Other objects in the room
Since the eight were going crazy about the paper, a few other things popped into my head they didn't think of when I was watching it...
They didn't think to look at the other objects in the room: Is the question written on the barrel of the pencils? Under the desk or the chairs? On the bottom of the guards boot?
Just places they could have looked...then it became obvious it was a test of personality. :-)