When God encourages violence

Like other primates, we humans have an instinctive tendency to organize ourselves into dominance hierarchies and behave in ways we feel will meet the approval of individuals we consider to be authority figures. But to a strongly-religious human, there is no higher authority figure than the deity (or deities) of his religion, even though deities are actually merely products of the imagination of other humans.

Thus, it has always seemed logical that endorsements of violence in sacred texts would encourage believers to commit actual violence in the real world. This experiment strongly suggests that this is indeed the case.