Stick Time: Using Scores

One of the reasons choral conductors insist that singers memorize their scores is that there is a connection between eye contact between conductor & choir and the cohesiveness of the ensemble (besides, who wants to look at the tops of heads buried in folders).  However, note that in this wonderful performance from ACDA's 2011 National Conference the choir members barely reference their scores at all.  What did the conductor do that permitted them the luxury of the score in hand for reference, yet facilitated an eyes-up approach to the concert?