Is this the link to the Auburn study:
http://www.auburn.edu/~jml0035/index_files/Lohman_Lakin_BJEP09.pdf

Interesting details in that one especially looking at the upper and lower stanines. The following study also addresses the question of gender discrepancies in performance on the COGAT, again looking at the tails.

http://www.academia.edu/7561923/Sex...ve_reasoning_distribution_have_increased