Chamber Jazz is distinguished by small, acoustic-based ensembles in which improvisation is a major factor. Though some groups are more jazz-based than others, they all tend to employ neoclassical aesthetics, particularly from the Impressionistic period and later 20th-century movements. Ethnic elements are also an important factor. These world-music leanings, however, are usually oriented toward the classical traditions of other cultures (Indian, Middle Eastern, and Asian), although South American styles also figure prominently in a lot of these recordings.