Humans first: Why people value animals less than humans

L. Caviola, S. Schubert, G. Kahane, & N. S.Faber

Cognition

Volume 225, August 2022, 105139

Abstract

People routinely give humans moral priority over other animals. Is such moral anthropocentrism based in perceived differences in mental capacity between humans and non-humans or merely because humans favor other members of their own species? We investigated this question in six studies (N = 2217). We found that most participants prioritized humans over animals even when the animals were described as having equal or more advanced mental capacities than the humans. This applied to both mental capacity at the level of specific individuals (Studies 1a-b) and at the level typical for the respective species (Study 2). The key driver behind moral anthropocentrism was thus mere species-membership (speciesism). However, all else equal, participants still gave more moral weight to individuals with higher mental capacities (individual mental capacity principle), suggesting that the belief that humans have higher mental capacities than animals is part of the reason that they give humans moral priority. Notably, participants found mental capacity more important for animals than for humans—a tendency which can itself be regarded as speciesist. We also explored possible sub-factors driving speciesism. We found that many participants judged that all individuals (not only humans) should prioritize members of their own species over members of other species (species-relativism; Studies 3a-b). However, some participants also exhibited a tendency to see humans as having superior value in an absolute sense (pro-human species-absolutism, Studies 3–4). Overall, our work demonstrates that speciesism plays a central role in explaining moral anthropocentrism and may be itself divided into multiple sub-factors.

From the General Discussion

The distal sources of moral anthropocentrism

So far, we have discussed how the factors of moral anthropocentrism are related to each other. We now turn to briefly discuss what ultimate factors may explain moral anthropocentrism, though at present there is little evidence that directly bears on this question. However, evolutionary considerations suggest a preliminary, even if inevitably speculative, account of the ultimate sources of moral anthropocentrism. Such an explanation could also shed light on the role of the sub-factors of speciesism.

There is extensive evidence that people categorize individuals into different groups (cf. Tajfel, Billig, Bundy, & Flament, 1971), identify with their own group (Hornsey, 2008; Tajfel & Turner, 1979), and prioritize members of their ingroup over members of their outgroup (Balliet, Wu, & De Dreu, 2014; Crimston et al., 2016; Fu et al., 2012; Sherif, 1961; Yamagishi & Kiyonari, 2000; for bounded generalized reciprocity theory, cf. Yamagishi & Mifune, 2008). Ingroup favoritism is expressed in many different contexts. People have, for example, a tendency to favor others who share their ethnicity, nationality, religion, or political affiliation. (Rand et al., 2009; Whitt & Wilson, 2007). It has been argued that ingroup favoritism is an innate tendency since it can promote safety and help to encourage mutual cooperation among ingroup members (Gaertner & Insko, 2000). It seems, therefore, that there are good reasons to assume that speciesism is a form of ingroup favoritism analogous to ingroup favoritism among human groups.

While typical human ingroups would be far smaller than humanity itself, our similarity to other humans would be salient in contexts where a choice needs to be made between a human and a non-human. Since the differences between humans and animals are perceived as vast—in terms of biology, physical appearance, mental capacities, and behavior—and the boundaries between the groups so wide and clear, one would expect ingroup favoritism between humans and animals to be particularly strong. Indeed, research suggests that perceived similarity with outgroup members can reduce ingroup favoritism—as long as they are seen as non-threatening (Henderson-King, Henderson-King, Zhermer, Posokhova, & Chiker, 1997). Similarly, it has been shown that people have more positive reactions towards animals that are perceived as biologically, physically, mentally, or behaviorally more similar to humans than animals that are dissimilar (Burghardt & Herzog, 1989; Kellert & Berry, 1980).

The research is here.

Children Prioritize Humans Over Animals Less Than Adults Do

Wilks M, Caviola L, Kahane G, Bloom P.

Psychological Science. 2021;32(1):27-38. 

doi:10.1177/0956797620960398

Abstract

Is the tendency to morally prioritize humans over animals weaker in children than adults? In two preregistered studies (total N = 622), 5- to 9-year-old children and adults were presented with moral dilemmas pitting varying numbers of humans against varying numbers of either dogs or pigs and were asked who should be saved. In both studies, children had a weaker tendency than adults to prioritize humans over animals. They often chose to save multiple dogs over one human, and many valued the life of a dog as much as the life of a human. Although they valued pigs less, the majority still prioritized 10 pigs over one human. By contrast, almost all adults chose to save one human over even 100 dogs or pigs. Our findings suggest that the common view that humans are far more morally important than animals appears late in development and is likely socially acquired.

From the Discussion section

What are the origins of this tendency? One possibility is that it is an unlearned preference. For much of human history, animals played a central role in human life—whether as a threat or as a resource. It therefore seems possible that humans would develop distinctive psychological mechanisms for thinking about animals. Even if there are no specific cognitive adaptations for thinking about animals, it is hardly surprising that humans prefer humans over animals—similar to their preference for tribe members over strangers. Similarly, given that in-group favoritism in human groups (e.g., racism, sexism, minimal groups) tends to emerge as early as preschool years (Buttelmann & Böhm, 2014), one would expect that a basic tendency to prioritize humans over animals also emerges early.

But we would suggest that the much stronger tendency to prioritize humans over animals in adults has a different source that, given the lack of correlation between age and speciesism in children, emerges late in development. Adolescents may learn and internalize the socially held speciesist notion—or ideology—that humans are morally special and deserve full moral status, whereas animals do not. 

A pdf of the research is here.