Singing as We Speak (And Processing It Too)
Close your eyes and imagine the sound of someone talking. Easy, right? It’s something that we hear every day. Now, close your eyes and imagine the sound of someone singing — it’s probably pretty different, no surprises there. Just out of curiosity, what exactly is different about it? Is it sort of like talking, with some key distinctions?
Listen, maybe you don’t see eye to eye with Buddy the Elf, and that’s your prerogative. Most of us will probably tend to agree that singing can be thought of as something of a midpoint between speech and music. After all, it’s us using our voice to create music.
Let’s shift our attention over to neuroscience for a second: if we’re assuming that singing is some intermediate form of expression, does that mean anything with respect to the way it is processed in the brain? If it does, maybe we should expect to see some sort of novel pattern in associated neural activity.
To begin to unpack this question, let’s first understand how the brain processes music. It is important to note that if preferential activation of the same region of the brain follows from a given stimulus, it suggests a functional role in processing. With this in mind, fMRI scans of 24 healthy young adults were conducted as part of a 2018 study by researchers at McGill University. Participants were asked to listen to audio samples including music (both instrumental and a cappella) and non-musical recordings of spoken language. The data showed that regardless of the presence of vocals, listening to music led to activation of different regions of the superior temporal gyrus (STG). Amunts writes that while this region generally functions to integrate sensory information, because it contains the entire auditory cortex, it is especially important for the consolidation of auditory stimuli. Participants’ responses to samples containing only voices were markedly different, characterized primarily by activation in a region of the brain known as the superior temporal sulcus (STS). This pattern of engagement was noted for both musical (a cappella) and non musical (speech) samples, which suggests that it is the acoustic characteristics of the voice that lead to different processing pathways in the brain, such as the STS. This all is is depicted in the figure below: in terms of where activity is localized (left diagram) and also in terms of how different stimuli categories relate to one other (right scatterplot: instrumental music in red, singing in blue, speech in green).
We’ve established that there are discrete anatomical differences in the processing of music (instrumental or accompanied singing) vs. the voice in isolation (speech or a cappella music). The former is associated more with the STG, and the latter with the STS. Now, we can address our initial question. How can we compare the processing of unaccompanied singing as compared to non-musical vocal samples and music? The same researchers found that instead of purely one or the other, it is linked to preferential activation of both the STG and the STS. This is reflective of the fact that singing exists somewhere between speech and music, encoding characteristics of both - which on their own would be associated with activity in either the STG or STS.
On the topic of the neural basis of how unaccompanied vocal music is processed, a separate 2022 MIT study was able to delineate this in even greater detail. Their study made use of electrocorticography, a neuroimaging technique prized for its exceptional spatial resolution and acuity, and less so for its convenience.
In practice, researchers exploring topics like this aren’t really going around opening people’s brains up. Electrocorticography is employed in specific limited situations, like in cases where a patient must undergo a neurosurgical procedure. Here, electrodes record cortical activity directly from the brain’s surface, making it one of the more invasive recording techniques neuroscientists have at their disposal. The specificity it affords however led researchers to discover a cluster of neurons within the auditory cortex (which again, is entirely localized within the STG and communicates with the STS) that fire preferentially in response to singing — not speech, or instrumental music, but specifically unaccompanied vocal music. This serves as another point of evidence that the brain has specific means by which to identify and process singing, even from other kinds of music or vocal stimuli.
So, regardless of how exactly you may conceptualize the difference between singing, talking or even music itself, our brains could have some level of an anatomical basis for specifically understanding this difference. fMRI data suggests that different regions of the brain (the STG vs. the STS) activate on something of a spectrum that stretches from music to speech, with singing falling somewhere in between. Moreover, a specific cluster of neurons may share responsibility for processing this distinction between singing and non-musical vocal stimuli/music. It certainly is interesting to consider how singing, which is such an important and profound human experience, has such a discrete physiological basis for identification. Charles Darwin even suggested that early humans sang songs of love to one another, long before the development of more standardized, mutually understood language.
And just for the record — yes, there is singing in the North Pole.
Sources
- Amunts, K. (n.d.). Superior temporal gyrus. Superior Temporal Gyrus — an overview | ScienceDirect Topics. https://www.sciencedirect.com/topics/neuroscience/superior-temporal-gyrus
- Liberman, Mark. Language Log: Darwin and Deacon on Love and Language. Itre.cis.upenn.edu, 14 Feb. 2004 itre.cis.upenn.edu/~myl/languagelog/archives/000453.html
- Massachusetts Institute of Technology, 2022, February 22. Singing in the brain: Neuroscientists have identified a population of neurons in the human brain that respond to singing but not other types of music. ScienceDaily. www.sciencedaily.com/releases/2022/02/220222121221.htm
- Whitehead JC, Armony JL. Singing in the brain: Neural representation of music and voice as revealed by fMRI. Hum Brain Mapp. 2018;39:4913–4924. 10.1002/hbm.24333
