Why are the formal principals of statement repetition contrast and variation important in musical compositions?

Answer 1

The terms "statement", "repetition", "contrast" and "variation" are usually applied to melody but the principals apply equally to rhythmic structure, timbre, voicing etc.

Statement: The first appearance of a melody in its complete form is the statement. Every piece of melodic music has a statement, by definition. A melody can be prefigured or hinted at before its first full statement.

Repetition: Human perception relies to a very large extent on pattern recognition. When we see or hear something several times we feel comfortable and familiar and we start to make deductions or inferences. If you make a very short recording of some random banging on a drum it just sounds random but if you loop the recording a rhythm emerges. What is the difference? Only that we recognise the pattern and pattern is inherently important to us.

Contrast: We need pattern recognition to find food, recognise family members, run from predators etc but there is so much in the world that can be read as pattern we would be overwhelmed unless we also learned to discriminate and dismiss unimportant or trivial patterns. The looped recording of the random drum beats will hold our interest for only a few seconds. The more different the new thing that takes our attention, the more we notice the qualities of both. Another aspect of pattern recognition is that we most notice differences. If you're pointing out a friend in a group of four people, three of whom are black, three are medium height and and three are medium weight, you'll say "he's the white guy" or "the short guy" or "the fat guy". Hence two different melodies in the same key and rhythmic structure and we'll notice the tune while probably paying much less attention to the other qualities. In this way a composer can draw attention to specific aspects of the music.

Variation: Having established a pattern by repeititon, small changes to it noticed and perceived as part of a whole with the pattern. They are perceived as growth or development. A mother recognises her baby from day to day as it grows and she most notices the changes, the new things it can do, the first tooth and so on. Again this kind of recognition is hard wired into us. Having spotted a pattern of growth, we start to make predictions about the direction of change - we get a sense of where it is going. The composer can play with this perception by making us feel comfortable or by violating our expectations for amusement, surprise or shock.

The necessity of repeition and variation and contrast leads to philosophical/aesthetic differences. "Excessive" repetition such as is found in clubbing music is often dismissed as immature and yet it is obvious that clubbers derive much pleasure from it. Luis-Manuel Garcia has pointedout (in http://www.societymusictheory.org/mto/issues/mto.05.11.4/mto.05.11.4.garcia.HTML) that Schoenberg saw both sides of the argument at different times. He said his ideal listener was a 'wakeful and trained' mind; one that has no wish to be insulted by having the same musical idea presented to him repeatedly but in Die Grundlagen der musikalischen Komposition he points out that "comprehensibility in music seems to be impossible without repetition".

Since writing the above, a friend has commented: "Statement in music has always been more represented by the delivery, a person, a face, a lyrical phrase, that kind of thing. Statement could be a broader term for what the music actually represents as a whole." However, dolmetsch.com agrees with me, giving "statement" as a synonym for "exposition" and defining it thus: "the part of a work, in sonata form, where the principal themes are first stated, or in a fugue, where the voices first enter".