The scientific literature and advocacy organisations highlight three harm-related arguments as paramount reasons for the reduction and cessation of the consumption of animal-derived products (ADP) - violence toward animals, damage to the environment, and human health. However, research on their comparative effects is scarce and there is no clear definition of which type of argument is the most effective in restricting ADP consumption. Based on cognitive dissonance theory, this study aimed to investigate the effects of these types of arguments on meat-eaters' attitudes and beliefs toward the propositions of reducing and ceasing ADP consumption. The study sample comprised 545 Brazilian adults. We adopted an experimental between-subjects design based on the presentation of vignettes. Each participant responded to one of the vignettes (animal rights, environmental, or health arguments) or a control condition. Results showed that greater levels of ADP-related dissonance provoked greater positive attitudes toward the reduction and cessation of ADP consumption. Compared to baseline, the animal rights and environmental messages significantly increased dissonance and positive attitudes toward ADP restriction, but not the health argument. Participants most frequently adopted the dissonance-management strategies of denial of responsibility, denial of harm, and the articulation of beliefs favourable to change. The discussion highlights that the different effects of social influence contexts and argument types depend on their capacity to reveal ADP consumption as morally problematic behaviour. To our knowledge, this is the first study to experimentally compare the effects of animal rights, environmental and health-related arguments in generating ADP-related dissonance and attitude change.
