Scharmer, Alexandra2021-06-292021-06-292021-04https://hdl.handle.net/11299/220582University of Minnesota Ph.D. dissertation. 2021. Major: Psychology. Advisors: Mark Snyder, Marti Gonzales. 1 computer file (PDF); 98 pages.Following a vegetarian or vegan diet is associated with a wide range of positive outcomes in health, environmental, and animal-welfare domains. Although the last three decades have produced a large amount of research examining the themes in vegetarians’ and vegans’ self-professed motives, there has been a dearth of quantitative research examining these motives and connecting these motives to psychological theories. In the present studies, I (1) develop a theoretically grounded conceptualization of motives to follow a plant-based diet, (2) create a psychometrically validated instrument with which to measure these motives, (3) expand these constructs to encapsulate omnivores’ motives for reducing their meat consumption, and (4) design a psychological intervention aimed at decreasing omnivores’ meat consumption using persuasive messages matched to individuals’ own motives for reducing meat consumption. I found that a four-factor model of motives (animal welfare, environmental, health, social) best describes the data and fits with functionalist theory. Then, I tested whether matching to these motives in omnivores resulted in greater intentions to reduce meat consumption, more negative attitudes towards meat, and selecting meat-free options for a hypothetical meal. I found limited evidence for a matching effect but did find some evidence that environmental appeals are generally more effective than other types of persuasive messages.enfunctionalismmessage matchingpersuasionsustainabilityveganismvegetarianismThesis or Dissertation