At 15:00, he mentions research on the efficiency of gestures done in the 60's. Does anyone know what he's referring to?
It allows one to draw CAD drawings, convert drawn letters into labels, etc in a more natural way.
As far as I know, Alan also greatly admires the work done at MIT in the 1970s like http://www.paulmckevitt.com/cre333/papers/putthatthere.pdf