Temple Grandin is widely known as an advocate for animal welfare. She is also a slaughterhouse designer and meat eater. She has spent much of her professional life promoting humane practices for livestock farms and slaughtering plants, and has been recognized by People for the Ethical Treatment of Animals for her tireless efforts. She has also written in defense of meat as a food, and is embraced as an ally by the meat industry. A couple years ago, she even defended the beef industry’s controversial marketing of pink slime.

Grandin has no trouble reconciling these views and activities. But she does have to reconcile them, as we all do. The average American consumes more than 250 pounds of meat a year, an appetite fed by the slaughter of 10 billion animals. Yet we spend a fortune on our pets, too. The fact is that we both care for animals and eat them. How do we manage the psychological tension created by these seemingly conflicting values?

Psychological scientist Steve Loughnan of the University of Melbourne calls this the “meat paradox.” He and his colleagues have been working for years to understand the psychological gymnastics we use to resolve and live with this moral dilemma. They summarize this research, and that of others, in an article to appear in the journal Current Directions in Psychological Science.

The surest and most obvious way to eliminate this moral and psychological tension is to abstain from meat—to become vegan or vegetarian. Many vegans say that they are disgusted by the idea of eating meat, and disgust is a powerful emotion. But very few of us ever take this step. That’s because—well, because meat tastes good. The interplay of pleasure and disgust determines whether we abstain or indulge in hamburgers and barbecued chicken.

Loughnan and colleagues wanted to know why pleasure trumps disgust for some of us, and the other way around for others. To find out, they have been studying carnivores themselves: What are their attitudes and values in general, and how do they perceive cattle and Labrador retrievers and other creatures? How do they tip the balance toward pleasure and away from disgust?

They’ve found some intriguing and consistent differences between meat eaters and vegetarians. For example, meat eaters tend to be more authoritarian in general, believing that it is acceptable to be aggressive and controlling with subordinates. Meat eaters are also more likely to accept inequality and to embrace social hierarchies. Apparently these attitudes—toward other humans—make meat eating less morally problematic. Interestingly, omnivores who value inequality and hierarchy also eat more red meat than do their less dominant peers. Meat eating is also closely linked to male identity—indeed, so closely that meat is often seen as metaphorically male. Apparently, real men really don’t eat quiche—at least broccoli quiche—or anything else that doesn’t come off a bone.

These personal values are also reflected in meat eaters’ beliefs about the eaten—perceptions of animals’ minds and their similarities to us. To be worthy of moral concern, a steer or tabby must be sensitive to pain and suffering. So simply put, we all ask ourselves, do animals suffer? But we answer that question in various ways. In recent studies, Loughnan and others have asked people to rate the extent to which 32 animals possessed mental capacities—and their willingness to eat each animal. They found that eating a “mindful” animal was seen as more morally wrong and as more unpleasant. Across cultures, respondents were more disgusted by the prospect of eating a thinking animal—a pet dog, for instance—than a hog.

People are biased by animals’ human-like traits. In one study, for example, people judged more human-like animals as more sensitive to pain. And they didn’t just report this view; they became more aroused physically when they saw these animals being mistreated. The opposite is also true: People who see animals as unlike humans also see them as more mindless and less worthy of concern. These perceptions provide a powerful cognitive tool for resolving the meat paradox. Notably, people may see animals as capable of suffering, but not when humanely killed. That seems to be the point of view of many omnivores, including Temple Grandin.

So there’s the eater and the eaten—and there’s also the very act of eating itself. If all carnivores must reconcile competing values in general, then this precise moment of eating meat—cow on fork–requires the most urgent kind of psychological resolution. That’s what Loughnan and his colleagues believe, so in one of their studies, they asked volunteers to eat either beef or nuts. They then described their moral concern for animals in general, and their estimate of a cow’s capacity for suffering. Those who had recently eaten beef—and only those—saw the cow as less capable of suffering. They also saw animals in general as less deserving of concern. The scientists got the same result when volunteers were merely anticipating the act of eating beef or nuts. In short, people seem to alleviate unpleasant feelings about eating meat by diminishing the minds of animals.

Readers will recognize these findings as consistent with the theory of cognitive dissonance. When behavior is a poor match with beliefs and values, something’s got to give. Vegetarians change their behavior. But the rest of us—nine out of ten—ease the discomfort by altering our beliefs—about animals’ minds, suffering, and moral standing.

Follow Wray Herbert’s reporting on psychological science in The Huffington Post and on Twitter at @wrayherbert.