PEOPLE tend to move their hands when they talk. The gestural origins hypothesis posits that humans used physical gestures to communicate before they evolved the capacity for speech (Sterelny, 2012). The evidence for this is that the ability to walk on two feet (bipedalism), which freed the hands from their role in movement, preceded the expansion of the brain and skull that changed the shape of the vocal tract, facilitating speech in human evolution (Marschark & Spencer, 2011; Tattersal, 1999). It may be that the origins of syntax in language are to be found in the distinction between the hand as an agent (noun) and its movement as an action (verb) (Stokoe, 2000). In spite of the development of verbal language, humans still move their hands during speech as this enhances the quality of their communication with others. Even blind people use their hands when they talk to other people, including those they know to be blind too, although they may never have seen others gesture (Iverson & Goldin-Meadow, 1998).

Gesturing is therefore a robust phenomenon that is stable across cultures and contexts (Goldin-Meadow, 1999). The gestures that are used when they are the sole means of communication are formed in a more language-like way, however, than when they accompany speech; they have the equivalent of phonological, morphological and syntactic structure. According to McNeill, "One of the basic facts of gesture life: the gesticulations with which speech is obligatorily present are the least language-like; the signs from which speech is obligatorily absent have linguistic properties of their own" (McNeill, 2000, p. 4). This is what happens in sign-supported English (SSE). Gestures have been differentiated from signs (Kendon, 1988) on what is now termed the 'Kendon continuum' (McNeill, 1992):

spontaneous gesticulation — speech-linked gestures — emblems — pantomime — sign language

where each type of gesture varies according to a number of factors, the most salient being its relationship to speech. Spontaneous gesticulation accompanies speech. Speech-linked gestures are illustrative and can replace words, for example, 'He went [gesture]', or they can be deictic, for example, 'There [points]'. Emblems (or signs) are gestures representing consistent meanings or functions within a particular culture, such as the thumbs-up meaning 'OK', rendering speech unnecessary. Pantomime and true sign language are used, by contrast, in place of speech. Thus communication can involve the vocal and manual modalities separately and combined to different extents.

Although differing in their scope, the taxonomies of gesture produced by Ekman and Friesen (1969), Efron (1972) and McNeill (1992) contain common elements. In addition to emblems (defined above), illustrators can encompass both spontaneous gesticulation and those speech-linked gestures that are made during speech. Ekman and Friesen's original taxonomy encompassed all kinds of non-verbal cues, however, not just those conveyed by gesture: emblems can include uniforms, since they signal authority, and regulators can include eye contact, used in conversation to mediate turn-taking. Gestures are categorised, not only by type but also meaning, as deictic, iconic or metaphoric. As we have seen from the example of pointing, given above, those described as deictic assign meaning to different locations in space (Liddell, 2000) such as places, people and points in time. When a gesture imitates an action it can be described as iconic. For example, a speaker might cup his hand, the palm facing towards him, and bring it towards him, as though bending the branch of a tree, while saying 'He bends it way back' (McNeill, 2000). Metaphoric gestures present an abstract concept, known as the 'referent' of the gesture, via concrete imagery, known as the 'base' of the gesture which provides the vehicle for the metaphor (McNeill, 1992, p. 80).

GESTURE IN MUSICAL CONTEXTS

Musicians use gestures in many different ways while practising independently, rehearsing together and performing in public. Some gestures are used in the context of speech or are linked to speech but others reflect the performer's ideas about musical shape and motion. The gestures of instrumental musicians however, are rarely entirely spontaneous, as the physical demands of the musical score contribute to their repeatability over successive performances (Wanderley & Vines, 2006). Musicians develop visual mental representations of the notated score and auditory mental representations when learning, and particularly when memorising music (Chaffin, Imreh, & Crawford, 2002). These representations are also kinaesthetic involving proprioception (awareness of the body in space and around the instrument) and other, learned, physical behaviours. For example, singers have been shown to gesticulate in rehearsal, most commonly maintaining a pulse or beating time (King & Ginsborg, 2011). Such movements may have to be suppressed deliberately in performance (Ginsborg, 2009), or they may become expressive performance gestures such as those described by Davidson in her studies of Annie Lennox and Robbie Williams (Davidson, 2001, 2006). Musicians' gestures therefore often reflect rhythms, dynamics, climaxes or pauses within the music itself and, while it may come naturally to singers to gesture while singing as though they were gesturing while talking, these movements may also serve important social, communicative and expressive functions in performance.

Another form of choreographed gesture in music is the 'ballet mime' performed by the principal characters in classical ballets such as Giselle, Coppélia, Swan Lake and The Sleeping Beauty. Ballet mime uses a vocabulary of well-defined signs to convey love, anger, beauty, listening/hearing, a kiss, an order or command and even "death by crossbow and arrow" (Morina, 2000). Similarly, conductors use a repertoire of emblem-like beating patterns to indicate different temporal organisations, principally two-, three- and four beats, and it has been shown that the most salient cue for beat abstraction is the absolute acceleration along given trajectories in such beating gestures (Luck & Sloboda, 2009). The conductor's role however, extends much further than keeping time; he or she must convey expressive intentions to the ensemble so they may be communicated to the audience. Boyes Braem and Bräm (2000) examined the movements of conductors' non-dominant (i.e. non-beating) hands and identified six categories of gestures, performed using the customary handshapes illustrated in Figure 1: i) manipulating objects, including pulling out, taking out of view (such as the emblematic 'rounding-off' gesture), gathering, supporting, hitting, pushing, touching a surface and feeling a substance; ii) showing the path or form of an object, including traditional deictic movements such as pointing; iii) vertical direction such that high equates to more or louder, while low equates to less or softer; iv) portraying sound quality via the upward, 'radiating' gesture, for example; v) indicating a body part such as the chest, ears, lips and nose; and vi) holophrastic interjections including emblematic keep moving, pay attention and 'offering' gestures. Conductors' gestures can thus be simultaneously iconic, metaphoric and deictic, conveying through their location in space and direction of movement both explicit (e.g., start/stop playing now) and referential meaning (it should sound like this). They may be more or less spontaneous at different times; according to Boyes Braem and Bräm, they are influenced by musical settings and styles, audiences and the personality and culture of the conductor. They may be explicitly intentional or wholly responsive to auditory feedback: they both shape — and are shaped by — the sounds of the orchestra. Conductors physically embody (and respond to) music in the psychological present but, at the same time, consciously shape the production of music not yet sounded.

Figure 1. Handshapes used by conductors in non-dominant hand gestures, from Boyes Braem and Bräm (2000, p. 150)

GESTURE IN REHEARSAL TALK

The first author explored the effects of hearing impairment on communication during rehearsal and in the performance of music as part of a wider project investigating the potential use of vibrotactile technology to help musicians with and without hearing impairments to perform together.  1 In one study, three flautists and pianists were matched by hearing level to form three flute-piano duos, one pair with 'normal' hearing, one pair with mild or moderate hearing loss (25-69dB) and one pair with profound deafness (95 dB+). 2 The two profoundly deaf musicians, Ruth and Paul, were users of British Sign Language (BSL), having pre-lingual sensorineural deafness. Of the two moderately deaf musicians, William (flute) has an acquired sensorineural deafness caused, in part, by 40 years of professional piccolo playing in a non-acoustically treated orchestra pit. The other, Angie, was born with a moderate sensorineural deafness. Kai-Li (flute) and Manny (piano), the two hearing players, were students at the RNCM when the study was conducted in August 2011. In each session, the players rehearsed and performed two works; the slow movement of Bach's Sonata in E Major ("Adagio"), which was familiar to most players, and a work composed especially for the study to ensure both unfamiliarity and a stylistic contrast, Petite Sonate by Jacob Thompson-Bell. 3 Players were instructed to practise the pieces until they were comfortably 'under the fingers'. Each profoundly and moderately deaf player worked with their matched partner and a hearing partner (two sessions), while hearing players played with all partners (three sessions). Although two players were socially acquainted, no players had performed together prior to the study. The following research questions were posed:

1. What kinds of gestures are used when talking about music?
2. What is the effect, if any, of a hearing impairment on the production of gestures?
3. How does the production of gestures relate to the content of rehearsal talk?

In order to answer Question 3, rehearsal talk was analysed using Seddon and Biasutti's (2009) categories of Modes of Communication, shown in Table 1.

Table 1. Modes of Communication, adapted from Seddon and Biasutti (2009)

Noldus Observer XT9 was used to code gestures as Illustrators or Emblems. The latter were gestures that conveyed explicit, culturally-embedded, referential meaning and included signs borrowed from BSL. Illustrators included all other gestures and were, if possible, coded into one of three further sub-categories: gestures indicating temporal aspects of music were categorized as 'Beating'; those accompanying functional descriptions such as requests for physical cues (e.g., "You could help by moving a little bit more") were categorized as 'Demonstrators'; and gestures drawing on familiar cross-modal mappings (e.g., height to pitch, size to loudness) were categorised as 'Shaping'. All gestures were subsequently mapped to specific verbal utterances transcribed using QSR NVivo v9. Given their prevalence in musical contexts and BSL, a primary focus of the code scheme was to identify the proportion of emblematic gestures produced and to replicate the coding of Beating gestures in musical contexts in line with King & Ginsborg (2011). As prior research has suggested that gestures in music are often simultaneously iconic, metaphoric and deictic, formal classification under these categories was not attempted. Instead, the characteristics of some example tokens are discussed.

EXAMPLES and DISCUSSION

The prevalence of Illustrators over Emblems observed in the rehearsals suggests that, unlike conductors, the players did not draw upon a common repertoire of gestures (Boyes Braem & Bräm, 2000). Although fewer in number, Emblems tended to be either universal, such as thumbs-up or OK gestures, or BSL signs representing bar numbers, which is consistent with their association with Instructive speech. It is likely that the profoundly deaf musicians produced more gestures than the moderately deaf or hearing musicians because they were accustomed to communicating through BSL. The results also show that the spontaneous gesticulations of deaf musicians prompted the same behaviour in the hearing musicians, an effect that may have been caused by requests for clarification (Holler & Wilkin, 2011) or due to behavioural mirroring processes (Skipper, Goldin-Meadow, Nusbaum, & Small, 2007). While previous studies of speakers' gestures have shown that roughly a quarter occur during silent pauses (Beattie & Aboudan, 1994; Nobe, 2000), a slightly smaller proportion (19%) was found in the present study. This may be attributable to the fact that rehearsal talk differs from other kinds of talk, in that its purpose is music-making, with which it is interspersed.

The majority of Illustrative gestures (73%) could not easily be classified as Shaping, Beating or Demonstrator gestures. These general, Illustrative gestures, representing 64% of the total corpus, were polysemous in that their meaning and form depended on musical and verbal contexts. Their prevalence during Cooperative speech suggests they were best suited to supporting the communication of a variety of musical ideas including phrasing, dynamics and tempo. In contrast, Shaping gestures were produced most often during Collaborative speech, suggesting that cross-modal associations may influence the systematic formation of these gestures and, in turn, facilitate the comprehension of high-level, abstract concepts of style and interpretation. In the following sections we explore this premise by presenting examples of specific gestures relating to pulse, rubato, tempo, ensemble synchrony and 'shaping', and discuss how they represent musical meaning.

i) Pulse

The players often referred to the importance of keeping a regular beat when discussing tempo, accompanying utterances such as "It's just very, very precise" (Paul) and "But I'm just keeping my quavers going" (Ruth) with Illustrators, some of which could be classified as Beating. For example, Paul consistently used the same gesture when talking about the need to maintain a consistent, steady beat (see Figure 2 below): palms flat, facing in at chest height and 'chopping' in one or two short downward motions. In addition to the gestures analysed in the present study, Paul conducted with his left hand while playing the piano: a way of maintaining the pulse demonstrated by pianists in other research (King & Ginsborg, 2011).

Figure 2. Paul's 'chopping' gesture

Figure 3. Paul's 'breathing-block' gesture for rubato

By contrast, when Ruth asked for "A little bit more [gesture]", she gestured at the end of the phrase instead of saying explicitly what she wanted, pulling her hand gently towards her, holding an imaginary rope, then releasing it (see Figure 4). The handshape she used for this gesture is not in the standard repertoire of conductor's gestures but is used to form many different signs in BSL, in which Ruth is fluent, and can mean many different things, depending on the form and context of use.

Figure 4. Ruth's 'pull-release' gesture

Similarly, when Ruth said "You just have to listen out for a natural stretch" she made the metaphoric gesture illustrated in the left-hand panel of Figure 5 (note that it could have been described as iconic had she been referring to stretching fabric). Paul replied "But, if you do it too much, then, by the time you get to the 6^th bar it actually feels like [gesture]", making the 'pulling apart' gesture shown in the right-hand panel of Figure 5. It is revealing that the gesture began with both hands together, representing the players' synchrony; Paul clearly did not feel that pulling apart was desirable. The referents of both musicians' gestures were therefore very similar but the bases of the metaphor were conceived differently, revealing differences in both the players' conception of rubato and their opinions about its use.

Figure 5. Ruth and Paul's gestural representations of rubato as stretching and pulling apart