When filming, how do you acheive the "Garden State" effect,?

where one person is sitting, and in regular motion, while people are in a fast motion time lapse effect.


http://youtube.com/watch?v=ZNUK5sKtMeg like such

When filming, how do you acheive the "Garden State" effect,?
In this particular scene, Zach Braff is actually also sped up, he just doesn't happen to be moving, but you can tell by the way his head twitches a little.





But if you really wanted two elements moving at different rates of speed, you can always do it using chromakey blue or green screen.