This is one of the many recent attempts by representatives of the cognitive sciences to prove the inherent perfectibility of Homo Sapiens Sapiens. If you ask me, it's all part of one huge plot against Richard Dawkins.
I'm not only not so sure about the rather unmotivated distinction between "literary" and "popular fiction" underpinning Castano's and Comer Kidd's research. I also could offer anecdotal evidence a-plenty of sociopathic behaviour in literature departments at universities here and abroad.
Especially in literature departments at universities. Maybe Castano and Comer Kidd should redo their experiments with a new test group.