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Summary: In the four sections of this post, I:

  • Introduce cognitive dissonance theory
  • Review (what I interpret to be) the "main themes" of the literature on the cognitive dissonance of veg*nism/speciesism
  • Draw some conclusions
  • Dump some other factoids I came across when reading the literature

Cognitive Dissonance Theory

Cognitive dissonance theory was put forth in (Festinger 1957) and has been called “social psychology's most notable achievement” (Zukier 1989). Of course, we should caution that, of all the areas of social science, social psychology has been among the hardest hit by the replication crisis. Indeed, most research on cognitive dissonance theory is not any more methodologically rigorous than the rest of the field, at times verging on unfalsifiability. On the other hand, the theory does make concrete, surprising, and correct predictions, even if most of the studies containing those results have yet to be put under the proper scope of replication in this decade (Vaidis and Bran 2019). My personal opinion is that the core of the theory, and its relevance here, will stand the test of time, but skepticism is encouraged (especially about any specific study I cite).

Roughly speaking, the theory holds that mental discomfort exists in a person who acts in a way inconsistent with their beliefs. The magnitude of this “cognitive dissonance”, which varies with the salience of both the action and belief, as well as the discrepancy between them, motivates the person to reduce this dissonance. The dissonance reduction strategies available to an individual can be put in the following trilemma:

a) Change the action/behavior

b) Change the belief/attitude

c) Dissociate the two, often through avoidance and compartmentalization

In a modern reference on the theory, Cooper (2007:7) gives the example of someone who believes the poor deserve their charity, but does not donate as such. Typically, this does not produce dissonance, as long as the person does not entangle the questions “how do I spend my money?” and “do I care about poor people?” However, if one day a charity worker knocks on their door soliciting donations, this compartmentalization collapses, leaving (a) and (b) as the primary options. Thus, our subject is left to either abandon their belief that they care about poor people, or donate a sum of money commensurate with this belief.

Cooper (2007:8) goes on to extend the example:

I have already refused to give any money to a beggar and I gave only a few coins to the soup kitchen. That’s the reality, and the reality has limited my choices about how to resolve the discrepancy. It is difficult to distort the reality of my behavior. My cognition about my attitude, on the other hand, is more fluid and flexible. If I come to believe I don’t really support giving money to the poor, then my opinion will have been consistent with my behavior. The cognitive dissonance that was aroused because of the discrepancy between my attitude and my behavior would no longer exist.

Here, because of the subject’s past actions, their own stinginess is harder to dispute, and (a) is now also an implausible option. In effect, (b) now becomes the default choice, and the subject concludes they do not care so much about poor people.

The Meat Paradox

In the Western world, most ascribe some level of moral significance to the suffering of animals, as illustrated by (among other things) the existence of animal cruelty laws. On the other hand, the consumption of meat is ubiquitous, and it is also common knowledge that this leads to animal suffering. The tension between these has been called the “meat paradox” (Loughnan et al. 2010) and resolves as the following trilemma:

1) Stop/reduce consumption of animal products

2) Eliminate/lower concern for animal suffering

3) Compartmentalize/dissociate the two (e.g. “my diet won’t make a difference”)

A flurry of research in recent years has studied how this dissonance is resolved. While the exact numbers are hard to determine, it has been noted that moral disengagement strategies are quite common, while changing one’s diet for moral reasons is inconvenient and rare (Graca et al. 2014; Blidaru and Opre 2015:549).

Loughnan et al. (2010) tested if option (2) is also at play: subjects were randomly assigned to snack on either cashews or beef jerky, and later asked to indicate which of 27 animals they felt moral concern for, in a standard "moral circle task". Subjects in the jerky group cared about less animals, including cows specifically. That is, the mere act of having eaten meat caused them to more readily adopt speciesist attitudes. In a similar study, Bastian et al. (2012) found that, compared to a control group to be given apples, subjects who were led to expect to eat meat later had diminished ratings of the mental capacities of the animal they expected to eat.

Moreover, Rothgerber (2014) found that, “participants who read a vignette about a vegetarian denied animal mind more than participants who read about a gluten-free individual”, indicating that simply thinking about vegetarians induces speciesist thoughts. Furthermore, this effect was more pronounced when the subject was read a paragraph of an authentic vegetarian vs. an imposter; a vegetarian freely making the decision to abandon meat vs. due to allergies; as well a morally consistent vegetarian vs. a vegetarian who wears fur.

Forcing the Choice

We observe that option (3) becomes less feasible in any circumstance that makes the connection between an individual’s diet and animal suffering more salient. In such cases, we have shown that (2) is the preferred defense mechanism in some cases; that is, speciesist attitudes will be adopted reflexively to justify past, present, and future behavior. Moreover, it is also clear that others simply pick (1) and change their diet in response, or at least think more about animal suffering without changing their behavior.

An important question to ask for vegan advocacy, then, is how the typical person resolves their dissonance in such situations. The rate at which people intensify latent anti-speciesist attitudes and choose (1) should be compared against the rate at which speciesist attitudes are defensively adopted in line with (2).

Here, alas, the psychological literature runs dry. However, we do have the following observations by Oscar Horta (2016), a moral philosopher and experienced animal advocate in Spain:

When Horta presented high school students with arguments against speciesism, most accepted the idea that animal suffering deserved moral consideration. When he later discussed veganism, the idea wasn’t met with a negative reaction and there was an interesting discussion about it.
For students in other classes, Horta first discussed veganism, and received a cold reception. Later, when he gave the same arguments against speciesism, fewer students were convinced than before, since many seemed to rationalize their rejection of veganism.

I was curious about this, since this seemed to imply two non-trivial claims:

a) Most who heard the arguments against speciesism found them convincing

b) When veganism is presented first, acceptance of the same arguments against speciesism is smaller

When I emailed Horta about this, he stated that he is

quite convinced about [(a) and (b), above] after getting similar responses quite consistently, I'm not really in a position to convince others about this, unfortunately, as I can't back this by presenting a full, well planned, study about this.

That said, it should be noted that:

  • These are merely anecdotal observations of Spanish high schoolers, so perhaps even less likely to generalize than studies in social psychology
  • Horta was already on the "antispeciesism" side of the debate in animal advocacy of whether to focus on veg*nism or general antispeciesism, so he's perhaps not an unbiased source

Appendix: Other Notes on the Psychology of Veg*nism

Minson and Monin (2012) looked at the anticipated moral reproach omnivores have of vegetarians. In rating how moral they were on a 7-point scale, they rated vegetarians to be more moral than omnivores. Though statistically significant, this gap was 1/9 the size of the gap that omnivore subjects anticipated that vegetarians would expected gulf vegetarians would assign. In particular, participants rated their own morality highly, but expected vegetarians to rate them poorly. Subsequently, the omnivore participants were asked to associate vegetarians with words or phrases of positive or negative valence. Using this metric, there was a negative correlation between the valence of the subject’s attitude towards vegetarians, and how morally superior they expected vegetarians to be to omnivores, and the subject themself.

In the next phase, subjects were assigned to two groups: the "Threat First" group was asked to consider how vegetarians would view them, before rating vegetarians themselves. In the "Rating First" group these tasks were reversed. As predicted, Threat First subjects rated vegetarians more negatively, having just anticipated moral reproach (the effect size was small, but a similar result was found in Study 5 of Rothgerber (2014)). More surprisingly, when both groups were assessed on pro-meat attitudes afterwards, there was a marginal effect (i.e. significant at the .1 but not .05 level) of the Rating First group being more pro-meat, despite its (comparatively) higher opinion of vegetarians. The authors hypothesized that, since they had just experienced the moral threat, they felt a temporary need to express their pro-meat attitudes. Indeed, on a follow-up, subjects with no threat manipulation had attitudes matching the Threat First group, indicating that, having defused the threat by putting down vegetarians in their ratings, their attitudes returned to baseline. In Minson and Monin’s words, “having shot the messenger, participants may have felt less urge to also burn the message.”

Piazza and Loughnan (2016) analyze the paradox of why Westerners eat pork without a second thought but find dog meat unacceptable, even though the current evidence indicates pigs are probably smarter than dogs. In their first study, when abstractly considering the moral standing of animals, subjects are found to consider intelligence a factor. In study 2, manipulating the intelligence of a fictional animal is found to affect their perception of its moral standing. This effect is also seen in the case of tapirs, but not pigs. In study 3, subjects predicted that learning about pig intelligence would raise their perceived moral standing, but their own judgments are unaffected when they themselves are so informed.

It is also worth asking how the perceptions described above generalize to other countries. Ruby et al. (2016) note the paucity of research of attitudes towards meat and vegetarians in non-Western countries. However, looking at the US, France, Argentina, and Brazil, countries chosen for their high per capita consumption of beef, subjects in the US were the most openly bothered by vegetarians. On a scale of -3 (“disagree strongly”) to 3 (“agree strongly”) of “vegetarians bother me”, we had the US at -1.18, France -1.67, Brazil -1.6, Argentina -2.07.

Social identity theory may have many more insights into the psychology of speciesism not explored here (Dhont and Hodson 2014), but these are likely to be country-specific: in India, for instance, vegetarianism is associated with conservative cultural values, in contrast to the US (Ruby et al. 2013).


Animal Classroom (2016). (Óscar Horta) Talks in secondary schools about speciesism, ethics and animals. https://translate.google.com/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Faulaanimal.com%2F%3Fp%3D3328&edit-text=&act=url (original Spanish from http://aulaanimal.com/?p=3328)

Bastian, B., Loughnan, S., Haslam, N., & Radke, H. (2012). Don’t mind meat? The denial of mind to animals used for human consumption. Personality and Social Psychology Bulletin, 38, 247–256. https://www.academia.edu/12268550/Don_t_mind_meat_The_denial_of_mind_to_animals_used_for_human_consumption

Blidaru, Ligia; Opre, Adrian (2015). The Moralization of Eating Behavior. Gendered Cognitive and Behavioral Strategies. Procedia - Social and Behavioral Sciences. 187: 547–552. https://www.sciencedirect.com/science/article/pii/S1877042815018959

Cooper, J. (2007). Cognitive dissonance: 50 years of a classic theory. Sage.

Dhont, K., & Hodson, G. (2014). Why do right-wing adherents engage in more animal exploitation and meat consumption?. Personality and Individual Differences, 64, 12-17. https://biblio.ugent.be/publication/5030419/file/5030437

Festinger, L. (1957). A Theory of cognitive dissonance. Evanston, IL: Row, Peterson.

Graça, João; Calheiros, Maria Manuela; Oliveira, Abílio (Oct 2014). Moral Disengagement in Harmful but Cherished Food Practices? An Exploration into the Case of Meat. Journal of Agricultural and Environmental Ethics. 27 (5): 749–765. https://link.springer.com/article/10.1007/s10806-014-9488-9

Horta, O. (2016). Talks in secondary schools about speciesism, ethics and animals. Aula Animal. https://translate.google.com/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Faulaanimal.com%2F%3Fp%3D3328&edit-text=&act=url (original Spanish from http://aulaanimal.com/?p=3328)

Loughnan, S.; Bastian, B.; Haslam, N. (2014). The Psychology of Eating Animals. Current Directions in Psychological Science. 23 (2): 104–108. https://foodethics.univie.ac.at/fileadmin/user_upload/inst_ethik_wiss_dialog/Loughnan__S._2014_And_Bastian._..The_Psychology_of_Eating_Animals._In._CURRENT_DIRECTIONS_IN_PSYCHOLOGICAL_SCIENCE.pdf

Loughnan, S., Haslam, N., & Bastian, B. (2010). The role of meat consumption in the denial of mind and moral status to meat animals. Appetite, 55, 156–159. https://www.researchgate.net/publication/44616810_The_role_of_meat_consumption_in_the_denial_of_moral_status_and_mind_to_meat_animals

Minson, J. A., & Monin, B. (2012). Do-gooder derogation: Disparaging morally motivated minorities to defuse anticipated reproach. Social Psychological and Personality Science, 3(2), 200-207. https://faculty.wharton.upenn.edu/wp-content/uploads/2011/12/Minson---Monin,-2011.pdf

Piazza, J., & Loughnan, S. (2016). When Meat Gets Personal, Animals’ Minds Matter Less: Motivated Use of Intelligence Information in Judgments of Moral Standing. Social Psychological and Personality Science, 7(8), 867-874. http://journals.sagepub.com/doi/pdf/10.1177/1948550616660159

Rothgerber, H. (2014). Efforts to overcome vegetarian-induced dissonance among meat eaters. Appetite, 79, 32-41. https://ac.els-cdn.com/S0195666314001688/1-s2.0-S0195666314001688-main.pdf?_tid=14a8f9f6-f41f-11e7-8d46-00000aab0f01&acdnat=1515380179_ca8eed50c3cd6a35616e4f1a03836c8f

Ruby, M. B., Heine, S. J., Kamble, S., Cheng, T. K., & Waddar, M. (2013). Compassion and contamination. Cultural differences in vegetarianism. Appetite, 71, 340-348. http://www.sciencedirect.com/science/article/pii/S0195666313003863

Ruby, M. B., Alvarenga, M. S., Rozin, P., Kirby, T. A., Richer, E., & Rutsztein, G. (2016). Attitudes toward beef and vegetarians in Argentina, Brazil, France, and the USA. Appetite, 96, 546-554. https://web.sas.upenn.edu/rozin/files/2016/09/Rubyetal.2016.4CountriesBeefVeg-26fbtxl.pdf

Vaidis, D. C., & Bran, A. (2019). Respectable Challenges to Respectable Theory: Cognitive Dissonance Theory Requires Conceptualization Clarification and Operational Tools. Frontiers in psychology, 10. https://www.frontiersin.org/articles/10.3389/fpsyg.2019.01189/full

Zukier, H. (1989). "Introduction." In Schachter, S., & Gazzaniga, M. S. (Eds.), Extending Psychological Frontiers: Selected Works of Leon Festinger (pp. xi–xxiv). New York, NY: Russell Sage Foundation. https://www.russellsage.org/sites/all/files/schachter_intro.pdf

Note: This was written up in 2017, as the core of a paper that also included more speculative conclusions. After helpful comments from Jacy Reese, Jesse Clifton, Brian Tomasik, and Georgia Ray, I half-disavowed those speculations and didn't feel like posting it anywhere else. On reviewing it recently, I've decided to leave this lit review here so its publicly viewable/searchable as a reference (I've also reconsidered/reformulated my old speculations into a separate post about moral circles to be published shortly). I also learned of some relevant literature I missed in this review: 1, 2, 3.

Sorted by Click to highlight new comments since:

I would have appreciated if your summary had also included a line or two on what your main conclusions were.

I think an important piece of the puzzle that I didn't see mentioned here is that most people, most of the time resolve their cognitive dissonance towards eating animals by not experiencing it. We put slaughterhouses in the countryside, remove any heads or hooves or skin from our butchers, hang out with friends who do the same, and often make it illegal to film how animals are treated.

Bastian and Loughnan talk about this as passive dissonance avoidance in "resolving the meat paradox" which is a summary of the literature you can read here: https://static1.squarespace.com/static/57d2f8668419c276f91f3b04/t/5846ac15579fb36bace325ee/1481026582391/resolving-the-meat-paradox.pdf

To anyone interested in this topic, the other great review (in my opinion) is "Toward a Psychology of Human-Animal Relations" https://static1.squarespace.com/static/57d2f8668419c276f91f3b04/t/5846af5f9f74567368763722/1481027424005/toward-a-psychology-of-human-animal-relations.pdf

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