Meat Disgust: An Evolutionary Echo?

Humans reject certain foods for a variety of reasons. Sometimes it’s a matter of unappealing appearance or odour. Other times, the very idea of consuming a particular food can be revolting. While the terms ‘distaste’ and ‘disgust’ are often used interchangeably, they represent distinct psychological processes. Recent research has delved into whether these emotional reactions differ depending on whether the rejected food originates from a plant or an animal. The findings lend weight to the evolutionary theory that humans developed disgust as a specific defence mechanism against pathogens commonly found in meat.

The study, published in a scientific journal, sought to understand the ‘how’ and ‘why’ behind the rejection of commonly eaten foods. Previous investigations have suggested that animal-derived foods are more likely to trigger disgust, whereas plant-based foods are typically rejected due to their taste. This difference may have evolutionary roots: taste might have helped early humans avoid bitter plant toxins, while disgust could have evolved as a defence against pathogens lurking in meat. A deeper understanding of these emotional reactions could inform interventions aimed at promoting healthier and more sustainable dietary choices.

According to Elisa Becker, a postdoctoral researcher at the University of Oxford, an earlier study revealed that a significant proportion of vegetarians, along with some flexitarians and even omnivores, expressed aversion to meat. This observation prompted her to question whether taste alone was responsible, or if deeper psychological processes were at play. This line of inquiry led to an investigation into whether meat elicits the same kind of disgust that we feel towards truly repulsive substances like faeces or human flesh.

Methodology: Online Surveys and Food Images

To explore this hypothesis, the researchers conducted two online surveys involving a total of 309 participants from the United Kingdom. The main group comprised 252 individuals who had previously indicated an aversion to meat – the majority of whom were vegetarians. A smaller control group of 57 meat-eating participants served as a comparison, providing a baseline for disgust reactions. All participants were asked to rate a series of food images based on various psychological and emotional criteria. These included their willingness to eat the food, their perception of its taste and appearance, and whether it triggered thoughts of contamination, death, or moral offence.

The participants were presented with images of different types of food, divided into four categories:

• Palatable but commonly disliked vegetables: Examples included Brussels sprouts and olives.
• Culturally acceptable meat: Such as chicken, beef, and pork.
• Classic disgust-inducing substances: Including dog meat and faeces.
• Neutral control food: Bread.

Participants rated 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: Feelings of nausea, for example.
• Animal-reminder disgust: Reminders of death or animal parts.
• Moral disgust: Offence at the idea of eating the food.

Analysis of Rejection Profiles

Only participants who indicated an unwillingness 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 analysing the response patterns across various questions, they created “rejection profiles” for each food and used statistical techniques to examine the similarities and differences between these profiles.

Key Findings: Meat Rejection and Disgust

The results revealed a clear distinction in how participants responded to meat versus vegetables. When people rejected meat, their reactions closely resembled those of the control group when presented with images of dog meat and human faeces.

The researchers noted the striking similarity between responses to meat and classic disgust triggers like faeces and human meat. They had anticipated some overlap, but the response profiles were almost indistinguishable.

These meat rejection responses were characterised by high ratings on measures related to disgust, particularly ideational contamination (the belief that even a small amount of the food could contaminate an entire dish) and incorporation (the thought of the food being inside the body). In contrast, rejected vegetables were primarily rated negatively for their taste, with relatively low ratings on disgust-related dimensions.

Visualising Emotional Distance

A statistical method known as multidimensional scaling confirmed these patterns. This technique allowed the researchers to visually represent the emotional distance between different food responses on a two-dimensional map. Rejected meats and prototypical disgust elicitors like faeces clustered closely 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.

Subtypes of Disgust

Further investigation into the subtypes of disgust experienced when meat was rejected revealed that core disgust – responses related to nausea and the thought of the food being in the mouth – was the predominant reaction across all meat stimuli. Moral disgust (finding the act of eating meat offensive) and animal-reminder disgust (being reminded of body parts or death) were also present, but less strongly endorsed. This pattern mirrored reactions to dog meat and human flesh, suggesting that meat rejection among vegetarians shares emotional qualities with some of the most deeply ingrained food taboos.

The study highlights that when someone is “put off” by meat, it triggers a gut-level disgust response akin to that elicited by the most revolting substances imaginable. Disliked vegetables, on the other hand, do not trigger this response; they are rejected purely based on their taste or texture. This helps to explain why some individuals hold such strong negative feelings towards meat.

Qualitative Responses: Contamination and Moral Harm

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

Limitations and Future Research

While the study design provided compelling evidence for distinct rejection mechanisms, it did have limitations. The researchers relied on self-report measures, which can be influenced by how people interpret and respond to survey questions. The meat-rejecting group consisted primarily of vegetarians, and the sample was predominantly female, which could impact the generalisability of the findings. Furthermore, as the study focused on subjective ratings rather than physiological or behavioural data, future research employing other methods could help to validate the results.

Despite these limitations, the study underscores a significant distinction in how people relate to different types of food. By demonstrating that disgust, and not just dislike, drives many meat rejections, the researchers suggest that disgust may have initially evolved as a specialised defence against contaminated meat. Over time, this reaction may have become more generalised, serving as a psychological alarm system for anything that poses a pathogen threat.

Future research aims to better understand how these food-related emotions develop over time. Disgust doesn’t typically emerge in children until around the age of 3-5, by which time most are already consuming meat. Therefore, understanding when and how meat disgust begins is crucial for supporting healthier and more sustainable dietary patterns.

The significance of this research lies in the understanding that disgust functions as a psychological alarm system that evolved to protect us from illness, parasites, and pathogens – health threats particularly associated with meat. It is therefore logical that humans can respond with disgust to anything that could be contaminated, such as faeces, but also to various types of meat. Disgust towards vegetables is less readily explained, and the study provides support for this evolutionary perspective.