Here's an interesting study for those among us interested in adult education: Watching With Intent To Repeat Ignites Key Learning Area Of Brain. A snip:
As detailed in the Dec. 20 issue of the Journal of Neuroscience, researchers, using functional magnetic resonance imaging, found that when a person watches someone else perform a task with the intention of later replicating the observed performance, motor areas of the brain are activated in a fashion similar to that with accompanies actual movement.
I haven't looked into this in any great depth, but it seems like this info could be useful to those whose sessions involve teaching motor skills of some sort—from surgical techniques to cake decorating. (Thanks to Guy Kawasaki for the pointer.)