Expressiveness of a Marimba Player's Body Movements
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Dept. for Speech, Music and Hearing Quarterly Progress and Status Report Expressiveness of a marimba player’s body movements Dahl, S. and Friberg, A. journal: TMH-QPSR volume: 46 number: 1 year: 2004 pages: 075-086 http://www.speech.kth.se/qpsr TMH-QPSR, KTH, Vol. 46/2004 Expressiveness of a marimba player's body move- ments Sofia Dahl and Anders Friberg Abstract Musicians often make gestures and move their bodies expressing their musical in- tention. This visual information provides a separate channel of communication to the listener. In order to explore to what extent emotional intentions can be conveyed through musicians’ movements, video recordings were made of a marimba player performing the same piece with four different intentions, Happy, Sad, Angry and Fearful. Twenty subjects were asked to rate the silent video clips with respect to per- ceived emotional content and movement qualities. The video clips were presented in different viewing conditions, showing different parts of the player. The results showed that the intentions Happiness, Sadness and Anger were well communicated, while Fear was not. The identification of the intended emotion was only slightly in- fluenced by viewing condition. The movement ratings indicated that there were cues that the observers used to distinguish between intentions, similar to cues found for audio signals in music performance. Introduction envelope, and spectrum change during a tone on a violin has a direct relationship with the velocity Body movement is an important non-verbal and pressure during the bow gesture (e.g. Asken- means of communication between humans. Body felt, 1989). Also, the striking velocity in drum- movements can help observers extract informa- ming is strongly related to the height to which the tion about the course of action, or the intent of drumstick is lifted in preparation for the stroke a person. Some of this information is very ro- (Dahl, 2000, 2004). bust and can be perceived even when certain parts Musicians also move their bodies in a way of the moving body are occluded. It can even be that is not directly related to the production of perceived if the movement is shown just as single tones. Head shakes or body sway are examples points of light fastened to the body and displayed of movements that, although not having an ac- with high contrast to give a kind of discrete-points tive role in the sound generation, still can serve impression (point-light technique, see Johansson, a communicative purpose of their own. In studies 1973). It has been shown that by viewing motion of speech production, McNeill et al. (2002) have patterns, subjects are able to extract a number of argued that speech and movement gestures arise non-trivial features such as the sex of a person, from a shared semantic source. In this respect the weight of the box he/she is carrying (Rune- the movements and the spoken words are co- son and Frykholm, 1981), and landing positions expressive, not subordinate to each other. Bearing of strokes of badminton playing (Abernethy and in mind that music also is a form of communica- Russel, 1987). It is also possible to identify the tion and that speech and music have many prop- emotional expression in dance and music perfor- erties in common (Juslin and Laukka, 2003), it mances (Walk and Homan, 1984, Dittrich et al., is plausible that a similar concept applies to mu- 1996, Sörgjerd, 2000), as well as the emotional sical communication as well. In earlier studies expression in every-day arm movements such as of music performance the body gestures not di- drinking and lifting (Pollick et al., 2001, Paterson rectly involved in the production of notes have et al., 2001). been referred to as ancillary, accompanist, or Music has an intimate relationship with non-obvious movements (e.g. Wanderley, 2002). movement in several different aspects. The most We prefer to think of these performer movements obvious relation is that all sounds from traditional as a body language since, as we will see below, acoustic instruments are produced by biological they serve several important functions in music motion of humans. Some characteristics of this performance. It seems reasonable to assume that motion will inevitably be reflected in the resulting some of the expressivity in the music is reflected tones. For example, the sound level, amplitude in these movements. Speech, Music and Hearing, KTH, Stockholm, Sweden 75 TMH-QPSR Volume 46:75-86,2004 So®a Dahl and Anders Friberg: Expressiveness of a marimba player's body movements The body movements may also be used for emotional intentions Happiness, Sadness, Anger, more explicit communication. Davidson and Fear, Solemnity, Tenderness, and No expression. Correia (2002) suggest four aspects that influ- Subjects were asked to select the most appropri- ence the body language in musical performances: ate emotion for each performance. Sörgjerd found (1) Communication with co-performers, (2) indi- that subjects were better in identifying the emo- vidual interpretations of the narrative or expres- tions Happiness, Sadness, Anger and Fear than sive/emotional elements of the music, (3) the per- Tenderness and Solemnity. There were no signif- former’s own experiences and behaviors, and (4) icant differences between the presentation condi- the aim to interact with and entertain an audience. tions watch-only, listen-only or both-watch-and- To separate the influence of each of the aspects listen. In the watch-only condition, the correct suggested by Davidson and Correia on a specific emotion was more often identified for the violin- movement may not be possible, but by concen- ist than for the clarinettist. trating on solo performances without an audience, In view of the reported ability to discriminate (2) and (3) above may be the dominating aspects between different expressive intentions, an inter- and the more extra-musical influences (1) and (4) esting question to ask is what makes this discrimi- would be minimized. nation possible. What types of movements supply It is well documented that a viewer can per- the bits of information about the intent and mood ceive expressive nuances from a musician’s body of a performer? Which movement cues are used? language only. Davidson has made several studies Boone and Cunningham (2001) found that on expressive movements in musical performance children as young as 4 and 5-years old used dif- relating the overall perceived expressiveness to ferentiated movement cues when asked to move musicians’ movements (e.g. Davidson, 1993, a teddy bear to Angry, Sad, Happy and Fear- 1994, Clarke and Davidson, 1998). Most of these ful music. For the Sad music the children used studies used video recordings, utilizing the point- less force, less rotation, slower movements and light technique (Johansson, 1973) to capture the made fewer shifts in movement patterns than they movements of musicians (violinists or pianists). used for the other emotions. The children also They were instructed to play with three different used more upward movement for the Happy and expressive intentions: deadpan, projected and ex- Angry music than for Fearful (which, in turn, aggerated; instructions that were assumed to be received more upward movement than Sad mu- commonly used in music teaching. Subjects rated sic). The accuracy of children’s ability to com- these performances on a scale of expressiveness municate the emotional content to adult observers (ranging from “inexpressive” to “highly expres- was strongest for Sad and Happy music, and less sive”). From this data Davidson concluded that strong for Angry and Fearful music. subjects were about equally successful in identi- De Meijer and Boone and Cunningham pro- fying the expressive intent regardless of whether posed several movement cues considered impor- they were allowed to only listen, only watch, or tant for detecting emotional expression (De Mei- both watch and listen. Musically naive subjects jer, 1989, 1991, Boone and Cunningham, 1999, even performed better when only watching, com- see overview in Boone and Cunningham, 1998). pared to the other conditions, thus implying that These cues include frequency of upward arm many listeners at a concert may grasp the expres- movement, the amount of time the arms were kept siveness of the performance from the artist’s ges- close to the body, the amount of muscle tension, tures rather than from the musical content (David- the amount of time an individual leaned forward, son, 1995). the number of directional changes in face and Davidson also investigated which parts of a torso, and the number of tempo changes an indi- pianist’s body that conveyed the information the vidual made in a given action sequence. The pro- observers used for judging expressiveness. Using posed cues match well the findings by De Meijer, the same point-light technique as in other stud- concerning viewers’ attribution of emotion to spe- ies, presenting single or different combinations cific body movements (1989, 1991). For instance, of the points, she found that the head was im- he found that observers associated actors’ perfor- portant for the observers to discriminate between mances with Joy if the actors’ movements were deadpan, projected or expressive performances, fast, upward directed, and with arms raised. Sim- whereas the hands were not. ilarly the optimal movements for Grief were slow, Sörgjerd (2000), in her master thesis study, light, downward directed, and with arms close to found that the player’s intended emotional ex- the body. pression was reflected in the body motion and Similarly, Camurri et al. (2003) found a con- could be decoded by subjects. One clarinet nection between the intended expression of dance player and one violinist performed pieces with the and the extent to which the limbs are kept close 76 TMH-QPSR, KTH, Vol. 46/2004 to the body.