I honestly don't think education is the point here. _Dogs_ don't shit where they eat. Pet rats can be persuaded to poop in their cages and not on your couch. There's some kind of pressure happening here that the researchers failed to notice. Maybe leaving the village is unsafe - girls can't walk 50m downstream to a designated toilet because they'll be attacked and raped along the way. Maybe there are tigers. Maybe a tragedy of the commons has occurred where no one is maintaining the designated toilet so it turns into a disgusting pile of feces that reeks from kilmeters away. Why would anyone want to defecate there? The river probably feels cleaner, even if they know better.