The above-mentioned evidence for overall consistency in interpretation poses one of the major puzzles about performance that science needs to explain. How does a performer remember the thousands of subtle performance variations that allow almost exact reproduction from performance to performance? Why isn’t the memory of the performer overwhelmed? Does the performer really need to memorize each of these individual values, as one might try to remember a very long telephone number?
Recent research shows that a great deal of performance variation can be ac-counted for by rather simple rules. The performer picks up these rules, or heuris-tics, either intuitively or by explicit instruction and then generates performances afresh each time by applying the rules. This hugely cuts down the memory load on a performer.
Although there are many individual rules, they fall into three major groups (based on the terminology suggested by Juslin, Friberg, & Bresin, 2002):
gen-erative
rules,emotional
rules, andmotional
rules. Generative rules are driven 90 Musical Skillsby the structure of the music and help to make that structure clearer to a listener.
For instance,
accenting
rules point out to a listener which elements are the most structurally important ones within a musical line. Sloboda (1983) showed that performers played the same melody differently if the metrical notation was shifted in relation to the note sequence (see the two parts of Example 5.1). per-former. From “Timing in Solo and Duet Piano Performances,” by L. H. Shaffer, 1984, Quar-terly Journal of Experimental Psychology, 36 , 577–595. Copyright © 1984. Reprinted by permission of the Experimental Psychology Society.This is one clear example of the application by performers of a generative rule.
The performers in Sloboda’s study tended to play the main beats slightly slower and louder than surrounding notes. Interestingly, performers showed no conscious awareness that the top and bottom lines of example 5.1 contained the same notes (they were separated by other, unrelated melodies in the test se-quence). Also, performers were not specifically asked to play with any expres-sion at all. They automatically changed their expresexpres-sion as a result of the vi-sual metrical information. Listeners were able to judge which of the two notations was being played just by listening to the performances, proving that these variations really did have a significant effect on the way that listeners perceived the structure of the melodies.
Another example of a generative rule relates to
grouping
of notes (e.g., phrases). Such rules help listeners to understand which elements in a piece“go together” and are separated structurally from what precedes and follows them. For instance, Repp (1992) has demonstrated that performers tend to use a typical expressive timing pattern at the ends of musical phrases. Notes at phrase boundaries are played significantly more slowly than are their neigh-bors. This means that there is a greater time gap between boundaries than anywhere else. This gap perceptually segments the music; elements on one side of the gap appear to be grouped together, in distinction from elements on the other side. Repp (1998) has also shown that these durational patterns are so “ingrained” in both performers and listeners that they tend not to be ex-plicitly noticed. He tested this by asking listeners to try to detect a small devi-ation from metronomic exactitude (a delay in the onset of a specific note) somewhere within a short musical performance. If the delay occurred at a phrase end, it was significantly harder for listeners to detect it than if it oc-curred in the middle of a phrase. The explanation for this result is that the de-lay at the end of the phrase is expected, whereas the same dede-lay in the middle of the phrase is not, and so it is more noticeable. Even the most trained lis-tener is often unable to switch off these “intelligent” mental processes that transform raw input into apprehended music. Listeners tend to hear the end 92 Musical Skills
Music example 5.1. The identical musical sequence with two alternative metrical no-tations (from Sloboda, 1983).
result (a structure) much more directly than they hear the specific means by which that structure was communicated, and so performance research cannot rely on the judgment of expert listeners alone. Rather, we need technological assistance to study performance.
Examples of
emotional
rules are provided in a study by Juslin (1997a). He asked guitarists to play a familiar melody (such as “O When the Saints Go Marching In”) in different ways to communicate different basic emotions (happy, sad, angry, and fearful). He then asked listeners to judge which emotion was present in each performance. Performers changed their performances in similar ways to communicate each specific emotion, and listeners were able to accurately judge which emotion was being conveyed. For instance, happiness is best communicated by a combination of fast speed, loudness, and a detached (staccato) articulation. Sadness is best communicated by slow speed, quiet dy-namics, and legato articulation. However, in the study not all performers were equally effective at communicating emotion. Juslin and Laukka (2000) have shown that performers can improve their emotional communication by being given feedback on their communicative effectiveness. Another finding is that some emotions are less easy to communicate than others (Juslin, 1997b). For instance, tenderness is not as well communicated or recognized as the basic emotions of happiness, sadness, fear, and anger. Finally, Juslin and Laukka (2001) have proposed that particular performance cues so readily convey emotion because they are present in speech and vocalization. A happy person speaks faster, with staccato articulation, and louder than an unhappy one. Music borrows preexisting codes from language, which may be the reason it speaks so directly to listeners. It may also be the reason that some aspects of emotional musical expression appear to “come naturally” to many performers. They are transferring an already well-known code from speech into music. They do not have to learn everything from the beginning. At the same time, musical ex-pression is not so universal as to be understandable to listeners of divergent cultures.Motional
rules are those that derive from naturally occurring movements, whether inanimate (such as the swaying of branches in the wind) or animate (such as the movement of the human body). When characteristics of these move-ments are incorporated into music performance, the expressive experience is one of naturalness or “humanness.” Performances without these motional char-acteristics may sound inhuman or “robotic.” Along these lines, Friberg and Sundberg (1987) showed that experienced classical musicians perform final slowings in a way that mirrors the deceleration of runners coming to a stop.Such slowing signals to us that the music is coming to a natural stop. Rules are specific to historical times. We intuitively sense this when listening to historical recordings (from the beginning of the twentieth century).
Expression and Interpretation 93