 Dance philosophers have also identified other forms of dance improvisation that do not fit within Carter’s three categories. Kent de Spain (2003), for example, brings our attention to a type of dance improvisation that is practiced by dancers in order to achieve a movement-based somatic state, what we shall call “somatic improvisation”. Somatic improvisation, or the results of these improvisational exercises, may be included in a theater performance for an audience but need not be. Constance Valis Hill (2003) includes “challenge dance” performances, stemming from the African-American tradition of dance “battles”, where the purpose is to win an ever-escalating competition of skill and style. Like somatic improvisation, challenge dance improvisation can be offered for audience appreciation in a concert context but need not be—it has taken place in social and street settings, for entertainment as well as for “artistic” purposes. Aili Bresnahan (2014a) has made the claim that all live dance performance involves improvisational artistry to at least some extent and that this can be seen as a kind of embodied and extended agency under embodied and extended mind theories, in particular that of Andy Clark in his book, Supersizing the Mind: Embodiment, Action, and Cognitive Extension (2011).