 These theorists often follow social science researchers in drawing more fine-grained distinctions within the general category of pornography (i.e., the sexually explicit material whose primary function is to produce sexual arousal in those who view or read them). They often distinguish between 1) violent pornography, 2) non-violent but degrading pornography, and 3) non-violent and non-degrading pornography, since there is some evidence to suggest that some of these materials (e.g., in categories 1 and 2) may be harmful in ways that other material (e.g., category 3) is not.