It is more permissible to harm a few animals to save a greater number of animals than to harm a few humans to save a greater number of humans, even when animals are described as having greater suffering capacity than some humans

Caviola, L., Kahane, G., Everett, J. A. C., Teperman, E., Savulescu, J., & Faber, N. S. (2021). Utilitarianism for animals, Kantianism for people? Harming animals and humans for the greater good. Journal of Experimental Psychology: General, 150(5), 1008–1039. Jun 2021. https://doi.org/10.1037/xge0000988

Abstract: Most people hold that it is wrong to sacrifice some humans to save a greater number of humans. Do people also think that it is wrong to sacrifice some animals to save a greater number of animals, or do they answer such questions about harm to animals by engaging in a utilitarian cost-benefit calculation? Across 10 studies (N = 4,662), using hypothetical and real-life sacrificial moral dilemmas, we found that participants considered it more permissible to harm a few animals to save a greater number of animals than to harm a few humans to save a greater number of humans. This was explained by a reduced general aversion to harm animals compared with humans, which was partly driven by participants perceiving animals to suffer less and to have lower cognitive capacity than humans. However, the effect persisted even in cases where animals were described as having greater suffering capacity and greater cognitive capacity than some humans, and even when participants felt more socially connected to animals than to humans. The reduced aversion to harming animals was thus also partly due to speciesism—the tendency to ascribe lower moral value to animals due to their species-membership alone. In sum, our studies show that deontological constraints against instrumental harm are not absolute but get weaker the less people morally value the respective entity. These constraints are strongest for humans, followed by dogs, chimpanzees, pigs, and finally inanimate objects.