Riffing by a choreography is a term sometimes used to describe a form of improvisation where a choreography observes his or her dancers and appropriates their movement then using it as a base develops it further.  By running someone else’s movement through their own body a choreographer may stimulate new ideas they might not have had just by watching or thinking about a movement.  To study the importance of this idea – of running movement through the body to get a feel for its physical possibilities  - we analyzed video data from three large captures of choreographic dance making.  The special value of running a movement through the body is an instance of the more general claim that there is a difference between participant knowledge – the knowledge an agent acquires by being the cause of an action – and observer knowledge – the knowledge an observer acquires through close attention to someone else’s performance.  It may seem obvious that there must be a difference be acting vs watching. But the idea that there might be no difference has been challenged by recent findings about the action observation network and tacitly challenged by certain tenets in enactive perception. We explored why a choreographer ‘riff’s’ when appropriating and evaluating the movements of his dancers. By recruiting his body to help him cognize he is able to understand the possibilities of movement better than observation. He acquires participant knowledge.

When the dancers we studied are working on an assigned choreographic task, or when working on a duet, trio or quartet, we regularly observed that the choreographer, WM, would observe them closely, and then, if the dancers were to do something interesting or untoward, he would try out their movement himself. He would physically sketch the movement, appropriate what he likes, and then work on the phrase himself, substantially modifying it before sharing it.  We call this activity riffing off-of-others.  Superficially, it is the equivalent of playing a musical piece himself.