the potential to cope with this question.

RESEARCH ON MUSIC AND EMOTION: SOME CRITICAL DISCUSSIONS

Recently, empirical research on music and emotion has flourished, with much interest in the topic in both empirically and theoretically oriented scholarship. The topos of "music as a language of emotions," dating to the Romantic Era, has resurfaced in music research after the long 20^th-century dominance of formalist aesthetics; this renewed interest comes in conjunction with recent scientific focus on emotion, which has long been disregarded in cognition research. In psychology-centered interdisciplinary research on emotion, 1 music increasingly is used as a stimulus for empirical-experimental studies investigating the recognition or induction of emotion.

EXPRESSIVE FORMS OF MUSIC: FORMS OF VITALITY

In its attention to dynamic expressive forms of music that can be supposed as related to musicians' or listeners' experiences, 5 the concept of "forms of vitality" recently introduced by the developmental psychologist Daniel N. Stern deserves consideration. Stern claims that the experience of vitality—in the context of psychology, as related to the experience of being alive, and applied to music, dance, theater and cinema—is grounded "in physical action and traceable mental operations" and "inherent in the act of [both physical and mental] movement" (Stern, 2010, p. 9). This grounding creates a sense of time, space, force, and directionality in the human mind (Stern, 2010, p. 4). In turn, the experience of vitality serves as a basis for experiencing others' vitality, regardless of whether others' movements are observed or not.

The experience of vitality is referred to as what Stern (1985) calls "vitality affects", such as a sense of surging, fading away, sudden explosiveness, and fleetingness. Stern (2010, p. 4) contends that not only sentient beings but also time-based arts allow for the experience of vitality, and therefore move us. Five dynamic events, the "fundamental dynamic pentad," give rise to the experience of vitality: movement, force, time, space, and directionality; as a whole, these result in a "Gestalt" (Stern, 2010, pp. 4-5). For Stern (2010, p. 5), vitality is a Gestalt that "emerges from the theoretically separate experiences of movement, force, time, space, and intention". Hence, it is illogical to analyze vitality in terms of each separate element. Rather, forms of vitality are conceived of as being immediately grasped from the fundamental dynamic pentad; for instance, dynamic forms of vitality such as exploding or fading can be comprehended in terms of a graph consisting of a time axis and an intensity (force) axis. Forms of vitality are concerned with the "how" rather than the "what" of felt experiences; regardless of the content—whether emotions, thoughts or actions—that felt experiences may have, specific kinds of experience are constituted through dynamic forms of vitality. According to Stern (2010), forms of vitality are "part of episodic memories" (p. 11), and serve as "the most fundamental of all felt experience" (p. 8) when dealing with one's own movements and those of others; this takes place in the experience of time-based arts.

Interestingly, some aspects of the shaping of music related to mental experience have already been discussed in detail, by the musicologist Friedrich von Hausegger at the end of the 19^th century and the music pedagogue Alexander Truslit in the beginning of the 20^th century. Delineating the causal relation between bodily aroused states and vocalizations, Hausegger discusses dynamic forms of sound, which are experienced as an expression of mental states, in his seminal monograph "Music as Expression (Die Musik als Ausdruck)" (1887). A shaped sound depends on retaining the body's aroused state, which, rather than allowing the affected muscle to remain in consistent contraction, makes it move toward periodic activity; this influences the resulting duration, intensity, height, and depth and temporal order of vocalization (Hausegger, 1887, pp. 10-11, 62). Hausegger contends that shaped vocal sounds are not only experienced as expressions of others' aroused states, but also give rise to the "co-sense (Mitempfindung)" of arousal (p. 42). He also considers this kind of phenomenon in the context of non-sentient phenomena such as music and dance.

In the monograph "Shaping and Movement in Music (Gestaltung und Bewegung in der Musik)", Truslit (1938) tackles the coupled relationship between the shaping of music and musical experience. The shaping of music is regarded as fundamental to the musical experience, which takes place during both music-making and music perception; the latter is characterized by the listeners' "co-shaping (mitgestalten)" of music (Truslit, 1938, p. 20) through their inward experience of movement (p. 27). Basing the shaping of a sound on its duration and intensity, Truslit conceives of movement as the primordial element being shaped. Movement in music is shaped by dynamics—gradations of sound intensity changing the volume of sound as perceived—in conjunction with agogics—temporal changes of sound causing its deceleration or acceleration within the given overall temporal structure—resulting together in spatio-temporal contours of music. According to Truslit, dynamics and agogics act as fundamentals of the process of musical shaping. Truslit's "dynamo-agogics" can therefore be regarded as analogous to Stern's "forms of vitality" as applied to music.

Common to Stern, Hausegger, and Truslit, whose considerations are representatively characterized by "forms of vitality," is that 1) a shape of expression has a spatio-temporal dynamic form of movement, which consists of different elements yet is irreducible; 2) this expressive shape or its shaping is not decoupled from the experience of expression, which is understood in a broader sense than emotions; 3) that shape/shaping gives rise to its covert co-shaping by others, which leads to a co-sense of experience among the group; and 4) points 1, 2, and 3 are also valid for a non-animate phenomenon, such as music. This raises the question of to what extent the concept of "forms of vitality" can contribute to research on musical expressiveness. Crucially, this concept allows for an investigation of the way ("how") the experience of musical expressiveness is coupled with the shaping of expressive forms of music, whereas most recent studies on music and emotion have focused on the content ("what") of musical expressiveness—for instance, emotions, whether basic (Fritz et al., 2009; Juslin & Laukka, 2004) or complex (Scherer, 2004; Zentner, Grandjean, & Scherer, 2008)—and/or the mechanisms ("why") of emotions induced by music (Juslin & Västfjäll, 2008; Juslin, Västfjäll, & Lundqvist, 2010). Furthermore, expressive musical features can be considered as their holistic dynamic forms, rather than as the sum of each separable element.

Understanding "musical expressiveness" in the sense of the experience of expression—in conjunction with forms of vitality in music—shifts the focus of research on musical expressiveness to the aesthetic experience of music, a special form of musical experience not yet investigated in much detail within the scope of music and emotion research. 6 In the following section, discussion is directed toward the question of how the aesthetic experience of music can be addressed in relation to the dynamic nature of musical expressiveness being shaped and co-shaped in the course of music-making and music perception

AESTHETIC EXPERIENCE OF MUSIC

According to John Dewey, an American philosopher and psychologist, an experience becomes an aesthetic experience when: 1) "the material experienced runs its course to fulfillment" (Dewey, 1934, p. 36), reaching "an inclusive and fulfilling close" (p. 58) "through ordered and organized movement" (p. 40) deemed "dynamic" (p. 57); and 2) such experience is rounded out into "a single coherent experience" (p. 56) with a satisfying emotional quality (cf. pp. 39-40). Dewey characterizes aesthetic experience as "emotional," yet does not consider emotions separate things labeled joy, sorrow, hope, etc. (cf. p. 43); rather, he conceives of emotions as "qualities, when they are significant, of a complex experience that moves and changes" (p. 43). In Dewey's view of aesthetic experience, the dynamic quality of emotional experience again comes into play, rather than the discrete categories of the experience's content, which can merely be recognized.

Dewey (1934, p. 48 ff.) examines the shaping of the artist's experience, which he characterizes as the interplay between doing and undergoing—a simultaneous moment of both retracing what has already been done (artistically executed) and of anticipating what to do next. Hence, artistic experience, traditionally considered an artist's executive expression, is regarded as being coupled with the aesthetic experience conventionally assigned to beholders of artworks. Based on this reciprocal and cumulative relationship between doing and undergoing, an artist shapes and reshapes their production process toward fulfillment or perfection, and in this way makes the experience provided by the work of art an aesthetic experience. Such a union of doing and undergoing also underlies the perception and appreciation of a work of art. According to Dewey (1934, p. 54), this kind of receptive act "accumulating toward objective fulfillment" goes beyond passivity; he contends that, when perceiving and appreciating an artwork, the beholder (re-)creates the artist's experience of the process of dynamic organization in the work (cf. p. 56).

Taking into account Stern's and Dewey's considerations, research on musical expressiveness which directs its focus toward aesthetic experience of music requires as a starting point an aesthetic theory doing justice to the dynamic process of shaping the experience of expression, and to the process of co-shaping that accompanies music perception and appreciation. The aesthetics of empathy ("Einfühlung"), developed in the context of psychological aesthetics at the end of the 19^th century, seems appropriate to this purpose, especially in light of some recent neuroaesthetic approaches to investigating the neural mechanisms of the reciprocal relationship between doing and undergoing that are supposed to underlie the empathic aesthetic experience co-shaped while watching dance (Calvo-Merino, Glaser, Grezes, Passingham, & Haggard, 2005; Calvo-Merino, Jola, Glaser, & Haggard, 2008; Jola, Abedian-Amiri, Kuppuswamy, Pollick, & Grosbas, 2012; Jola, Davis, & Haggard, 2011) and beholding the visual arts (Di Dio & Gallese, 2009; Freedberg & Gallese, 2007; Gallese, 2010).

SUGGESTIONS FOR EMPIRICAL STUDIES ON MUSICAL EXPRESSIVENESS

Thus far this paper has established that expressive forms of music and the aesthetic experience of musical expressiveness—including the latter's underlying processes of kinaesthetic simulation—are closely related to each other; each is dynamic, characterized as unifying shaping and co-shaping as well as action and perception. This final section offers suggestions for empirical studies appropriate to the dynamic nature of musical expressiveness, which cannot be grasped in its totality by either a cognitivist or emotivist approach. Empirical research on musical expressiveness, directed toward the relationship between the (co)shaping processes of forms of vitality in music, the aesthetic experience of musical expressiveness, and its underlying simulative processes of motor reactions, should deal not only with the process of music perception, but also with that of music-making.

Developing an empirical study able to cope with the complexity of this relationship first requires discussion of methodological considerations. The simulative processes of motor reactions, assumed as underlying the aesthetic experience of musical expressiveness, can be most thoroughly investigated using neuroimaging methods to trace the neural networks involved in the music-making experienced by musicians as aesthetically expressive; the possibility of measuring neural activation over mediofrontal regions and the motor cortex is based on the results of current research on neural networks involved in empathy (Decety, 2011). Neuroimaging techniques requiring the test participant to lie in a scanner, however, are inappropriate to investigating the process of music-making: the confines of the scanner make for unnatural bodily posture and limited movement; the noise in the scanner would prevent the participant from concentrating on musical-auditory events. Electroencephalography (EEG) does not allow the musician to move their heads freely, as it is difficult to remove motor artifacts from EEG signals. Functional near-infrared spectroscopy (fNIRS) technology, as explored in a pilot study carried out by the author and colleagues using NIRScout, a portable NIRS system, imposes minimal physical constraints on the participant (when playing piano or a string instrument); nonetheless, current neuroimaging techniques require many more improvements to be reliable tools for investigating the process of music-making. On the whole, the question of what the dynamic processes of kinaesthetic simulation underlying the process of musical shaping towards fulfillment (and the co-shaping process taking place in music perception as well) look like can be most efficiently addressed by investigating the neurodynamic processes involved in music-making and music perception; such an approach does more justice to the temporal process of (co)shaping a piece of music than current structure- or function-oriented neuroscientific methods.

The issue of whether and how aesthetic experience can be made accessible by measuring the neural activity or other bodily activities leads to further methodological considerations, concerning the relationship between first-person and third-person data. As the first-person aesthetic experience is conceived of as "subjective," most experimental and empirical research at present has approached phenomenal experience from the "objective" third-person perspective. The first-person perspective has often been included into experimental design only "in a very weak sense" (Gallagher & Sørensen, 2006, p. 120)—namely, that while the participants are asked to report their experiences during the experiment, vocally or by pushing buttons, in most cases they are also instructed to focus on experimental stimuli rather than their experiences. This leaves the relationship between such experimentally induced first-person perspectives, phenomenal experience, and third-person data an open question (Northoff & Heinzel, 2006).

An examination of the relationship between first- and third-person perspectives is conceived of as only possible when based on first-person experiences; this requires the development of new first-person methodologies. Developed in France beginning in the mid-1990s within the scope of a neurophenomenological research program, neurophenomenology attempts to incorporate philosophical-phenomenological approaches into neuroscientific research (Petitmengin, Baulac, & Navarro, 2006; Petitmengin, Navarro, & Le Van Quyen, 2007; Lutz, Lachaux, Martinerie, & Varela, 2002; Varela, 1996), exploring the possibility of mutual influence between experimental participants' neural activities and the structures of their first-person experiences. A technique of phenomenological interview (Petitmengin, 2006; 2007; 2011) offers access to ostensibly subjective experience correlated with neural activations, allowing for the detection of preictal symptoms preceding epileptic seizures (Petitmengin et al., 2006). The current research on first-person experience using the techniques of the phenomenological interview aims at producing a model for the (generic) structures of experience, especially temporal structures, from interview data (Petitmengin, 2006; 2011), which can then be incorporated into analysis of the (temporal) structures of the third-person data of neural activities. Neurophenomenological approaches are well-suited for empirical study of the relationship between the aesthetic experience of musical expressiveness emerging in the process of music-making and its underlying simulative processes of motor reactions. While in-depth interview techniques collect general descriptions of musicians' experiences, including their beliefs and opinions, the phenomenological interview techniques allow for retrospection directly related to the aesthetic experience of musical expressiveness that has just taken place during the music-making; this is recalled, for instance, in terms of specific perception modalities, bodily attention and conscious images, etc. Furthermore, the process of music-making is not disrupted by a post-performance phenomenological interview. The first-person descriptions of one subject are compared to those of other subjects, attempting to find the generic (especially temporal) structures of experience, which are then related to—rather than reduced to—the (especially temporal) structures analyzed from the third-person data of neural activities. Developing a neurophenomenological study to investigate the aesthetic experience of music, however, remains highly challenging, given that temporal structures from neuroimaging data can be analyzed most efficiently when using a neurodynamic approach, whereas at present structure- and function-oriented neuroscientific approaches are dominant. The current state of phenomenological interview techniques also requires further development to investigate effectively the (generic temporal structures of) aesthetic experience of music.

The next methodological step to be considered is whether and how the forms of vitality in music being shaped in the process of music-making can be related to the structures of experience delineated by a neurophenomenological study. Up until now, musical performance features have largely been analyzed in relation to discrete emotional categories, and the dynamic expressive forms of music have rarely been related to the (co)shaping process unifying doing and undergoing. With regard to the process of music perception, several experiments call for the participants to realize this co-shaping process in an observable or measurable way, e.g. by drawing a continuous line while listening to music (Godøy, Haga, & Jensenius, 2006; Küssner, Prior, Gold, & Leech-Wilkinson, 2012; Truslit, 1938). Taking into account the thesis developed in this paper that forms of vitality in music shaped by a musician lead to their co-shaping by a listener, the listeners' co-shaping processes—in conjunction with continuous response methodology (cf. Schubert, 2010) concerning musical expressiveness as experienced by listeners during the process of a musician's music-making—can be incorporated into the investigation of the process of music-making.

A hypothesis of the empirical study on musical expressiveness to be developed beyond a cognitivist and emotivist approach might be—as in the author's 2010 case study (Kim, Demey, Moelants, & Leman, 2010)—that musical performance by professional musicians would be neither an act of mere expression of the performer's or an imagined person's emotions, nor an act of representation of emotions; rather, it would be a process of going along with music, an empathic devotion of the self to the music in shaping its production toward fulfillment or perfection, largely based on automatic processes available through embodied knowledge of the piece of music and guided by action-perception loops. To test this hypothesis, different conditions of music performance can be compared. In a case study, the author and colleagues (Kim et al., 2010) used two conditions of music performance which may have an impact on the empathic process underlying that performance: a sight-reading performance and a practised performance of a single piece not previously performed by the experimental participants. To relate the aesthetic experience of musical expressiveness to the process of shaping forms of vitality in music towards an inclusive and fulfilling close, different conditions of music performance to be compared may include a musical passage analyzed and interpreted by the musician as musically fulfilled and another, unfulfilled passage from the same piece of music.

To understand the dynamic nature of musical expressiveness, further research might be directed to-ward the role of episodic memories in the experience of musical expressiveness on the one hand and the time- and anticipation-based aspect of the perception and apprehension of musical expressiveness on the other. With regard to the latter, the musicologist and theorist Leonard B. Meyer's seminal work "Emotion and Meaning in Music" (1956) serves as a point of departure in terms of forms of vitality in music and emotional experience. A more psychologically-based approach to expectation in music perception has recently been discussed in the monograph "Sweet Anticipation: Music and the Psychology of Expectation" (2006) by the cognitive musicologist David Huron. In cognitive neuroscience of music, a recent experiment on intra-musical meaning has used hypotheses based on the expectation deriving from inner musical logic (Koelsch, 2011), following previous similar approaches to musical syntax (Koelsch, 2009; Koelsch, Fritz, Schulze, Alsop, & Schlaug, 2005; Tillmann 2005; Tillmann, Janata, & Bharucha 2003). Empirical studies appropriate to addressing the ways in which the (aesthetic) experience of musical expressiveness emerges in the process of (co)shaping forms of vitality in music can be designed by working from these theories and the results of related empirical studies.