The assessment of piano improvisation

Transcription

1 The assessment of piano improvisation HSIU-CHIN HUNG Centre for International Research in Music Education (CIRME) University of Surrey Roehampton DAVID J. HARGREAVES Centre for International Research in Music Education (CIRME) University of Surrey Roehampton

2 Abstract The purpose of this study was to investigate the consistency of 3 expert judges assessments of piano improvisations based on 4 different tasks. 12 adult improvisers with varying levels of expertise were audio recorded performing the four improvisation tasks, namely free improvisation, and three other tasks based on a melodic motif, a rhythmic motif, and thematic continuation respectively. No guidance was given with respect to musical content or style. The recordings were assessed by three independent expert judges using 5- point rating scales based on the criteria suggested by Pressing (1984), namely fluency, expressiveness, originality, playing technique, and coherence. The results show that there are significant correlations between the 5 rating scales for each piece, and for each judge. However, variations in inter-task and inter-judge correlations suggest that the judges perceived that the participants showed different qualities on different tasks. The three judges displayed varying levels of agreement on different tasks and when using different scales: their assessments corresponded more highly on the rhythmic than on the other three tasks, and corresponded less highly on the originality scale than on the other four scales.

3 Introduction The assessment of improvisation has received very little research attention in relation to the assessment of performance of written pieces, although some institutions have begun to develop certain criteria and guidelines. For example, the Associated Board of the Royal Schools of Music (ABRSM, 2002) has recently developed criteria for jazz piano assessment in which criteria of stylistic sensitivity, technical efficiency, and creativity are articulated. Rock School (2002) has also developed criteria for pop improvisation that include fluency, technical control, style acquisition, expressiveness and creativity. In Madura s (1995) study of the assessment of vocal jazz improvisation, the musical tasks and criteria were clearly articulated, and the results showed fairly high inter judge reliability. Similarly, MacPherson s (1995) Test of Ability to Improvise (TAI) showed a high level of agreement between assessments of high school instrumentalists on several tasks with precise instructions. All of these studies have worked within clear and circumscribed stylistic criteria: in many forms of jazz and pop music, for example, there exist very clear forms, conventions and exemplars which are readily identifiable by players and listeners alike. In this study, we explore the boundaries of these stylistic conventions by assessing performances on improvisation tasks in which no clear guidelines are present. The main aim of the study is to investigate whether expert judges display consistent judgments of performances on openended improvisation tasks in which there are no stylistic constraints. We pursue this aim (a) by comparing the judges assessments of performances on four different tasks, and (b) by examining the intercorrelations between five different rating scales. Research participants and procedure The study employed 12 adult improvisers, including 9 college music students at University of Surrey Roehampton, and 3 professional improvisers with experiences in contemporary/ballet/jazz/fusion. Each was invited to complete 4 improvisation tasks within 1-2 minutes on a digital piano. Written task instructions were provided to the participants before they started each task, and audio recordings were conducted. 3 independent judges assessed each of the resulting 48 improvisations using the criteria suggested by Pressing (1984): fluency, expressiveness, originality, playing technique, and coherence. Improvisation tasks In task one, the participants were invited to perform a free improvisation for about one minute. In task two, a 10 note written melody was provided and participants were asked

4 to use it as the basis for an improvisation without any specified tempo or time signature instruction. Task three was based upon a fairly complex rhythmic pattern with semi-quaver notes and syncopation. In task four, the researcher played twice a 13 notes melodic pattern twice which had a slow and calm atmosphere, and the participants were asked to continue the music. Judges The three expert judges were from different countries and musical traditions: all possess rich experiences and high levels of skill in improvising. Judge A is a female Taiwanese musician with Western classical piano training who gives concerts regularly in Taiwan, U.S.A. and Europe. She not only performs the classical music repertoire but also improvises for contemporary dance, drama and multi-arts performance. Judge B is an English musician with classical piano training background and who teaches jazz piano at several institutions in London. He regularly performs jazz in a band of his own and is a jazz composer. Judge C is a very active semi-professional jazz saxophonist as well as a lecturer in music psychology at a University in Scotland. Before making their assessments, the rationale of the study and the nature of rating scales and tasks were explained to each judge. Each judge listened individually to the audio recordings from tasks 1-4 in random order, and rated each on assessment sheets with 5 criteria: fluency, expressiveness, originality, playing technique, and coherence. Results Inter-rating scale correlations The means of the 10 inter-rating scale correlation coefficients are shown for each task and for each judge separately in Table 1 below. Table 1 Means of correlation coefficients between the rating scales for each task Judge A Judge B Judge C Task One 0.85** 0.71** 0.48 Task Two 0.82** 0.84** 0.68** Task Three 0.82** 0.67** 0.53 Task Four 0.79** 0.69** 0.76**

5 Note: ** P<0.01 All of the mean correlations are positive, and that all but two are statistically significant. Inter- task correlations The means of the 6 inter-task correlation coefficients are shown for each rating scale and for each judge separately in Table 2 below. Table 2 Means of correlation coefficients between tasks of each rating scale Judge A Judge B Judge C Fluency ** 0.66* Expressiveness 0.59* 0.61* 0.48 Originality Playing technique ** 0.59* Coherence 0.54* 0.67** 0.41 Note: ** P<.01, * P<.05 Table 2 shows that the correlations between the assessments of participants performances on the four tasks are lower for Judges A and C than for Judge B. None of the judges assessments showed significant mean correlation between the tasks on the originality scale. Inter- judge correlations on each rating scale for each task Table 3 Inter- judge correlations on each rating scale for each task Task One Task Two A-B B-C A-C Fluency Expressiveness 0.66** 0.64* 0.31 Originality ** 0.38 Playing technique 0.76** Coherence Fluency ** 0.41 Expressiveness 0.66*

6 Originality Playing technique 0.60* Coherence 0.71* Task Three Fluency 0.88** Expressiveness 0.81** 0.64* 0.57 Originality /66* 0.03 Playing technique 0.91** 0.82** 0.76** Coherence 0.89** 0.89** 0.80** Task Four Fluency * 0.47 Expressiveness Note: ** P<0.01, * P<0.05 Originality * 0.00 Playing technique ** 0.06 Coherence Table 3 shows the inter-judge correlation coefficients on each rating scale for each task. In task one, there are significant correlations between Judges A and B on expressiveness (0.66) and playing technique (0.76). Between Judges B and C, there are significant correlations on expressiveness (0.64) and originality (0.84). There are no significant correlations between Judges A and C on any of the 5 rating scales. In Task Two, there were significant correlations between Judges A and B on expressiveness (0.66), playing technique (0.60), and coherence (0.71); between Judges B and C, only fluency (0.72)showed a significant correlation. Again Judges A and C show no significant correlations on any of the 5 rating scales. In task three, stronger agreement among the judges emerged. Between Judge A and B, the results show significant positive correlations on fluency (0.88) and expressiveness (0.81). Between Judges B and C, there are significant correlations on expressiveness (0.64) and originality (0.66). Noticeably, all the 3 judges scores on playing technique (0.91, 0.82, 0.76) and coherence (0.89, 0.89, 0.80) show significant correlations. In task four, there were fewer significant correlations. The only significant correlations were on fluency (0.65) and playing technique (0.87) between Judges B and C. Table 3 shows that 21 of the 60 inter- judge correlations were not significant: it seems that the judges have quite different opinions about the consistency of the participants performances across the 4 tasks. Only in task three is there strong agreement between the judges. Task three is based on a rhythmic motif, and differs from the other 3 in that performances were generally given at a much faster tempo. The judges reached significant

7 agreement on paying technique and coherence in task three, whixh was not the case in other tasks. The possible reason might be the fast tempo of the performances in task three. The judges may have perceived the structure more easily in a fast/shorter improvisation and the demandes on technique in this task may be more obvious than the other three. Conclusion In general, the results show that although there are generally high levels of intercorrelation amongst the five rating scales adopted in this study, the levels of agreement are not as high (a) between different judges and (b) between different improvisation tasks than might be expected from tasks with more clear-cut stylistic constraints. We might make two speculations: first, that when the judges assessed each task, they may have an overall impression about the improvisation which generalised to all the 5 rating scales. Second, it may be that the different characteristics of the four tasks gave rise to different implicit assessment criteria amongst the judges, and that this resulted in lower inter-task correlations than might have been expected from more prescriptive tasks. Generally speaking, there was also a lower level of inter- judge correlation than might have been expected from more stylistically constrained tasks. The differences between the personal and musical backgrounds of the judges may have been an additional factor in this result. Dixon (2000) pointed out that assessment in the arts and humanities contains inevitable subjectivity. If the aim of assessment is to achieve a high level of reliability, this study seems to show that it might be preferable to use more circumscribed stylistic boundaries. The optimum assessment procedures, of course, depend on the aims and purpose of assessment. Assessments which are designed to gauge the degree to which a performer can work effectively within a given style, such as modern/mainstream jazz, for example, might employ scales such as those used in this study may well be effective. If the aim is to study creative improvisation without any such constraints, however, this may not be an appropriate approach. Questions about the aims and authenticity of assessment must inevitably precede those concerning its effectiveness.

8 Address for correspondence : HSIU-CHIN (CHERIE) HUNG University of Surrey Roehampton Centre for International Research in Music Education (CIRME) London SW15 5PU UK ukeastc1259@hotmail.com

9 Reference ABRSM(2002).The basis of jazz piano assessment. (accessed 26 th Feb 2002). Dixon, S. (2000). Assessing the performer, 8 th Nov Palatine workshop 26 th Feb 2002) Madura P. (1995). An exploratory investigation of the assessment of vocal jazz improvisation. Psychology of music, 23, MaPherson G. (1995). The assessment of musical performance: developmental and validation of five new measures. Psychology of music, 23, Pressing, J. (1984). Cognitive processing in improvisation, in Cognitive processes in the perception of art, eds. W. R. Crozier and A.J. Chapman.Amsterdam: Elsevier. Rockschool (2002). Assessment Criteria for Sight Reading, Improvisation & Interpretation (accessed 26th Feb 2002)