what is this "compressed sound effect" called?

it's in this song: http://www.youtube.com/watch?v=qzU9OrZlKb8 at 3:08
the song goes from like regular (the rest of the song) and then turns
like, compressed, around 3:08.
i really like that compressed noise sound effect. does anyone know
what it's called? thanks.

by the way, i hate britney spears. this is just the first example i
could find.