Expecting the Unexpected in Music
What is a wrong note anyway? You may get very different answers depending on who you ask. The great jazz pianist Thelonious Monk famously proclaimed, “The piano ain’t got no wrong notes.” While I am not so certain that Arturo Toscanini would agree with that sentiment, I find that I have always been drawn to music that tastefully defies my expectations harmonically.
One great example of a song that features a distinctly subversive harmonic moment is one that I imagine almost everyone living in the United States has been exposed to at some point in their lives: Sleigh Ride by Leroy Anderson. Despite having mass appeal in large part to its accessible and catchy melody, Sleigh Ride features a very atypical key change in its B section (giddy up, giddy up, giddy up, let’s go). Up until this point, the harmony of the song has markedly prepared our ears for the key of G major — all of the tension and resolution we hear brings us back cleanly to our tonic, home base G major chord. Going into the B section however, Anderson abruptly changes keys from G to B by moving from our tonic G major to a C# minor 7 chord. Not only is the relationship between the roots of these chords is a tritone, classically thought to be the most dissonant interval, but the two keys involved are disparate as well. Pictured below is the circle of fifths, which organizes keys’ similarity based on their proximity. We can see that that G and B are nearly on opposite sides.
Given the commercial and cultural success of Sleigh Ride, it seems that I am far from being the only one that enjoys this type of harmony. So how can we understand why this might be the case? Is there any kind of a basis for enjoying harmony that catches us off guard in this way?
It turns out that there is.
For starters, researchers at McGill university sought to investigate the relationship between enjoyment of music and reward prediction error, which is a measure of the disparity between an anticipated and actual reward. They designed a task wherein participants are asked to select both a color and direction as their brain activity is simultaneously recorded using a technique called fMRI. The choice made had a unique probability of producing an excerpt of music that was consonant and enjoyable or dissonant and unenjoyable, and over time, participants are supposed to associate certain choices with certain outcomes. By using an algorithm designed to measure the reward prediction error of choices made by participants and comparing that to anatomical data collected from the fMRI, researchers were able to identify a striking relationship. It turns out that when participants were less able to predict the outcome of their choice, increased activity in the nucleus accumbens was observed. This is a region of the brain that past studies have tied to concrete, palpable rewards like food. Importantly, this is the first study to demonstrate a connection between this region and an aesthetic pleasure like music, suggesting that the element of surprise in music is capable of creating a distinct reward response.
On the topic of music that challenges our expectations as listeners, there exists a body of research that deals with harmony that features notes that are outside of keys. One such study published in Volume 151 of the Brain and Cognition journal involved measuring participants’ fMRI responses of three distinct categories of auditory samples: those featuring chromatic harmony, diatonic harmony, and atonal harmony. Chromatic harmony is distinguished for the purposes of this study as containing notes outside of the established key of a particular passage. Diatonic harmony contains only notes from within the key, and atonal music contains no real tonal center. In analyzing data collected from the fMRI, researchers found that certain frontal regions of the brain, such as the dorsolateral prefrontal cortex (DLPFC) and inferior frontal gyrus (IFG), were preferentially activated in response to chromatic music. Again, this is thought to be linked to prediction error. When we listen to music, we are constantly creating and updating a model of what will happen next. Chromatic music, which features notes out of key, will feature the most prediction error because our musical expectations are going to be based around note possibilities that exist in the bounds of our home base key. Consequently, our expectations will be defied more so than in diatonic music, which only features in key notes, which we should expect more, or in atonal music, where the lack of a key center prevents predictions from being made in the first place.
There is longstanding precedent in music theory of techniques designed to subvert the expectation of a listener. We see this as far back as classical music with the idea of a “deceptive cadence,” which essentially involves resolution to a chord other than the expected tonic home key. The development of music since then has been marked in part by pushing the envelope of harmony and exploring note choices outside of a given key center, as evidenced by the development of jazz and musician Jacob Collier’s 12 note chord, which utilizes every note of the chromatic scale and teaches us that if you are unsure of what notes to add to a chord, you should maybe just add them all. It is fascinating however to see that there is a discrete neural basis to the perception of this music that defies our expectations and our brain’s ability to predict what will happen next in a song, and even more so, it may be linked to enjoyment specifically.
And maybe, in studying the elements of our appreciation for music, a phenomenon that is so characteristically human, we are afforded a greater understanding of our very humanity.
References
Li, Chia-Wei, et al. “Predictive Processing, Cognitive Control, and Tonality Stability of Music: An FMRI Study of Chromatic Harmony.” Brain and Cognition, vol. 151, no. 151, 1 July 2021, p. 105751, pubmed.ncbi.nlm.nih.gov/33991840/, 10.1016/j.bandc.2021.105751. Accessed 12 Dec. 2022.
Longdon, Victoria. “What Is the Circle of Fifths?” Classic FM, 22 May 2020, www.classicfm.com/discover-music/music-theory/what-is-the-circle-of-fifths/. Accessed 10 Dec. 2022.
McGill University. “The Unexpected Creates Reward When Listening to Music: Scientists Prove Difference between Expected/Actual Outcomes Cause Reward Response.” ScienceDaily, 12 Feb. 2019, www.sciencedaily.com/releases/2019/02/190212134120.htm. Accessed 12 Dec. 2022.
Association for Psychological Science. (2021, August 19). The brain’s ‘prediction machine’ anticipates the future when listening to music. ScienceDaily. Retrieved December 11, 2022 from www.sciencedaily.com/releases/2021/08/210819195024.htm
