Musical development is the transformation and restatement of initial material, often contrasted with musical variation, with which it may be difficult to distinguish as a general process. However, development is carried out upon portions of material treated in many different presentations and combinations at a time, while variation depends upon one type of presentation at a time, highlighting the variation (DeLone et. al. (Eds.), 1975, chap. 1).

In this process, certain germ ideas which are repeated in different contexts or in altered form so that the mind of the listener consciously or unconciously compares the various incarnations of these ideas. Listeners may apprehend a "tension between expected and real results" (see irony,) which is one "element of surprise" in music. This practice has its roots in counterpoint, where a theme or subject might create an initial impression of a pleasing or affective sort, but would go on to further delight the mind as its contrapuntal capabities are gradually unveiled.

The musical form which traditionally exploits development to the fullest is the sonata form, though development may be used with all other forms. The use of development is what separates the sectional binary form and ternary form from sonata form.

References

• DeLone et. al. (Eds.) (1975). Aspects of Twentieth-Century Music. Englewood Cliffs, New Jersey: Prentice-Hall. ASIN 0130493465.