Contemporary Period

Why do musical styles change? The "evolution" of music is at least partly
shaped by the influence one composer has on another. These influences
are not always positive, however. Sometimes composers react against
the music of their recent past (even though they might admire it) and move
in what seems to be the opposite direction. For example, the simplified
style of the early Classical period was almost certainly a reaction to the
extreme intricacies of the late Baroque.
The late Romantic period featured its own extremes: sprawling
symphonies and tone-poems overflowing with music that seemed to
stretch harmony and melody to their limits. It is certainly possible to view
some early 20th century music as an extension of the late Romantic style,
but a great deal of it can also be interpreted as a reaction against that
style.
20th century music is a series of "isms" and "neo-isms." The primal energy
of Stravinsky's Rite of Spring has been called neo-Primitivism. The
intensely emotional tone of Schönberg's early music has been labeled
Expressionism. The return to clearly structured forms and textures has
been dubbed neo-Classicism. These terms have been employed in an
attempt to organize the diversity of styles running through the 20th
century.
Nationalism continued to be a strong musical influence in the first half of
the century. The study of folk songs enriched the music of numerous
composers, such as Ralph Vaughan Williams (England), Bela Bartok
(Hungary), Heitor Villa Lobos (Brazil) and Aaron Copland (USA). Jazz
and popular musical styles have also been tremendously influential on
"classical" composers from both the United States and Europe.
Technology has played a increasingly important role in the development of
20th century music. Composers have used recording tape as a
compositional tool (such as Steve Reich's Violin Phase). Electronically
generated sounds have been used both on their own and in combination
with traditional instruments. More recently, computer technology has been
used in a variety of ways, including manipulating the performance of
instruments in real time.