Virtuosity Unveiled: Transcending Latency

Introduction

I haven’t written anything on The Guitar Whisperer Blog in about two years. I hope this post will make the wait worthwhile. In this post, I take a look at one of the things that happens beneath the surface in high-level playing and probably can’t be inferred through observation alone. Note that I said “one of the things”; although it’s possible for visionary and expert artist-teachers to see both sides of the mountain at once, it’s difficult to show others both sides of the mountain at the same time. But leading students to a vantage point from which they can see multiple facets of the interpreter’s art simultaneously is one of the goals of superior long-term training.

Most of my professional life has been dedicated to the development of high-level skill in service to artistic expression in performance for myself and for my students. While I was a student, I noticed that many practice practices and pedagogical ideas offered by the leading guitarists and teachers of the day ended up taking students farther from the goal of artistic mastery, even if students experienced what to them were acceptable short-term results. It’s a complex subject because there are so many variables and moving parts: the availability and quality of instruction; the intrinsic or extrinsic motivation of students; the integrity of problem-recognition skills of teacher and student; the confusion of enthusiasm for discipline; the cultivation of well-informed self-criticism; and perhaps the most damaging is what I call “maestro inerrancy,” which can lead to blind acceptance of specious information. All of these deserve exploration. Underlying all of this is the conflict between the work of creating the conditions for future technical and artistic mastery and distracting oneself in pursuit of short-term results.

I’ve broached this subject in various ways before, most recently on The Guitar Whisperer Blog with my post, “Reducing Music to Technique: Intelligent Bunglers and Brainless Acrobats.” Although I didn’t use the words “The Technique-from-Pieces Fallacy” in that post, that’s what I was writing about: I gave many examples of legendary musicians describing practices that simply do not square with the way the guitar is often taught. Have a look at the post if you’ve not read it before.

Guitarists—amateurs and budding professionals—are sometimes wary of pedagogical advice that goes against the standard pedagogical party-line or what seems “intuitive” to them. I suspect that some guitar students have had bad experiences with teachers or don’t realize they could be farther along than they are. Guitar students need pedagogical specificity, yet, those who have had not-so-good experiences with teachers tend to confuse pedagogical specificity with pedagogical autocracy and chafe beneath it. The best teachers are those whose approaches are consistent with the creation of the conditions that open a path to a spacious technical and artistic future.

I don’t think this can be seen more clearly than it can be seen in the research of neurologists and psychologists who have done research on skill acquisition and motor control, even if they don’t specifically mention guitar technique in their research. Technique is skill acquisition; motor control accounts for the quality of the numerous interdependent and interlocking movements that comprise technique. It’s up to artists to make the connections between this research and the development of artistic freedom. Researchers and their studies cannot do it for us because they don’t understand how skill acquisition becomes art.

Skill Acquisition

In 1993, K. Anders Ericsson and his colleagues wrote that “research on skill acquisition indicates that performance in the initial phases of practice is determined by characteristics quite different from those that determine performance during later phases.”^[1] Ericsson uses the word “performance” in terms of executing a high-level skill, not necessarily music performance on stage, but his findings are relevant to the early training of musicians: practice during the development stage leads to “far greater changes in basic perceptual and motor abilities than previously thought.”^[2] This is especially true for activities that are comprised of numerous interdependent and interlocking high-level skills, such as found in virtuoso violin, guitar, or piano technique.

Early training should focus on securing more and better organized knowledge of one’s area of study, which includes understanding and mastering the separate components that make up a larger skill. Changes in “basic perceptual and motor abilities,” along with the acquisition of better organized knowledge, create optimal conditions for successful advanced study. As students become more advanced, they can focus on acquiring and applying the mental skills required to transcend the limits of short-term memory and to consolidate separate components of movement so they can be performed as a fluent whole and transcend the limits of what Ericsson calls “serial reaction time.”^[3]

Understanding the difference between movements that are executed serially, that is, one after another, and the consolidation of movements that are executed as part of a fluent whole, accounts for the difference between dabbling and mastery. Many of the refined movements skilled musicians make are initiated and executed within a period of time that is less than what is known as “response latency” by those who study motor control. Response latency is the interval of time between when a stimulus is perceived and a response to the stimulus begins.^[4] This latency is brief, up to 200 milliseconds, but in high-level music performance, transcending latency for difficult movements, or studying a series of movements so they coalesce into a seemingly effortless whole, is necessary for technical and artistic success. Creating the conditions for this work should be one of the goals of exceptional early training.

Motor Programs

Virtuoso violin, guitar, or piano technique—or advanced technique for any other instrument—comprises numerous high-level and interdependent skills. I don’t know how neurologists could study the development and execution of these interlocking skills. The problem becomes more daunting if one takes into account the subtle and minute variations that contribute to artistic nuance. Studies of motor control that I’ve looked at focus on how one learns a skill and what the role of feedback is in that learning or the performance of already-learned tasks that are far less complicated than those required for advanced instrumental technique.

Relatively simple skills or easy movements are the usual subjects of motor control studies. Activities such as cigar making^[5] or simple positioning tasks^[6] can be guided by sensory feedback, but actions that need to arise quickly, are of short duration, and for which there is no time to receive and act upon feedback, such as commonly occur in virtuoso instrumental performance, present challenges to those trying to form theories about motor control. In other words, the thought that initiates an action does not result in an instantaneous movement, regardless of how it appears. This won’t be seen as a problem—except to a trained ear and eye—until one attempts to reach the high speeds required to play virtuoso literature or needs to perform complex interdependent skills simultaneously.

Neurologists have observed that “complex sequences of learned movements can be executed at a rate too fast to be guided be sensory feedback, or for the individual components to each be under conscious control.”^[7] In other words, movements need to have been “preprogrammed” because “feedback loops aren’t fast enough.”^[8] Neurologists call these preprogrammed movements “motor programs.” These motor programs “permit movement sequences to be executed rapidly, as a single movement.”^[9] If one has not learned to integrate a movement that is a constituent part of a larger skill into a motor program, and the time to perceive the need for a movement and to initiate it is greater than response latency, one’s development will be constrained by the limits of serial reaction time.

Howard Austin, who received his Ph.D. from the Department of Electrical Engineering and Computer Science at the Massachusetts Institute of Technology, devoted his dissertation to an analysis of juggling. Austin’s study was meant to be read by artificial intelligence researchers and cognitive psychologists, although he also thought it would be helpful to anyone interested in motor control. Musicians who try to acquire a high level of technical skill are, in essence, involved with motor control. Austin’s study was “the first attempt to discuss a complex (as opposed to a simple) motor skill in computational terms.”^[10] In his work, Austin refers to latency as “the 200 millisecond problem.”^[11] (As a comparison, simple reflex responses—an eye blink, for example—occur in about 40 milliseconds.^[12])

If the individual movements required for a skill have not been learned, or have not learned well, as may happen if one’s first encounter with a new technique is in a piece of music, these movements will be executed serially, which will hinder technical progress and artistic expression. Unfortunately, students won’t be able to see this as the cause of any delayed progress and will either think they’re not practicing hard enough or they’re not talented. It’s usually neither: they’re not working in a way that can help them transcend the problems of latency.

There’s a relationship between perceiving and executing movements serially and the inability to solve the latency problem. (If one doesn’t think there’s a latency problem, it’s likely that one simply hasn’t experienced it because high speeds haven’t been reached or the problem has not been recognized correctly.) If one has not learned to transcend latency, movements will, perforce, be executed serially; if one has not learned to incorporate movements into a fluent whole, latency will increase.

The writings of many musicians of the past indicate that they were aware on some level of the importance of mastering the individual components of a skill before combining them. Violinist Frank Thistleton writes in 1924 in The Art of Violin Playing, “It is impossible for the beginner to concentrate on both the left and the right hand at the same time. Therefore, if the difficulties that present themselves in bowing are mastered first, we are able to give all the attention to the left hand.”^[13] In 1921, violinist Achille Rivarde (1865–1940) describes five or six different movements upon which left-hand technique is built. After describing them, he writes, “In order to gain complete mental control of these movements it is necessary to study them separately and in the simplest forms.”^[14] Howard Austin’s research shows that those who try to solve too many things simultaneously “fail to solve any.”^[15] If the individual movements that make up a high-level skill have not been worked out separately, they will not be able to be incorporated into an viable motor program and will be executed serially; if they are executed serially, one will not be able to transcend latency.

Latency varies depending on the type of stimuli: kinesthetic reaction time is about 119 milliseconds while visual latency is 190 milliseconds.^[16] The response time for auditory stimuli is about 160 milliseconds.^[17] These stimuli allow one to receive feedback and are essential while learning and practicing a skill, but trying to initiate corrections at the note level during virtuoso performance at fast tempi is impossible. Richard Schmidt of the University of Southern California writes that, “the processes involving the generation of sensory error information, perceiving it, and initiating corrections in response to those errors was quite slow, requiring from 120-200 msec.”^[18]

Motor programs are probably best understood by musicians as amalgams of interdependent “chunks” of skill that are constituent parts of a greater whole. This greater whole, in turn, becomes a larger chunk as it is assimilated into one’s technique. Although the development of these initial chunks, or micro-skills, is necessary, having developed these skills-within-a-skill is not sufficient for the development of high-level technique in service to an artistic vision. What renders their development sufficient lies in finding a way to transcend any latency connected with the initiation of a movement. But first, a digression on milliseconds.

Milliseconds by Any Other Name

Musicians work with and do things within a range of milliseconds every day. Musicians already know how much time, for example, 250 milliseconds take, even if they don’t know they do: It’s a sixteenth note played at a ♩ = 60 BPM (beats per minute). Consider the following table:

Although we don’t go about the business of practicing and making music thinking about milliseconds, milliseconds need not be unfathomable abstractions that have no meaning to us. The implications of the numbers in the above table are striking when compared to the latency times of various stimuli and point to why some ways of working are effective and others are not. If you’re playing a scale in sixteenth notes at a ♩ = 120 BPM and rely on visual feedback at the instant it’s time to make a change of position or a string cross, you’ll always be straggling because the time required for visual feedback is more than the time required for an individual sixteenth note.

When neurologists write about motor control and use the term “response latency,” they’re considering how one responds to external stimuli by initiating a movement or correcting a movement. For example, a batter at home plate needs to wait to perceive the ball thrown by the pitcher before initiating a swing of the bat. High-level solo musicians, however, don’t need to wait for external stimuli: they have learned the most efficacious time to initiate a movement, and it’s never at the instant the movement is required.

Transcending Latency

Although high-level solo musicians don’t rely upon external stimuli before initiating movements, many students and amateurs create their own external stimuli by making a cue from where they are in the piece. This cue—created by either default or intention—is often the instant a movement is needed, which will require extra time because one must first respond to the cue, that is, perceive it, before one can initiate the movement the cue is meant to trigger.

The solution to this problem is for cues to be commands to initiate something without first having to wait to respond to something. If cues are worked out in practice and occur early enough, one can initiate movements in advance and eliminate the constraints imposed by latency. “Initiate” here simply means learning when the best time is to give yourself the message to move. I can only give examples from my own discipline, concert performance of virtuoso literature on the guitar, but I hope other instrumentalists can imagine examples from their own disciplines.

A shift of position within a rapid scale, a difficult right-hand string cross, or a change of position in any fast passage, are among examples of skills that are best executed as part of a pre-programmed motor program. If guitarists follow the advice of Matteo Carcassi, Emilio Pujol, and Christopher Parkening in rapid scale playing and leave a left-hand finger on a note for its full duration, they will likely give themselves the command to shift to a new position after the note before the shift has sounded. At tempos below, say, around a ♩ = 100 BPM, this may work, although it may still result in an increase in tension. The shift, which has a technical purpose rather than an artistic purpose, will be burdened with an unwanted accent and will not be aurally transparent.^[19] (Portamenti are a different matter as they usually occur within slower tempi and taste dictates that the time for the slide should come from the previous note.^[20])

If the shift is not executed as part of a fluent whole, as is common with amateur or poorly trained players, it will be executed serially, which requires more time. This is especially true if one is preoccupied with another area of technique, e.g., right hand speed in scale playing, similar to Thistleton’s observation above. Experts develop advance cues to prepare physical movements and bypass the limits nov­ices have when it comes to executing a series of movements.^[21]

If one slavishly adheres to the standard pedagogical advice found in guitar books, one will effectively put constraints upon one’s development. Matteo Carcassi writes in his Méthode Complète from 1836 that, “A finger that is placed on a note should not be moved except to finger the following note.”^[22] This is vague, unless one is fingering successive notes with the same finger, but is usually interpreted as, “Leave your fingers on the fingerboard until it’s time to play another note.” Emilio Pujol is more specific: in his Escuela Razonada De La Guitarra, first published in 1934, he writes, “As a general principle, once a string has been stopped, the finger should not be lifted until the very end of the duration of the note in question has been reached.”^[23] Christopher Parkening writes in his guitar method, “For economy of movement and security, never lift a finger unnecessarily after it has played a note.”^[24] The important word here is “unnecessarily.” What’s necessary is tempered by one’s experience, technical level, awareness of possibilities, and artistic intent.

These books have been influential—Carcassi’s method has been reprinted and adapted many times since its initial publication—and the advice within is intended for beginners. As such, it is probably useful temporary advice so that students don’t remove their fingers from the strings prematurely, but technical “rules” often need to change as students reach higher levels of fluency. Instead, though, these directives end up being transmuted into something insidiously proscriptive: “Don’t lift left-hand fingers until the last possible instant,” is the message students absorb.

Dionisio Aguado (1784–1849) said exactly that in 1843. He writes about an arpeggio study: “The Allegro tempo makes this study more difficult than the last because the movements of the left hand must be very rapid in order to take up each new position in time after the last note of each group [by which he means ‘chord’] in the accompaniment has been clearly heard.”^[25] Aguado’s tempo marking for the piece is a ♩ = 104 BPM and the piece consists of running sixteenth notes, which means the last note of a group is 144 milliseconds long.

Aguado is, in effect, recommending that students initiate a movement at the exact time the movement is needed. The emphasis on making rapid movements at the last instant—at the expense of learning to think ahead and choreograph movements of individual fingers—is an unmerciful recipe for adding tension to one’s playing and obstructing the possibility of legato phrasing. Advice like this prevents students from learning how to transcend latency for a skill within a skill and will stunt development because students will wait to respond to something—the end of a note’s duration—before they initiate the next thing.

(See “Giuliani Revisited: Part Two” for a discussion of left-hand choreography.)

The solution to this problem is to learn to give yourself the message to shift during or prior to the note preceding the shift or harmony change. If you’re playing sixteenth notes at a ♩ = 120 BPM and anticipate the shift as you play the note immediately preceding, there are 125 milliseconds during which you can prepare mentally and facilitate the shift (or in the Aguado example, 144 milliseconds). At fast tempi, the message to move won’t even get to the hands until some portion of the note’s value has passed. With practice, one can find the most beneficial spot to think of initiating a movement—which will vary according to tempo—so it occurs with grace and fluency at the moment it’s needed. If you wait until after the note preceding the shift has sounded for its complete duration, there are no milliseconds within which to make the shift. (Note that I said “with practice.” It would be foolish to think one would work this out “on the fly” in performance.)

Inexperienced guitarists try to solve this problem by moving their left hands faster, but this results in increased tension because opposing muscles must act as a brake when the hand reaches its new position. When opposing muscle groups work against each other, however briefly, tension is created. The more tension present, the less sensitive one is to artistic nuance.

The following scale passage in measure 121 of J. S. Bach’s famous chaconne in d minor for violin illustrates this problem. I prefer to slur the first two notes of each group of thirty-second notes, except for the final one.^[26] This musical choice necessitates that all the notes in the second beat be fingered on the third string, which means one must shift from the fifth position to the second position. This shift must be mentally initiated as one strikes the c'' that occurs before the b-flat, which is the first note played in the new position:

Without this anticipatory initiation, movements will be late, rushed, and tenser than they need to be. If one has mastered the technique of shifting as a separate skill and has learned when to initiate it within a larger context, one can execute the shift seamlessly at high speed; if one follows the “keep your fingers on the string as long as possible” rule, one will most likely keep one’s mind on the note as long as possible and will not have time to make a musically sensitive shift at fast tempi. If working this way is habitual, it will cumulatively add to one’s general level of tension.

The benefits of knowing when best to initiate something is true for many other areas of technique and is probably what pianist George Kochevitsky meant when he wrote in The Art of Piano Playing: A Scientific Approach about anticipating and preparing “one’s playing apparatus for each situation without the slightest delay,”^[27] or what other teachers imply when they speak about “thinking ahead.” Of course, if one hasn’t mastered the constituent components of a complex skill, no amount thinking ahead will help.

If the components of a complex skill have not been worked out meticulously in early training, students end up relying on short-term memory and short-term skill acquisition, both of which have built-in limitations because a complex skill will exist as a series of separate processes executed in succession.^[28] The shifting example given above illustrates the importance of developing the right kind of advance cues. The development and timing of these cues allows players to perform multiple interlocking skills simultaneously. This meticulous work is one of the purposes of well-designed early training, although this purpose won’t be apparent to novices because they can’t experience its advantages until they are no longer novices.

On the guitar, I’ve noticed that there is kind of a fluency barrier beyond which many students cannot pass. The fluency barrier for scale playing on the guitar lies somewhere between sixteenth notes at a ♩ = 112–120 BPM. Although there are usually a variety of reasons for this—unnecessary tension, faulty positioning, bad technical advice—one often-imperceptible reason is that students haven’t learned to initiate movements in advance so they can transcend the problem of latency.^[29] Because this problem won’t manifest itself until high speeds are approached, progress will stall and one will not know why.

It’s not necessary for virtuosos to know that they’ve discovered ways to transcend latency or how they do it—they may think of it as “being relaxed” or “thinking ahead”—unless they’re responsible for training students. If you think you’ve stagnated at a fluency barrier, even though your overall technique is working and is free of harmful tension, consider how you’ve approached developing the skills that are embedded within larger skills, or when it is exactly that you think of initiating a movement to execute these skills.

Creating the Conditions for Mastery

The most successful early training is training that creates the conditions for mastery. One can’t teach students who need training the same way one would teach more advanced students. Exceptional early training develops the characteristics required for the initial phases of practice; characteristics necessary for advanced study grow out of this inceptive work. These conditions involve being guided through the building of a foundation of knowledge, and a foundation of physical and mental skill.

Developing virtuosity takes a long time, and it takes the right kind of work over time. Sergei Rachmaninoff wrote in 1923 that when it comes to building technique, “There are no real short cuts.”^[30] Most writing on guitar technique focuses on what one needs to do—these studies, those exercises, that piece; it’s much harder to give a sense of what happens—or needs to happen—under the hood in high-level playing. When I travel to perform concerts and give master classes, I often see students who have approached their practice by playing their pieces repeatedly with little thought to first mastering the physical and mental skills that could make their study more effective and artistically meaningful. The great violin teacher Carl Flesch (1873–1944) thought that the “habitual, thoughtless and endless repetition invariably destroys a player’s capacity for musical feeling, and at the same time robs him of that which makes the artist.”^[31] These students would be better served by following the advice of pianist Alfred Cortot (1877–1962), who insisted upon “the complete assimilation of the principle of each difficulty taken separately.”^[32]

Note:

After some discussions with my students about this post, I have made some edits and additions (November 23, 2017) to the original. Some of my students thought that their background with this and similar material facilitated their understanding, but that others might not have the larger context within which I usually explore this with individual students.