DATE: July 20, 2025 at 10:00AM
SOURCE: PSYPOST.ORG

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TITLE: Disgust toward meat may be a relic of our evolutionary past

URL: psypost.org/disgust-toward-mea…

Humans reject foods for different reasons. Sometimes it’s because a food looks or smells unpleasant. Other times, it’s because the idea of eating it seems revolting. These two reactions—distaste and disgust—are often confused in everyday language but reflect distinct psychological processes. In a new study, researchers explored whether these emotional reactions vary depending on whether the rejected food is a plant or an animal product. The findings provide support for an evolutionary theory that humans developed disgust specifically to avoid the pathogens often found in meat.

The study, published in Appetite, aimed to understand how and why people reject commonly eaten foods. Previous research suggested that animal foods are more likely to elicit disgust, while plant-based foods are typically rejected for their taste. This distinction could have evolutionary roots: taste may have helped humans avoid bitter plant toxins, while disgust may have evolved as a defense against pathogens in meat. By better understanding these emotional reactions, researchers hope to inform interventions that promote healthier and more sustainable diets.

“In an earlier study, we found that 74% of vegetarians (but also 15% of flexitarians and even a small share of omnivores) said they were put off by meat, which made me wonder: is this just about taste, or are deeper psychological processes at play? That led us to investigate whether meat is rejected with the same kind of disgust we feel toward truly revolting things like feces or human flesh,” said Elisa Becker, a postdoctoral researcher at University of Oxford, who conducted the study while at the University of Exeter.

To test their hypothesis, the researchers conducted two online surveys using a total sample of 309 participants from the United Kingdom. The primary group included 252 people who had previously shown an aversion to meat—most of whom were vegetarians. A smaller control group of 57 meat-eating participants served as a comparison and provided a baseline for disgust reactions. All participants rated a series of food images on multiple psychological and emotional criteria, including how willing they were to eat the food, how they felt about its taste and appearance, and whether it triggered thoughts of contamination, death, or moral offense.

The researchers showed participants images of different types of food across four categories: palatable but commonly disliked vegetables (such as Brussels sprouts and olives), culturally acceptable meat (chicken, beef, and pork), classic disgust-inducing substances (like dog meat and feces), and a neutral control food (bread). They asked participants to rate these foods across 12 dimensions. Five of these dimensions related to general taste and disgust criteria, while the remaining seven measured specific subtypes of disgust: core disgust (e.g., nausea), animal-reminder disgust (e.g., reminders of death), and moral disgust (e.g., offense at the idea of eating the food).

Only participants who indicated that they were unwilling to eat a particular food were included in the main analyses for that item. This allowed the researchers to directly compare the psychological profiles of rejected foods. By analyzing the response patterns across various questions, they created “rejection profiles” for each food and used several statistical techniques to examine how similar or different these profiles were from one another.

The results showed a clear divide in how participants responded to meat versus vegetables. When people rejected meat, their reactions were emotionally similar to how the control group responded to images of dog meat and human feces.

“The immense similarity between responses to meat and classic disgust items like feces and human meat was striking,” Becker told PsyPost. “We expected some overlap, but the response profiles were almost indistinguishable.”

These meat rejection responses were characterized by high ratings on measures related to disgust, especially ideational contamination (the idea that even a tiny amount could ruin a dish) and incorporation (the thought of the food being in the body). In contrast, rejected vegetables were mostly rated negatively for their taste, with relatively low ratings on disgust-related dimensions.

A statistical method called multidimensional scaling confirmed these patterns. This technique allowed the researchers to visualize the emotional distance between different food responses on a two-dimensional map. Rejected meats and prototypical disgust elicitors like feces clustered tightly together, while vegetables formed a separate cluster aligned with distaste. Bread appeared far from both groups, consistent with its role as a neutral control food.

To investigate further, the researchers looked into the subtypes of disgust experienced when meat was rejected. They found that core disgust—responses related to nausea and the thought of the food being in the mouth—was the dominant reaction across all meat stimuli. Moral disgust (e.g., finding the act of eating meat offensive) and animal-reminder disgust (e.g., being reminded of body parts or death) were present but less strongly endorsed. This pattern was also found in reactions to dog meat and human flesh, suggesting that meat rejection among vegetarians shares emotional qualities with some of the most deeply held food taboos.

“Our study shows that when someone is ‘put off’ by meat it triggers the same gut-level disgust as the most revolting substances we can imagine,” Becker explained. “Disliked vegetables on the other hand do not trigger this response – they were rejected purely because of their taste or texture. This helps explain why some people have very strong negative feelings about meat.”

The study also included an open-ended section where participants could describe any additional feelings about the foods. These qualitative responses aligned with the quantitative findings. People who rejected meat often used language associated with contamination, moral harm, or decay. Even when other types of disgust were mentioned, core disgust themes were nearly always present.

While the study design provided strong evidence for different rejection mechanisms, it did have some limitations. The researchers relied on self-report measures, which can be influenced by how people interpret and respond to survey questions. Most participants in the meat-rejecting group were vegetarians, and the sample was predominantly female, which could affect generalizability. Additionally, because the study focused on subjective ratings rather than physiological or behavioral data, future research using other methods could help validate the findings.

Despite these limitations, the study highlights a meaningful distinction in how people relate to different types of food. By showing that disgust, not just dislike, drives many meat rejections, the researchers argue that disgust may have originally evolved as a specialized defense against contaminated meat. Over time, this reaction may have become more generalized, serving as a psychological alarm system for anything that poses a pathogen threat.

Looking ahead, the researchers hope to better understand how these food-related emotions develop. “I’d like to understand how these emotional responses to food develop over time,” Becker said. “Disgust doesn’t start developing in children until they’re about 3-5 years old, by which time most already eat meat. So when and how does meat disgust start? These questions are important if we want to support healthier and more sustainable diets.”

“The really cool thing about this is that disgust is a psychological alarm system that evolved to protect us from getting sick, from getting in touch with parasites or pathogens. These are health threats found especially in meat. It makes sense then, that humans can respond with disgust to anything that could be contaminated – feces, for example, but also any kind of meat! It makes less sense to be disgusted by a vegetable, and we’ve found support for this theory.”

The study, “Disgust and distaste – Differential mechanisms for the rejection of plant- and animal-source foods,” was authored by Elisa Becker and Natalia S. Lawrence.

URL: psypost.org/disgust-toward-mea…

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