A 1982 study by Zillman and Bryant found that increasing exposure to pornography increased viewers' callousness to the sexual abuse of women, including the trivialization of rape. An examination of the work by Malamuth, Donnerstein, Linz, and Penrod indicates that scenes of rape and other forms of violence against women can increase viewers' acceptance of rape myths and also increase male viewers' aggression against women. Given that empirical studies show that pornography leads to harmful acts against women, certain civil remedies are available. MacKinnon (1985) reasons that pornography is a form of sex discrimination, since it exploits and subordinates based on sex and differentially harms women. Such an approach to pornography is found in the Minneapolis, Indianapolis, and proposed Los Angeles County ordinances. Another civil remedy for pornography's harm is in group libel laws, which establish liability for the publication of material that degrades certain groups in a way that produces breach of the peace or riots. Pornography and its effects can be shown to violate such laws. The group libel approach is used in Norway and has been found constitutional in the United States, although it was intended to apply to racial defamation. The civil remedy of product liability is based on tort law which holds the manufacturer of a product is liable if it can be shown that the product has harmed someone. It can be claimed that products portraying sexual violence stimulate consumers of the product to inflict injury on innocent victims. Nineteen references are listed.