A series of studies validate a new measure of speciesism, and show how it relates to other prejudices, empathy, open-mindedness, and pro-animal behavior.

Speciesism is a word that is probably familiar to animal advocates. Like the related concepts of racism or sexism, it describes a way of behaving toward a particular group—in this case, members of other species.

What does speciesism look like? You’ll see it in the near-universal belief that humans are worth more than members of other species. You’ll see it in the way that species of similar intelligence and emotional capacity—like pigs and dogs—are treated completely differently (love one, eat the other). And you’ll see it in the fact that outside of animal advocacy circles, the term speciesism is one that many people haven’t encountered before.

This article accomplishes two significant goals. First, it describes the process the researchers went through to create and validate a measure of speciesism, which can now be used by animal advocates as a trustworthy measure of this concept. And second, in the authors’ own words, it “introduce[s] and investigate[s] the philosophical concept of ‘speciesism’ … as a psychological construct.”

Although the focus of this summary is on the scale validation, the second point is major and should not be overlooked. The article is published in the Journal of Personality and Social Psychology, the most influential publication in those two fields. Thus, it introduces a central concept of animal advocacy to mainstream academic psychologists, opening it up to thought and study by experts in the active field of intergroup relations and prejudice.

This article provides evidence for several important points: that speciesism is something measurable, that it varies from person to person, and that it matters.

First, the researchers went through a rigorous scale development process. Beginning with 27 potential items, they used a statistical technique called factor analysis to narrow them down, retaining only non-redundant items and items that are purely representative of speciesism, rather than related concepts like ethical vegetarianism.

Using the final scale, women and vegetarians tended to be less speciesist than men and non-vegetarians, but there were no significant differences in speciesism for people of different ages, education, or income levels. A test-retest study showed that individuals’ scores on the final measure were consistent over a four-week period. Thus, as predicted, this study showed that individuals differ in how speciesist they are, and individual levels of speciesism don’t change quickly over time, just like sexism or racism.

The final version of the scale is provided below, with permission from first author Lucius Caviola.

Having shown that speciesism can be measured in individuals in a valid and reliable way, the researchers investigated how it relates to ways of thinking. They found significant, sizeable correlations between speciesism and three other major forms of prejudice: sexism, racism, and homophobia. That is, they found that people who are prejudiced toward humans who are different from themselves also tend to be prejudiced toward other species. Other analyses indicated that people high on speciesism tended to be less empathic toward other people and less open-minded in their thinking.

Finally, the researchers looked at whether speciesist attitudes have an observable effect on behavior. People who scored high on the speciesism scale were the most likely to show a donation bias toward a charity benefitting humans rather than animals, and a charity benefitting dogs rather than pigs. Those who scored high were also more likely to choose to spend time assisting a non-profit organization that benefits homeless people than one for chimpanzees.

In the final check, at the end of the time-investment study, participants were offered their choice of snack as a reward. People who scored high on speciesism were more likely than those who scored low to choose a meat snack over a non-meat snack. Speciesism significantly predicted all of these behaviors even when several key demographic and psychological factors were controlled.

In sum, the results of this study support speciesism as a measurable, impactful phenomenon. The researchers developed and validated a strong measure of speciesism that can be used with confidence by animal advocates. Between the development of this new scale and the introduction of speciesism to academic psychologists, this article has the potential for substantial impact on animal advocacy research.