As a real scientist, mpdivo's comment makes me want to climb a clocktower with a rifle. Science does not prove anything ... ever. Science can only disprove, and even that might be debatable.

Assuming such study exists, I believe the educated way of saying it would be: "A social science study out there showed a correlation between being a loot whore in games and being a bad person in real life." (I tried to preserve as much of the original wording as possible)