In William Butler Yeats' poem "Among School Children" the poet famously asks "How can we know the dancer from the dance"? Many interpret this line as an observation that some creative acts are so intimately connected to the artist who created them that separating the two is almost impossible. However interesting or beautiful this idea might be, its reality makes the work of dance preservation a difficult one. Literary or musical art can be transcribed to paper using a widely understood encoding system (e.g. the alphabet) and passed on to future generations. Documenting and preserving dance is not so easy.
Some choreographers have developed written notational systems like those used to transcribe music. The most common of these systems are those descended from the work of the early twentieth-century Hungarian dancer Rudolph von Laban. Although these system are learned and understood by many dance artists and scholars, literacy is far from universal and only a relatively small subset of dances have been completely transcribed in any system.
The oldest method of dance preservation is, as with most art forms, oral tradition. Masters of the craft teach their students who carry it into the future. Most surving pre-19th century dance exists today only because of this practice. In recent history, companies like The American Dance Machine have attempted to preserve early twentieth century theatrical dance by learning and performing the works of the previous generation.
Since the mid-twentieth century, many dances have been documented with video recording. Unlike written words or musical notes which encode sound by abstraction and are understood only by shared conventions, video transcribes the sensory experience itself and requires no special education to interpret. NYPL has one of the largest collections of dance video in the world at the Library for the Performing Arts. Although video has a few obvious advantages over oral tradition or abstract notional systems, it is in other ways more limited. The technology forces the videographer to select focus and perspective and so flattens the experience of a dance from three to two diminensions and narrows the expansive view of a stage to the small confines of a video screen. Some choreographers and scientists (such as William Forsthye and Ohio State University's Advanced Computing Center for the Arts and Design [ACCAD]) have developed tools to allow an audience to switch between multiple synchronized camera views, but recording and presenting dance in this way is time consuming and expensive and only captures a limited number of perspectives on the dance.
Today, librarians, dancers, and scientists are working to develop new ways to more fully document this fundamentally ephemeral art form. Some have experimented with motion capture technology (such as that used by Peter Jackson's special effects team to create the character of Gollum in The Lord of the Rings) to fully document the movement of dance (again ACAAD's work is among the most interesting). Others are using electroencephalography [EEG] technology (normally used for medical diagnosis) to document the electrical activity in the brain during the performance of a dance. None of these technologies replace the older forms (dances are still regularly preserved by teachers training their students), but new technologies may help to preserve those portions of a dance that are missed by other techniques.
If this topic is of interest to you, you may want to take a bus or train down to Washington D.C. on May 16. From 7-10 pm I and a group of dancers, technologists, and curators are holding a free, public workshop at the Kennedy Center to discuss these issues (the culmination of a series of workshops sponsored by the Maryland Institute for Technology in the Humanities at the University of Maryland, College Park; Ohio State University; and George Washington University). It should be a great event, and our hope is to begin a discussion that will further improve our culture's approach to the very difficult task of dance documentation. Hope to see you there!