Review of "This is your brain on music" by Daniel Levitin - Part 3

Chapter 3 is where Levitin starts involving the reader in the neural correlates of music cognition. The gross functional generalizations of the four lobes of the brain (frontal, parietal, temporal, and occipital) are mentioned, along with the older/reptilian brain. It is nice reading about the several functional processes involved in different kinds of musical activity - perception, memory (both working memory and long-term memory), attention, motor control during performance and listening, and of course...emotion. Levitin highlights the fact that almost every neural center in the brain has a part to play for perceiving, recognizing, reading and performing music....vocal or instrumental. Another interesting thing to note is the similarity between music and language in the way they are organized and perceived, as well as the neural correlates they share such as Broca's area and Wernicke's area.

Two final points of interest in this chapter are 1) perception is the end product of a long chain of neural events, and is not instantaneous; 2) perception need not always be correct....our brain can actually misinform us and fool us into believing something.
It is just amazing thinking about how complex an activity "perception" is, and how our brains have evolved to respond to the requirements of perception with incredible efficiency.....something that most of us take for granted. However, in order to achieve this kind of efficiency, there has to be some kind of trade-off in accuracy. Our brain uses stored information, does some kind of probabilistic computation to complete/fill in perceived bottom-up information with top-down context. This is what enables us to "expect" things....in a lot of cases subconsciously.

This brings us to the interesting topic of auditory as well as musical illusions analogous to visual illusions such as the Ponzo and Kaniza illusions. The book led me to investigate Sardinian acapella music for the first time. (Unfortunately, I could not decipher/perceive the illusion, although I really liked the music). But I came across other auditory illusions with respect to melody, where the pitches were segregated into different ordered patterns for the right and left ear involving high and low pitches. But when heard, we perceive the segregation different from the actual order (we tend to group lower pitches as perceived by one ear, and higher pitches as perceived by another). This definitely needs to be tried out with earphones.

I will finish my review of "This is your brain on music" within my next two blogs. If you still haven't purchased the book, or at least checked it out from your local library.......you are seriously missing out!

Review of "This is your brain on music" by Daniel Levitin - Part 2

In Chapter 1, What is Music?: From Pitch to Timbre, Levitin provides an excellent, concise yet lucid overview of the basic elements of sound pertaining to music (tone, pitch, rhythm, tempo, contour, timbre, loudness, spatial location, reverberation etc.), from a psychoacoustics perspective, useful to both musicians and non-musicians. He then proceeds to define the higher order elements made of these basic elements, such as meter, key, melody and harmony. The higher levels of our brain process the relationships between these elements in a coherent and cohesive way. The relationships are important not only from the standpoint of how notes feature in music, but also how they do not. To illustrate this point, Levitin uses a visual art metaphor through an example. “Miles Davis….described his improvisational technique as parallel to the way that Picasso described his use of canvas: The most critical aspect of the work, both artists said, was not the objects themselves, but the space between the objects.” According to Levitin, the most important part of Miles’s work was the empty space between the notes. Miles’ genius lay in his ability to know precisely when to hit the next note, giving the listener enough time to anticipate.

I couldn't help but think of Jeff Beck in this context. An extremely underrated guitar player who superbly uses space to emote. I found his guitar playing constantly evolve over time in comparison to his contemporary old school blues-based guitarists such as Jimmy Page, and Clapton.

Levitin interestingly approaches sound as a relative, non-absolute phenomenon. According to Levitin, pitch is an internal image of the end product of a chain of mechanical and neurochemical events caused by sound waves impinging on the eardrums and pinnae. The difference between Levitin's view from other physicists is that while most physicists agree that "pitch" is a mental percept, they consider sound to be absolute on account of vibrating molecules, irrespective of whether it is perceived or not.

Levitin talks about melody as an auditory object that remains invariant in spite of transformations along some of the basic elements of sound, similar to the invariance of objects in the visual domain. Although the areas of the brain that respond to individual pitches have been mapped, we do not know the neurological basis for key invariance, where transposed melodies sound perceptually equivalent.

In Chapter 2, Foot Tapping: Discerning Rhythm, Loudness, and Harmony; Levitin explains how we use various areas of our brain to discern rhythm, and to perform rhythmically. These areas include the cerebellum and basal ganglia, higher cognitive regions such as the motor cortex, and the frontal lobes for planning. He explains the difference between rhythm, meter, and tempo – related but often confused concepts, and how we use our brain to perceive these concepts. I was thrilled to see him spend some time talking about musicians' use of syncopation to play with listener's emotions and expectations. Our amazing ability to segregate sounds and group sounds based on the situation (The Cocktail party example), for performing auditory scene analysis is mentioned.

Review of "This is your brain on music" by Daniel Levitin - Part 1

Although, I was already intimately involved with music both academically (through research and modeling of certain aspects of specific performers, by way of case studies), and as a guitar player in various bands, the book that really turned me on to the neural correlates of music cognition was Daniel Levitin's, "This is Your Brain on Music - The Science of a Human Obsession."

While Levitin's book is intended for a general audience, it provides several avenues of interest for the serious music cognition researcher as well. What makes Levitin's style unique, yet personal and thoroughly engaging is his immensely, well-rounded experience in music as a performer/musician, recording engineer in the music industry, as well as researcher and academician. To make his point, he provides several relevant examples from mainstream genres such as classic rock, R&B, soul, and pop.

Another point worth mentioning is the fact that Levitin's interest is in cognitive systems and not just in neuroscience itself. So his research is in no way reductionist. He makes his intentions very clear by stating that his interest in neuroscience is to understand the functional aspects behind cognitive processes. This view is reflected well throughout the book when he consistently connects functional processes pertaining to memory, categorization, emotion, attention etc. to existing paradigms in experimental psychology as well as various neural correlates.

The book also provides a window to the music cognition research community. It helps acquaint even the general reader to several key researchers such as Peretz, Zatorre, Janata, Tillman, Trehub, in a non-pedantic way. In my next few blogs I will provide a deeper overview of some of the chapters in this book.

If you are even remotely interested in music in any way (avid listener, performer, teacher, researcher), you should have purchased this book already!!!

Welcome to the musical brain!

Given that music is a temporal activity, the perception and recognition of music elicit strong comparisons with spoken-word recognition. The difference between the two however is that spoken-word recognition has been an active area of study since the late 70s with highly influential psychological models published by scientists such as McClelland, and Marslen-Wilson, while music as a separate field of psychological study is just about gaining ground.

I find Marslen-Wilson's initial and revised versions of the cohort model appealing because of their explicit way of separating bottom-up sensory information from top-down context related effects, and providing specific rules for constraining the influence of context during recognition. Spoken-word recognition has several examples of context influencing recognition, such as the phoneme restoration effect. Intuitively, recognizing melodies follows a similar set of functional processes as speech. I know based on anecdotal experience that partial melodies are enough to enable mentally filling in and humming the rest of the melody. However, one of the problems I have faced is that of finding examples in melody recognition suggesting contextual effects consistent with the phoneme restoration effect in speech. On a positive note, experimental evidence based on the gated presentation of melodies (Dalla Bella et al.) does suggest that the recognition of melodies involves combination of bottom-up pitch-related information with top-down context.