1.7 Expository and developmental  (Page 2/3)

Later in the movement, Mozart creates a developmental passage based entirely on the upward motion withwhich the theme begins. Only fragments occur; the complete theme is never stated.

The fourth movement of Dmitri Shostakovich’s String Quartet No. 2 introduces a long, lyrical theme, playedseveral times in its entirety.

In a subsequent developmental section, the theme is broken into fragments that get shorter and shorter: at onepoint, the theme is reduced to just two notes. As in the Mozart developmental passage, the complete theme is never stated.

Other musical features help to differentiate expository and developmental sections. In expository passages, theprimary activity is often concentrated in one instrument or register. In development passages, multiple instruments andregisters may trade the musical ideas back and forth, in dialogue or competition.

In the first movement of Mozart’s Symphony No. 40 in g-minor, the violins introduce the primary theme.

In a subsequent developmental section, the violins repeatedly play a fragment of the theme, gradually sinkingin register. Suddenly, the music becomes far more turbulent as the fragment is traded between the violins and celli.

In the brief Intermède from Olivier Messaien’s Quartet for the End of Time, the main theme is initially presentedfixed in register.

As the theme is developed, fragments of the theme shift in register:

Expository sections tend to be more predictable. On the other hand, development sections are oftenunpredictable and irregular, with abrupt changes of texture, dynamics, rhythm, etc.

For instance, the Finale of Beethoven’s Symphony No. 8 opens with a vivacious expository section,interrupted only by a few brief hesitations.

In a later developmental section, the hesitations are exaggerated and disrupt the flow of themusic.

In the fourth movement of Bela Bartok’s String Quartet No. 4, each player takes a turn playing the plucked theme.Occasional chords underlie the theme’s presentation.

In a subsequent developmental passage, the chords are brought to the fore, becoming more forceful and abrupt.These and silences irregularly disrupt the music’s flow. Only fragments of the theme are played, and the instruments alternatemore rapidly.

In expository sections, there is usually only one theme or musical idea presented at a time. In developmentalsections, multiple themes may be presented simultaneously.

Paul Dukas’ The Sorcerer’s Apprentice tells the story of a wizard’s assistant (played by Mickey Mouse inDisney’s "Fantasia") who, rather than clean his master’s lair himself, furtively casts a spell that rouses the mops, pails andbrooms.

As each tool is wakened, Dukas introduces a new theme:

Unfortunately, the apprentice isn’t able to command the tools. As chaos ensues, Dukas combines the two themes,creating a developmental pandemonium:

In Alban Berg’s annotated score of the "Lyric Suite," the composer describes the second movement as a domesticscene in which his married love interest, Hanna Fuchs-Robettin, is playing with her two children. Each family member is given atheme: