Electric Brain Responses to Inappropriate Harmonies During Listening to Expressive Music

Stefan Koelsch and Juul Mulder: “Electric Brain Responses to Inappropriate Harmonies During Listening to Expressive Music,” Clinical Neurophysiology, Issue 113, pp 862-869, 2002.

Review:

The processing of a pattern or a rule-based auditory stimuli in the brain has been the focus many neuroscientists’ research. This work has been primarily conducted via the investigation of linguistic stimuli. Quite recently, however, the processing of organized musical information in the brain began to be researched. Stefan Koelsch from Harvard’s Medical School and Juul Mulder from the University of Groningen have joined forces in an experiment to examine the nature of the brain’s electric responses after musical input has been interrupted by the harmonic altering of one chord in a sequence. The intensity of brain’s activity was recorded with the electroencephalogram (EEG).

In the study, eighteen participants, none of them having considerable musical training, were presented with two versions of excerpts from piano sonatas by Haydn, Mozart, Beethoven, and Schubert. The excerpts in the first group were taken from the sonatas as originally written while those in the second group had the last tonic chord altered by one raised semitone. The participants were informed about the alteration made in one of the examples and were asked to indicate the change. The study showed that only 39.6% of the participants were able to detect the alteration. The effect of a chord change caused a strong reaction over centro-temporal leads, occupying predominantly the right hemisphere of the brain. Furthermore, recorded ERP (event-related potential) waveforms showing the brain’s electrical activity over time showed early negativity as a result of introducing unexpected or altered chords on the music played to the participants. According to the authors, such occurrences reflect an interruption of the regularities characteristic for the Western European tonal system. This means that participants who noticed the effected alterations built certain expectations throughout a sequence. Given that altered chords were transposed by a semi-tone, they strongly opposed the harmonic context generated by previously heard harmonic sequences.

Response:

The study performed by Koelsch and Mulder underlines the importance of organization and regularity in the brain’s processing of environmental stimuli. However, the author’s decision to conduct the study with musically untrained participants raises the question of experience in cognitive processes. Trained musicians would score significantly higher in the test simply because they are trained to recognize harmonic relations in music. Another aspect informing the nature of cognition is context. In this case, context can be equated to genre in music. Tonic resolutions are typical not only in music of the early or late classical era; they are normative for the majority of the music genres westerners usually listen to. If for some reason participants were exposed to genres that did not use the traditional Western harmony (i.e., modal, atonal, pentatonic), the right response, even from a small percent of successful participants, would not be guaranteed. I am not stating that the above mentioned study was not performed properly; it consider necessary to note, however, that specialized domains are not suitable for studying the reactions of average people. In that sense, studies focusing on the processing of audible linguistic stimuli could present more accurate results that could be widely applied.