Music. Improvisation. Spontaneous creativity. How does the brain do it? In the world of improvised music, eighteen-time Grammy award-winning jazz guitarist Pat Metheny is a legend. We took a live tour of his masterful musical mind at work as he performed and engaged in discussion with leading scientists who are also all musicians—Jamshed Bharucha, whose research in cognitive psychology and neuroscience will serve to explore the biological centers of creativity; Charles Limb, an otolaryngologist, surgeon, and neuroscientist who uses fMRI to study musicians while they improvise; Gary Marcus, a developmental psychologist who taught himself to play guitar at age 40 in order to examine the process of learning music; and Aaron Berkowitz, author of The Improvising Mind: Cognition and Creativity in the Musical Moment. Through performance and conversation, the program explored the neurological processes underlying improvisation and what they tell us about human creativity and the structure of the brain.
In the middle of a World Science Festival panel on Saturday night, the guitarist Pat Metheny took a sudden U-turn from the program he had planned. Instead of performing one of his innovative compositions, plucked from any of the phases of his career as a style-shifting jazz omnivore, Mr. Metheny, performing with the bassist Larry Grenadier, decided on the spot to play a jazz standard.
And not just any jazz standard, but an especially ubiquitous one: "Autumn Leaves."
His point, during this panel called "Music and the Spark of Spontaneity," was to illustrate what some of the scientists sharing the stage had been talking about, that our brains have a kind of two-track approach to deciding what we like in the world.
On the one hand, we are wired to respond to things that are familiar, to predictability and patterns that help us make sense of what is around us. But at the same time, too much familiarity breeds, if not contempt, at least ennui or complacency. Our brains like newness too, things that surprise and deviate from an expected pattern.
"I love the idea of this question of novelty versus familiarity," Mr. Metheny said. "'Autumn Leaves,' everybody knows that." And, he added, "for the first few choruses, I'm going to use one finger on one string. I'm not going to do anything that's more complicated than anyone who could play simply would do."
Easy for him to say. Even the stripped-down version he started out with was exceptionally musical, bending the familiar melody around Mr. Grenadier's exuberantly rhythmic bass. But as their performance became more intricate and adventurous, it underscored the science: They could travel miles from the melody, they could do calisthenics with the chords, but the audience still understood it as "Autumn Leaves," something they knew spiced with something entirely different.
Our preference for combining what we expect with what surprises us was demonstrated in recent studies on what makes music expressive by Daniel J. Levitin at McGill University, and also in brain imaging research by Edward Large at Florida Atlantic University. Both scientists used classical music: Chopin piano nocturnes or etudes in which the length and volume of notes were adjusted to varying degrees. They found that musicians and nonmusicians alike responded most to versions of the Chopin that included a lot of variety but not too much, and not variety that was just thrown into the mix in a random, out-of-context way.
The World Science Festival panel in the Great Hall at Cooper Union focused mostly on improvised music, especially the intuitive art of jazz, trying to address the question of what is actually happening when a musician spontaneously creates melodies, harmonies and rhythms that have never been played before.
After "Autumn Leaves," the moderator, John Schaefer, the host of the "Soundcheck" show on WNYC, gestured to the four scientists on the panel, and said to Mr. Metheny, "Before I ask these guys what was going on in your brain, let me ask you."
Mr. Metheny gave a thoughtful recitation of the elements in a jazz musician's toolkit. "The harmony, the basic flow of the rhythms, the way the chords are divided from key to key," he said, adding that "there's a whole set of options" from which an improviser can choose, including playing different musical scales or modes over a chord – “It could be Dorian, it could be Mixolydian."
But then he Cheshire Catted it, saying, "but the real answer is I wasn't thinking about any of them." Consider that "you just asked me a question in perfect English," he said to Mr. Schaefer. "Did you think, 'O.K., I need a verb?'" or "about how to hold your tongue?"
Mr. Metheny's answer pointed up another duality in the way our brains work, that we have both conscious and unconscious brain processes, said one panelist, Jamshed Bharucha, a neuroscientist and the incoming president of Cooper Union, who is also a violinist. "The vast majority of stuff that goes on in our brain we do not have conscious access to," he said. "It's automatic."
But music requires "years and years of practice in order to make what is conscious unconscious," he said. Plus, improvisation is not just free-form playing – there has to be a mastery of structure and discipline. "If you want to fly off the edge of a cliff, you have to know where the cliff is," he said.
Improvising, in fact, may be one of the most complex abilities humans can develop because "it requires you to perfect all these different skills," said Gary Marcus, a psychology professor at New York University. Among other things, he said, improvising requires "terrific alignment between your ears and hands"; some learned or instinctive understanding of music theory; empathy, because improvising usually involves interacting with and responding to other musicians; and "fantastic motor control – you need to be both fast and accurate, and the brain's natural tendency is to be either fast or accurate."
Unraveling improvisation is, not surprisingly, a little like trying to capture a unicorn. And some people might wonder if there's a risk that scientific investigation could result in something resembling a scene in the Tom Stoppard play "Rosencrantz and Guildenstern Are Dead," in which, as more and more people are able to see a unicorn, they perceive it as something pedestrian and uninspiring: "a horse with an arrow in its forehead."
At one point, Mr. Schaefer asked, "Is it worth the effort to try and demystify something that we enjoy and that we like to think of as kind of mysterious and magical?"
Charles Limb, a surgeon and specialist in the neurology of the ear at Johns Hopkins School of Medicine, who also plays saxophone, said, "I don't think in any way that music needs science," but "music is a tool by which we can understand the brain" and the science of music "really teaches us something fundamental about who we are, why we're here."
Dr. Limb has been putting jazz musicians into a functional magnetic resonance imaging machine, a process which requires them to lie on their backs, slide into the brain scanner, and keep their heads perfectly still, while their hands, stretched out in front of them outside the scanner, play on a jury-rigged piano keyboard. The musicians' brain activity is monitored as they played a written-down jazz melody they were asked to memorize and then as they improvised to the chord changes of that melody.
When the musicians improvised, Dr. Limb found, areas of the brain's prefrontal cortex linked to self-expression were activated, but an area linked to inhibition and self-monitoring "kind of shuts down when you go creative," he said. That did not happen when musicians played a memorized piece.
Dr. Limb is also putting hip-hop artists into the brain scanner. "They're totally into it," he said. "They say, 'You know I've wanted to know what's going on in my head for the past 20 years.'" He asks them to recite a memorized rap and then to improvise lyrics using certain cued words. Preliminary results suggest that rap improvisation activates different areas from music improvisation.
Aaron Berkowitz, who has researched the neural basis of improvisation and is also a pianist and fortepianist, used a different approach to compare the brains of musicians and nonmusicians when they created five-note melodies. He found that the amount of novelty in the melodies was the same for musicians and nonmusicians, and that musicians were not activating more music-related areas of the brain. But he found that "musicians were turning off a part of the brain," involved in "a special type of attention," he said. It was a different area from what Dr. Limb was studying, but the implication is similar. The fact that this area gets inhibited when musicians play enables the performers to tune out a cellphone ring in the audience or noise from a malfunctioning amplifier, Dr. Berkowitz said.
Asked how, when performing music, he balances the ideas and feelings in his head with the external stimuli of the audience, the place he is performing, and extraneous sounds, Mr. Metheny explained his approach. He respects and appreciates the audience, but "I'm playing for myself – anything other than that would be a guess," he said. "If you start worrying about what critics say, or a record company, or the audience, then you get paralyzed. The only thing I know for sure is what I love."
Mr. Metheny said that when he plays, "to a certain degree I remain somewhat detached emotionally; I'm kind of listening" and thinking at various points, "if I was listening to this, which I am, what would I like the guitar player to play next? And I would do it, or sometimes I would do the opposite. The best musicians are not the best players, they're the best listeners."
But even Mr. Metheny's decades of experience doesn't give him the ability to always play the notes he wants to. "You've told me that actually the music coming out of the guitar is not nearly as good as what you're hearing in your head," Dr. Limb said.
"It's actually quite far away from that," Mr. Metheny said.
Dr. Marcus, who is not a musician but took up the guitar two years ago, said he realized how liberating it was to make up music and that improvising "tells us a lot about how we learn things and what we can get good at." He displayed an app he created that allows people to mix and match musical elements as a kind of half-machine, half-man method of improvising and composing.
"One of the things you start to realize is that anything starts to sound more musical when you hear it again," he said. The mixture of consistency and variability, like having a steady beat but changing the melody, he said, is why "music is as powerful as it is."
Mr. Metheny illustrated many of music's double-edged qualities Saturday night. He and Mr. Grenadier started off the program with a Metheny composition called "James," named for James Taylor because it emulates Mr. Taylor's skill at keeping a song in a single key while making it sound as if it were moving around.
"It's a tune I've played a million times, and I feel like I could play it all day long," Mr. Metheny said. "There's kind of an infinity of potential there."
And he ended the program with what was almost an inversion of that creative process, performing a scaled-down version of his orchestrion project – a one-man band that he created using intricately programmed instruments that include mallets dancing across a vibraphone, beaters striking cymbals, and an apothecary cabinet full of jugs and bottles played with blasts of air.
"I like the idea that music is something that has been invented many times," Mr. Metheny said. "Out of every population of humans, there had to have been people who just wanted to make it up, whether it was just banging on a stone and they were the baddest stone banger."
Maybe improvisation is not just the culmination of many learned abilities, but a sophisticated coordination of skills that reflects something critical about the way human brains work, the scientists and musician seemed to be saying.
"Lately," Mr. Metheny said, "I've been thinking about jazz not so much as a destination but as a process, but even more than that as a symptom."