by Daniel Josh Quillen
The study took ten people who regularly received “chills to instrumental music” and ran an fMRI combined with a ligand-based Positron Emission tomography (PET) scan while they listened to music. The results showed not surprisingly that music causes a release of dopamine in the dorsal and ventral striatum which have long been correlated in all pleasurable experiences from sex to recreational drug use to food consumption. What was interesting was the timing of certain responses. Prior to the climax of the music there was an increase in activity in the caudate nucleus. They argue that this is the brain priming itself for the arrival of the favorite portion. This anticipatory phase is initiated by temporal clues that a potential pleasurable sequence could be imminent. The same way seeing pictures of food when hungry causes people’s mouths to water in anticipation of the reward to come. Musicians have unknowingly utilized this response in order to manipulate emotional responses in listeners for centuries by disrupting the anticipated conclusion to certain sequences. This is why predictable repetitive songs “get old” so fast as the brain quickly adapts to predictable rewards the same way extreme sports enthusiasts have to constantly find new things to try or the exponential increase of addiction. Once you’ve done the same thing a couple times, the brain adapts to the predictable reward and requires something more or different for the same pleasurable response. However, the caudate nucleus is also connected to the sensory, motor and associated networks in the brain. Dopamine is also released during the emotional reaction caused by the actual desired sequence which constitutes the normal “liking” phase of the reward network. Even though dopamine is released during both of these phases, the researchers believe they travel through different sub circuits of the striatum which could cause different effects throughout the brain and body.
Past research has shown that listening to music causes an increase heart rate, blood pressure and a redirection of blood flow to the legs. The cerebellum which is very influential in all forms of movement, especially fine motor control, has an increase in activity as well. All of these activated systems and the ones discussed in this study have direct connections in influence on the sensory, motor and associated networks in the brain. Deeper research into the effects other than dopamine release music has on these systems could shed light on why humans dance. It is easy to jump to conclusion like increased blood flow to legs must be why people tap their feet while listening to music and the different effects of dopamine release throughout different phases of a song can explain why people dance differently throughout building and climax of songs. However, the affect music has on all these movement associated neurological systems must be taken into account. Most other species “dance” under a sexual context during mating, but humans can also dance for pure enjoyment unrelated to reproduction. Does the myriad of effects to systems of the brain that contribute to movement cause us to have the urge to dance? Did the benefits of dancing in a cultural setting cause us to associate music with reward or did both aspects evolve simultaneously?
There is still a vast amount of research to be done on the true cause of the pleasurable experience music brings to people. It is generally assumed that humans evolved an acuteness for specific sequences of rhythms, tones, and sounds in the process of developing language and understanding not only what, but how things are being said. However, did this appreciation for unrelated melodies develop as an unexpected consequence of these language skills, or was the reason these auditory abilities evolve simultaneously due to the sociocultural effects and benefits of music and dancing? Was the ability to bond as a distinct culture through music and dance a sufficient enough selective pressure to cause this path of evolution?