Like language, the composition of music involves combining separate elements into structured and meaningful sequences. An example is the musical exercise of “trading fours.” This time-honored tradition among jazz musicians describes a pattern in which two solo musicians alternate playing four measures each, usually after each person has played a solo. Beginner musicians, especially drummers who are inexperienced in playing jazz, often find this exercise difficult. It is a skill that is only learned after much practice and determination.
Charles Limb, an associate professor at the Johns Hopkins University School of Medicine and a faculty member at the Peabody Conservatory, has united his interests in auditory science and music throughout his career. Recently, Limb has been studying jazz musicians trading fours to learn more about how the musical brain functions. He has monitored musicians’ brains using functional magnetic resonance imaging (fMRI) as they are involved in the improvisational back-and-forth musical talk. Limb’s results have provided some interesting insights on how the human brain responds to music.
Traditionally, neurological processing of auditory communication has focused on spoken language. Limb’s adaptation of these traditional methods to study musicians engaged in trading fours has allowed researchers to study communication without recourse to conventional spoken words. Limb and his colleagues have found that, despite the superficial similarity between music and language, the brain process music differently than it does spoken language.
To achieve these results, Limb’s group used highly trained jazz musicians and unique plastic keyboards lacking any metal parts that could obscure results from the highly magnetic environment of the fMRI. During the study sessions, one of the individuals involved in trading fours played his part on the specially designed plastic keyboard inside the fMRI machine.
The study’s results revealed that the posterior superior temporal gyrus and the inferior frontal gyrus, which are involved in the process of organizing words into sentences, were activated during the trading fours exchange. Surprisingly, the angular and supramarginal gyri, which are involved in neurological differentiation between word meanings or between the meanings of words or symbols, became deactivated at the same time.
In short, Limb and his group have shown that the brain processes the meaning of music and language differently. Furthermore, they demonstrated that the neurological processes associated with basic semantics may not be called upon when the brain is engaged in processing music. The brain of the musician is actively listening and processing the notes that their trading fours partner is playing in anticipation of their turn, hoping to add something new and unique to the piece.
Next time you are listening to two jazz musicians trading fours, know that they are not simply speaking to each other; they are communicating in a completely different realm.
