Music and language events this week

On Tuesday April 10th 3-4 pm in ILC N458, there will de a discussion of “Harmonic syntax of the 12-bar blues” by UMass Linguistics undergrad alum Jonah Katz. A link and abstract appear below.

On Friday April 13th 2:30 – 3:30 in ILC N400, Stefanie Acevedo (Yale) will present “Explaining expectation entropically: An empirical study of harmony in popular music” (abstract below).

At 3:30 Friday the 13th, David Temperley (Eastman School of Music) will present “A Model of Emotional Expression in Rock”.

All are welcome to all of these events. Please contact Joe Pater if you would like to meet with either Acevedo or Temperley while they are here.

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Jonah Katz (2017). Harmonic syntax of the 12-bar blues: a corpus study. Music Perception, 35(2), 165-192. Preprint (LingBuzz). Supplementary materials: data, statistical models, tree graphs, description of modeling.

Abstract. This paper describes the construction and analysis of a corpus of harmonic progressions from 12- bar blues forms included in the jazz repertoire collection The Real Book. A novel method of coding and analyzing such data is developed, using a notion of ‘possible harmonic change’ derived from the corpus and logit mixed-effects regression models describing the difference between actually occurring harmonic changes and possible but non-occurring ones in terms of various sets of theoretical constructs. Models using different sets of constructs are compared using the Bayesian Information Criterion, which assesses the accuracy and complexity of each model. The principal results are that: (1) transitional probabilities are better modeled using root-motion and chord- frequency information than they are using pairs of individual chords; (2) transitional probabilities are better described using a mixture model intermediate in complexity between a bigram and full trigram model; and (3) the difference between occurring and non-occurring chords is more efficiently modeled with a hierarchical, recursive context-free grammar than it is as a Markov chain. The results have implications for theories of harmony, composition, and cognition more generally.

Acevedo abstract: Given a preponderance of common _stock_ progressions in popular music, like the “Doo-Wop” (I-vi-IV-V) or the “Axis” (I-V-vi-IV) progressions, sequences of chords are often taken as a starting point for analysis. These chord sequences contextualize the sometimes _non-functional_ chord usage in popular music. While recent music-theoretical work uses computational methods to analyze harmonic probabilities in musical corpora and model their stylistic norms, it often focuses on analyzing lower-order probabilities such as single chord counts or chord-to-chord transitional probabilities. In this talk, I propose the use of information entropy, a measure of statistical uncertainty, as a way to segment harmonic progressions in a corpus of popular music (the McGill Billboard Corpus). The resultant harmonic segments are classified into prototypical chains based on functional categories that are determined by chord sequences as opposed to individual chords. The results and implications of the project are contextualized within recent research on popular music harmony and implicit learning of musical style.

Temperley abstract. In this talk, I present a framework for the analysis of emotional expression in rock music. The talk surveys some of the material in my new book The Musical Language of Rock (Oxford, 2018).

I begin with a two-dimensional model of emotion, well-established in music psychology, with valence (positive versus negative emotion) on one axis and energy (also known as arousal or activity) on the other. Valence is determined mainly by pitch collection (roughly, major versus minor, though there is more to it than that); energy depends on a variety of cues such as tempo, pitch register, loudness, and textural thickness. I then add a third dimension for complexity, or (in experiential terms) tension. Tension is affected by the density of events and also by their expectedness, with faster rhythms and low-probability events being higher in tension. Low-probability events can arise from such things as surprising harmonies, shifts outside of the currently established scale, irregular phrases, and extreme or unusual syncopations.

I then apply this model to the verse-chorus unit (VCU)—a formal section containing a verse and chorus; this is the core element of conventional rock form. We find consistent trajectories across the VCU in all three expressive dimensions—valence, energy, and tension. The chorus tends to be higher in energy than the verse; in terms of valence, many songs show a “sharp-ward” shift between verse and chorus, reflected not only in simple minor-to-major shifts but also in more subtle ways. With regard to tension, however, the peak tends to be in the middle of the VCU, either in the prechorus (if there is one) or in an extension of the verse. I present a number of examples, showing how the current model sheds light on both normative and exceptional cases.

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