Arguments about animal intelligence are not necessarily going to be successful in dissuading people from eating the animals they already consider to be “food.”

Morality can often be uncomfortable, and many people are much more willing to criticize the actions of others rather than change their own behavior. Many of the people vilifying Michael Vick’s involvement in dogfighting or calling for the end of the Yulin Dog Festival gladly eat meat and wear leather. What explains this discrepancy between beliefs and behavior?

In this study, researchers sought to find out, by conducting three different studies exploring the relationship between an animal’s perceived intelligence and participants’ views of their moral standing. They hypothesized that participants would be more willing to consider intelligence as morally significant with animals that they did not already consider to be “food.” Each study was conducted with different groups of participants, the first from the U.S. and the latter two from the U.K.

The first study created a fictional alien species called the “trablans,” that human explorers had found on another planet. One group of participants was told that the trablans were capable of tool use and complex problem-solving, while the other was told that they were incapable of even basic reasoning. Participants were asked to rate the trablans’ intelligence from 1-7. They were then told that some of the explorers were considering hunting, cooking, and eating the trablans, despite having brought enough food in their own supplies.

The participants were then asked five questions related to the moral standing of the animals, using the trablans as a stand-in, like “Is it morally okay to eat the trablans?” and “Would you eat the trablans yourself in the same instance?” Each question was answered on a scale from 1-7, and the average was taken to determine the individual’s attitude towards the trablans’ moral standing.

Finally, the participants were asked about their own dietary habits regarding meat. Unsurprisingly, the group told of the trablans’ tool use ranked them higher in intelligence than the low-intelligence group – 5.7 vs. 2.1. This was reflected in a lower opinion of the proposal to eat the trablans – 93% disapproved in the high-intelligence group, while 60% disapproved in the low-intelligence group. The low-intelligence group still did not think highly of the trablans’ moral status, with an average score of 3.7 vs the high-intelligence’s 5.7. Interestingly, diet did not have a major impact on participants’ views towards the aliens.

The second study split participants into three target groups, each with a secret “target animal” – pigs, tapirs (eaten in Asia and South America), and trablans. Each group was further split into a high-intelligence and low-intelligence group, the only difference between which was the comparison to dogs: the high-intelligence group was told the animal was smarter than dogs, while the low-intelligence group was told they were less intelligent. All participants were told that their target animal was originally hunted in the wild, but is now farmed for food. They were then asked to rate their own willingness to eat the animal and guilt about doing so. Additionally, they were told about abusive practices towards the other two animals and asked their willingness to eat them on the same scale. Intelligence did have an impact on participants’ willingness to eat all three animals, but less significantly with pigs than tapirs or trablans. In addition, participants were most willing to eat pigs at both intelligence levels.

Two groups were created for the final study, one which told participants that pigs were smarter than dogs, and one which said the opposite. Each of these groups was further split, with one asking the participants to answer from their own perspective, and one asking them to judge a hypothetical man named “John.” Both groups were asked to rank the intelligence of pigs from 1-7 and to answer “moral standing” questions related to either their own consumption of pigs or John’s hypothetical consumption. When told that pigs are more intelligent than dogs, participants were more judgmental of John eating pigs, but only marginally less likely to eat pigs themselves. In the low-intelligence groups, perspective did not matter.

It would appear that arguments about intelligence are not going to be successful in dissuading people from eating animals already considered to be “food.” However, such arguments might be more successful in cases where the animal is not typically eaten – for example, U.S. adults might be receptive to arguments about the intelligence of whales or octopi. The authors call for further research into whether people actively avoid learning information that may cause a moral dilemma, or if they just ignore it. By understanding which arguments are ineffective, animal advocacy groups can focus their resources in areas that will have the greatest impact, and it would appear that appeals about an animal’s intelligence are not high impact.