In many ways, human history shows us that differences among people often result in prejudice, and prevailing beliefs that some are inherently inferior to others. This is also true for non-human animals. While most people today view beliefs such as racism and antisemitism as condemnable, the same is not true regarding speciesism. In the last few decades, researchers have proposed that the link between the devaluation of human groups and non-human animals can be explained by the same psychological mechanism. This means that individuals that tend to devalue other human groups (e.g., racism, sexism, antisemitism) also tend to devalue non-human animals (speciesism). This form of prejudice, which is defined as a “devaluating sentiment towards a specific group,” is referred to as a generalized prejudice because it extends above one specific group and becomes a pattern applied more broadly.

While this correlation was already known, previous studies were mainly done in English-speaking countries, and most of the population included in these studies were university students — not representative of the general population. The current paper includes two studies: one that broadens the scope of this correlation to more than 56,000 respondents from 46 European countries, and a second one that further looks into attitudes, beliefs, emotional responses, and behaviors related to meat consumption in a smaller cohort of 1,500 Dutch participants. To do so, the author used the results of multiple surveys. 

In the first study, they used the European Values Survey from 2008. This survey is administered every 9 years all over Europe to “understand trends in value, attitudes, beliefs, and other indicators.” Prejudice against non-human animals was measured with a single item: participants were asked to note their agreement with the statement “Humans were meant to rule over nature.” Prejudice against human groups was measured using three items: a prejudice measure against other human races, a prejudice measure against marginalized groups and a prejudice measure against all groups (including groups that are not marginalized). Several socio-demographic variables were recorded (sex, age, level of education, income, religiosity, and political orientation).

In the second study, they used multiple surveys from the LISS (Longitudinal Internet Studies of the Social Science) from 2012, a dataset of surveys from a population representative of Dutch households. Specifically, one survey on attitudes towards animals and meat consumption served as the main data source, and other surveys on prejudice and political orientation were used to measure correlations. These surveys explored general attitude towards meat consumption (moral acceptance), emotional responses towards the use of animals in food production (discomfort, shame, and guilt), and behaviors (self-described diet, frequency and quantity of meat consumption, source of meat from an “ethical producer,” and willingness to eat meat substitutes). Prejudice towards human groups was measured from five questions about immigrants and people of foreign descent in the Netherlands. Socio-demographic data were also recorded (gender, age, education, income, urban vs. rural environment).

The first study examined human supremacy beliefs and showed a strong correlation between prejudice against human groups (even including those that are not typically marginalized) and against non-human animals. This correlation was still present when controlling for socio-demographic characteristics. This means that the human supremacy belief is not specifically linked to gender, education levels, or political orientations, but is mostly shared by individuals who also share human-directed prejudice.

The second study further supported this conclusion. Dutch individuals who showed higher scores of prejudice against immigrants and people of foreign descent (groups that are typically marginalized) were positively correlated to many variables related to human supremacy over non-human animals. They reported:

• more positive attitudes towards meat production*
• stronger beliefs that meat production is animal-friendly 
• stronger beliefs that meat production is morally acceptable
• less feelings of discomfort*
• less feelings of shame*
• less feelings of guilt
• more likelihood to identify as meat-eaters*
• eating meat more often*
• eating meat in greater quantities*
• less likelihood to buy “ethically produced” meat*
• less willingness to buy meat substitutes*

*When controlling for socio-demographic characteristics, these eight out of eleven associations were still positively correlated. This means that they are commonly shared. Variables that are not correlated to human-directed prejudice anymore when controlled for socio-demographic characteristics mean that they can be correlated to some of these characteristics, such as gender, age, or political values, rather than to prejudice.

While this study is valuable because it confirms the generalized prejudice towards humans and non-human animals, there are some limitations. First, surveys were limited to European countries. More work is needed to test this hypothesis in populations of non-Western backgrounds. Second, these surveys were not evaluating speciesism in itself, but rather measured various beliefs towards animal welfare and interests in the meat industry. While there was sufficient overlap between the two to see these measures as relevant, it would be of interest to capture speciesism more broadly. 

We can also see that, due to the limited extent of the surveys, very few variables were analyzed. It is possible that other variables, not controlled here, would explain the link between different forms of prejudice. However, finding what predictors could explain the link between prejudices was not the goal of this research. This study tested the descriptive (non-causal) claim that “people who are more prejudiced against humans also tend to show increased prejudice against animals.” It has now been shown to be true in a large and representative cohort of the European population. Finally, it’s also worth noting that these surveys were from 2008 and 2012; we may expect different results with more recent data. 

The study suggests one practical aim for advocates: the fact that generalized prejudice could be explained by one psychological mechanism implies that interventions aimed to reduce one prejudice could also succeed in reducing the others. This claim supports the idea that any form of discrimination should be frowned upon, whether it be about ethnicity, gender, sexuality, or species, as they usually work hand-in-hand.