'Thriller' Dance Question?

Question:How come in clips like this one below, MJ and the zombies start the head side thing right away?
http://www.youtube.com/watch?v=XDSojuMUJ...
Where in this clip, the zombies move back and forward a couple times before doing the head side thing?
http://www.youtube.com/watch?v=RL0YxRkCp...
Are there different versions of the dance (song)?

Best Answer - Chosen by Asker: How come in clips like this one below, MJ and the zombies start the head side thing right away?
http://www.youtube.com/watch?v=XDSojuMUJ...
Where in this clip, the zombies move back and forward a couple times before doing the head side thing?
http://www.youtube.com/watch?v=RL0YxRkCp...
Are there different versions of the dance (song)?

the 2nd one may not be doing the proper version.....they arent in the actual video!!!
you can adapt it you know!!
hope it kinda helped!! =D
therefore yes there will be millions of versions of the dance but if you want to learn it stick to the original video

Are you serious? Isn't the answer obvious? I have to give you a "DUH AWARD" on this question!

This is so obvious. Of course there are more than one version of the dance. People adapt dances.
If you watch the movie 13 going on 30 they have a version of the dance.
The first one was the real original version though and the second one was an adapted version.