Different airline, but I noticed when watching this video a while ago that (at 12:45) the instant Rotate is called she looks down and focuses solely on the FD.
Very interesting video. Especially in connection with discussed topic. The FO is performing ideally looking takeoff with FDs perfectly centered... focusing on PFD from the very start of rotation. IMHO this is not normal - I believe you should continue to look outside during the rotation.
A-320 FCTM says: "To monitor the rotation, the PF uses the outside visual references. Once airborne, the PF controls the pitch attitude target on the PFD."
I don't have my own videos like this (will try to make them later), but I was able to find similar video on youtube. Search for "GENOA LIMJ Boeing 737 TAKEOFF" 2:20 duration, the precise moment is at 1:06.
Clearly the FO is looking outside at least during the initial part of rotation.