Enlarge /. The popular myth connects creativity to the right side of the brain, but experienced jazz musicians like Pat Metheny may rely on the left side of the brain to improvise.
Roberto Panucci / Corbis / Getty Images
There is a popular myth that divides people into "left brain" and "right brain" categories, the former being analytical and logical, while the latter are creative and innovative. Reality is of course much more complicated, and a new brain imaging study by improvised jazz guitarists is a useful example of this. Drexel University researchers found that while the right hemisphere is associated with creativity among relatively inexperienced jazz musicians, experts with a high level of improvisation skills rely primarily on the left brain. They described their results in a recent article in NeuroImage.
Co-author David Rosen is a musician and scientist who started playing the piano at the age of eight before learning bass guitar in high school. (Rosen 's band Nakama has just released a new EP for those who want to discover new musical vibrations while we are all under isolation orders.) Because improvisation – defined as "the spontaneous invention of melodic solo lines or accompaniment parts" – Rosen is a defining feature of the Jazz and thought it would be an excellent opportunity to explore the role of the brain not only for creativity but also for musical perception and expression.
"I think there are many interesting questions about (musical) perception, both for people who listen to music and for people who play music," said Rosen zu Ars. "The brain is the part that makes us the most human and makes us feel these emotions. It’s almost impossible to quantify the state of change we get into when we play or listen to the music that we like the most, and that means the most we as individuals. Ultimately we try to ask very focused scientific questions about what it means to be part of this musical experience. "
In the zone
Jazz musicians often talk about moments during live performances in which all band members are "in the zone", so to speak, reacting and reacting to each other instead of concentrating more internally on their own independent creative decisions. For Rosen, this is the essence of improvisation.
"The mastery of jazz depends very much on the ability to improvise with different musicians in different scenarios," said Rosen. "And improvising in jazz is really difficult because there are so many different chords. Chord sequences can be quite complex, with changes happening very quickly." From a neuroscientific point of view, this is a task that puts a heavy cognitive strain on the brain, but master jazz musicians can perform this demanding task in real time thanks to years of rigorous training.
Enlarge /. A jazz guitarist improvises while his brain activity (EEG) is being recorded.
How exactly do you measure a nebulous concept like "creativity" with a certain degree of robustness? Rosen et al. used an established method for their study, known as the "consensus assessment technique", in which experts check material – whether music, film, etc. – on different scales. In this case, a jury of four experienced musicians and teachers assessed how creative the improvisations of the subjects were, how aesthetic the performances were and what technical skills the subjects had.
All three measurements were collected independently and proved to be strongly correlated, which gave the team a measurable quality factor for the experiment. The experts rated their "interrater reliability" on all three scales very high. "So we have signs that these people are consistent in their actions," said Rosen. "Without this reliability, we would just say:" OK, rate the opinions of random people. "
Thirty-two jazz guitarists – some very experienced, some relative beginners – took part in the study. Each topic was asked to improvise on six jazz lead sheets while connected to an EEG machine. Their playing was accompanied by programmed drums, bass and piano. The resulting 192 recordings were then played back to the panel of experts, who assessed them for creativity and other related properties. Then Rosen et al. compared the highest and lowest scores to the recorded EEGs to determine which areas of the brain showed more activity.
The first results showed that there was more activity on the left side of the brain for high-rated performances on the creativity scale, and higher activity in the right hemisphere for activities with lower ratings. According to Rosen, this statement makes sense if one considers the level of experience of a musician.
While the right brain is associated with things like conscious control and motor planning, the left brain is generally more busy with routine or routine tasks. "If you do something over and over again, you will be really good at this task," said Rosen. "But that may not necessarily tell us when the expert has a novel or creative experience while doing the job. In our behavioral models, we found that expertise contributes to a significant variance in predicting the results of improvisation assessments."
SPM topographic significance cards from the jazz improvisation study
D.S. Rosen et al./Drexel University
Brain activity maps show areas associated with high creativity achievements versus low creativity accomplishments. Each card shows a top view of the head
If expertise was the main reason for the observed effect, the team would hardly have had to find any differences in brain scan data when statistically checking the expertise (particularly in terms of public performance). Instead, there were significant differences in brain activity in the right hemisphere (especially in the frontal region) between performances that were rated high and services that received lower creativity ratings.
In short, experts were rated highest by the jury, although they approached the task of improvising jazz with the most routine routines. Rosen partly attributes this to the fact that a beginner, for example, has to go through 16 bars of music on a lead sheet every quarter, while an expert can find patterns like a two-five-one progression. "This allows them to approach the test with a reduced level of cognitive control," he said. Creativity is associated with the right hemisphere when we are dealing with an unusual situation and with the left hemisphere when we are very experienced with the task at hand.
"When defining creativity in terms of the quality of a product such as a song, an invention, a poem, or a painting, the left hemisphere plays a key role," said Rosens co-author John Kounios, director of Drexels Applied and Cognitive Brain Science Program. "However, when creativity is understood as a person's ability to deal with new, unknown situations, as is the case with inexperienced improvisers, the right hemisphere plays the leading role."
A double process
This experiment will feed into a growing body of research at Rose's new music technology startup, Secret Chord Laboratories, which develops software to predict listener response to a particular piece of music. The company is currently targeting the recording industry, which is always looking for the next hit single. (Rosen describes his mission as "interdisciplinary research into the neurosciences of music".)
The core technology came from an earlier study Rosen conducted with Georgetown University's Scott Miles on music perception to investigate what sound patterns, if any, cause a pleasure reaction in the brain. They've watched Hot 100 songs on the Billboard charts, from "Johnny B. Goode" in 1958 to Nirvana's "Smells Like Teen Spirit" in 1991. "We analyzed each chord of each of these songs and a statistical one Tested to see if the top quartile charts had a different level of the harmonic structure we called the "familiar surprise", "said Rosen.
They found that the most popular songs had a high level of harmonic surprise, defined as points at which the music deviated from the expectations of the listener – for example, the use of relatively rare chords in verse instead of just sticking to the standard C. hold. Main chord progression (C, G, F). The best songs follow this harmonic surprise with a catchy common refrain. The resulting patents – since then expanded to include rhythm, melody, timbre and texts as well as harmonies – led to the foundation of the company.
Rosen and his colleagues next plan to analyze the data of the jazz guitarist in order to examine the neuronal correlates of so-called "flow states". He also believes that it may be possible to design an experiment to test his hypothesis that jazz musicians do some form of "switching" and amass various tricks and techniques that they can use if they become temporarily baffled during an improvisation performance . "Once we have people back in the labs, we can really throw in strange chords or listen to music that doesn't match the lead sheet to see how quickly they respond to the drop," he said.
"My hypothesis is that (experts) can return to the brain state they were in earlier than a beginner could," said Rosen. "The double process is not just that beginners use all control and executive functions and that experts don't use any. It is about the interaction of these systems and those that prevail in the different levels of competence."
DOI: NeuroImage, 2020.10.1016 / j.neuroimage.2020.116632 (About DOIs).