Tuesday, October 1, 2013

Interactions Between the Nucleus Accumbens and Auditory Cortices Predict Music Reward Value


I first came across this study while reading an op-ed about it in the New York Times, titled Why Music Makes Our Brain Sing. The article begins with the idea that though music is intangible, it holds incredible intrinsic value and potency. In previous studies, the author found that when music is described as highly emotional, it engages the reward system deep within our brains thereby “activating subcortical nuclei known to be important in reward, motivation and emotion.”[i] Furthermore, when we feel a peak or a climax in the music, dopamine is released. Not only does dopamine release during this peak emotional moment, but it also releases in anticipation of this moment. Dr. Zatorre and his research team decided to dig deeper into questioning what happens in our brain when we hear a piece of music for the first time. They specifically framed this in the context of online music purchasing to study what happens when someone hears a piece of music and decides to buy it.
The impact of music is generally thought to be as a result of expectancies that are created through delay, anticipation, and surprise. We can think of these expectancies perhaps in the way that great writer’s create suspense, or how composers manipulate how we expect to hear music unfold. These expectancies or anticipations of events in the music may be based on specific musical conventions or may be based on more “implicit schematic rules of how sound patterns are organized.”[ii] These expectancies are based on our own specific musical knowledge – whether transmitted or acquired – and are specific to culture and people. These ideas explain how we can enjoy familiar music, but according to the authors of the study, do not explain how previously unheard music can be enjoyed. The study seeks to determine whether there is a biological response to music based on “schematic expectancies” that are independent of explicit musical knowledge. The study was conducted using new excerpts of music that none of the study’s participants would have heard before thereby lessening any explicit predictions about the music. These excerpts were selected with the help of a music selection software. Each participant could purchase the music with their own money as a sign of whether they wanted to hear the music again.
While undergoing fMRI scanning, participants listened to each clip and placed bids of between $0 and $2 based on desirability. Contrast analysis showed which parts of the brain were active while making the purchase decisions. It also revealed what parts of the brain are activated when the music is undesirable ($0) and when it is more desirable (bids > 0).  When the music is found to be highly rewarding, a network of regions within the brain are activated. However, only the dorsal and ventral striatum showed activity that increased proportionally with the reward value of the music.
In some ways, the reward value of music is hard to qualify since it involves a combined “sensory and cognitive experience that can influence one’s affective state.”[iii] There are strong links between both sensory and affective systems. The subcortical regions and auditory sensory cortices work together to establish a rewarding stimulus. The auditory cortices are involved with extracting various sonic relationships drawing on previously heard sounds and memories of musical structures. These cortical stores in combination the nucleus accumbens can contribute to our perception of sounds as rewarding. Our musical expectancies are not just tied to harmonic or structural changes, but can also be linked to perceptions of rhythm, timbre and even changes in loudness. Overall, this study seeks to show how inherently neutral musical excerpts can be given reward value through interaction with higher order brain regions. The values placed on these sounds then influence behavioural decisions, like whether to purchase the music or not.


            This type of research has strong implications for music purchasing online since this is quickly becoming the most widespread distribution system. Understanding how and why people purchase the music they do is important for both people designing the software algorithms that recommend and sell us our music as well as for the people actually creating the music. In some ways, we live in a musical market that is quickly becoming more and more saturated. There is so much music to sift through that we spend increasingly less amounts of time listening to music. We make judgments about the music of a particular band or its inherent reward value after very short snippets of music. The consumer is empowered in new ways in this system of music distribution since increasingly, we as consumers are the ones deciding how much we want to pay for music. An example of this is the website Noisetrade.com that allows musicians to sell music on a free or PWYC basis.
            Though this study is interesting in its scope, I think there are still more factors that contribute to the musical judgments that we make. I think that the study is a bit too narrow in the assumption that the majority of our determination of the value of music is based on past musical experiences and expectant musical patterns. Often, we judge the inherent value of a particular band or artist even before we are familiar with their music. There are times when I won’t even listen to excerpts of music just based on other songs by the band that I have heard and either liked or disliked. Even our perceptions of certain styles of music are coloured by our own experiences and cultural preferences. Furthermore, we are often influenced by different value judgments that society places on music. Some bands are seen as “hipster” or “trendy.” It is often considered cool within society to have certain musical preferences. Sometimes we become pre-disposed to styles of music just because of the cool-factor associated with them.
            I wonder if the fact that carefully crafted software algorithms selected the music heightens our engagement and curiosity with it. For example, the study acknowledges that most of the excerpts selected matches the current trends and interests in the Montreal music scene – mostly dance and electronic music. So, the participants are in a way pre-disposed to like more of the music that has been selected than if a wider sample based of styles had been used. Of course this has a purpose for the study since there is a stronger likelihood the music will be a source of strong reward stimuli. However, I find that sometimes I am more pre-disposed to like particular music that is recommend to me either on iTunes or YouTube based on my typical search patterns and listening patterns just because it is recommended. In other words, I am more likely to check out the music because I feel like some sort of “Big Brother” is recommending the music as worthwhile and important. We have to be aware of how easily influenced we can be and be cognizant of the fact that not all of our decisions in terms of the value of music are actually based on musical qualities and characteristics. We often have assumptions about music that are not based on the aesthetic at all – they are based on the extramusical baggage that we carry with us.

[i] Zatorre, Robert J., and Valerie N. Salimpoor. "Why Music Makes Our Brain Sing." Editorial. The New York Times 7 June 2013. Web. 28 Sept. 2013.
[ii] Ibid.
[iii] Salimpoor, Valorie N. et. al. "Interactions Between the Nucleus Accumbens and Auditory Cortices Predict Music Reward Value." Science. 340.6129 (2012): 216-19. 12 Apr. 2013. Web. 28 Sept. 2013.

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