You'll never get an absolute number for this as humans don't see in 'frames'.
I would assume his numbers would include motion blur as that effect is not only important for 'smoothness' but also for giving a realistic feeling of movement and rotation when translated to a stationary display. If the 'player' spins around quickly you've got to blur it regardless of framerate or it just doesn't look right.
Short version: Min to simulate motion:~10Hz. Min to stop noticing flicker:~60Hz. Diminished returns on immersion:~72Hz. Limit on ability to flick your eyes and still see temporal aliasing:~2000Hz
I'm curious what conditions he's referring to with those 72 frames. Is motion blur built in for instance or are they static snapshots? 72 just seems a bit low. http://www.100fps.com/how_many_frames_can_humans_see.htm