Rapists do not differ greatly from non-rapists in their arousal with respect to rape scenarios, non-consenting and violent subject matter, however there are some features that distinguish the two. Rapists are less aroused by consenting sex as non-rapists and they are not always aroused by enthusiastic partners but reluctant ones. There are different types of rapists. Sadistic rapists are aroused by violence and non consent. Preferential rapists show an increase in arousal to violence in a sexual situation but not nonsexual violence. Undifferentiated rapists are equally aroused by rape scenes containing violence AND non sexual violence.