One of the enduring contributions of the so-called American “minimalist” composers–particularly Steve Reich and Philip Glass–to global music culture was to re-introduce shape-shifting, metamorphosing aural illusions to our listening experience through intense repetition, polyrhythm and additive rhythms. These rhythmic devices are not new in music–you can certainly hear them in some African and Indonesian musics–but they were newly foregrounded in the concert hall back in the 1960s and 70s when minimalism burst onto the scene.
“Foregrounding” is an apt term in that the use of these musical devices reminds us of those perceptual puzzles from Psychology 101–like the picture of the two faces/vase that foregrounds one or the other depending on your interpretive listening stance:
A good percentage of the bliss in a vintage Reich or Glass piece derives from how the music plays with our senses, inviting the transformation of our (mis)perception to become part and parcel of the music’s affect. Reich’s early piece Drumming (1971), for instance, features perceptual artifacts the composer calls “resultant patterns” that arise out of the music’s polyrhythmic web. Reich found inspiration for this concept from his study of West African drumming. (A similar concept, “inherent patterns” was discussed by ethnomusicologist Gerhard Kubik in the early 1960s.) Musicians performing Reich’s music foreground these patterns by playing or singing them to help us along in our listening. Moreover, the careful design of the music supports our multiple and shifting interpretations: Drumming is in a 12/8 meter which can be rhythmically perceived in a variety of ways (3 groups of 4 beats, 4 groups of 3, 6 groups of 2, 2 groups of 6)–often simultaneously.
Here are excerpts from a recent performance of Drumming (and you can forward the clip to 2:00 to hear the singers’ “resultant patterns”):
Glass’s early piece Music In Twelve Parts (1971-1974) works its perceptual magic not through polyrhythms but through additive rhythms. The composer structures his piece around short rhythmic units that repeat at a steady tempo but also grow in length incrementally. Glass found inspiration for this technique from his study of Indian music with Ravi Shankar. After sufficient repetition, these repeating rhythmic blocks induce subtle perceptual shifts–playing especially with our sense of time. The music can make you feel like it’s foregrounding a slower time dimension behind its frantic surface.
Here is Music In Twelve Parts:
In both cases, the composers use minimal techniques to yield maximal perceptual results.