"I’m vegetarian." "I’m vegan." These statements typically will be met with a range of reactions, varying from bafflement to praise. But what makes people adopt a vegetarian or vegan diet? How are vegetarians and vegans viewed by the rest of society? And why don’t more people become vegetarian?

The ethics of eating

About 12% of the UK’s population is vegetarian or vegan. Many people adopt a vegetarian diet for health reasons, yet those that do appear to be less committed to their diet than those who reject meat for ethical reasons. So what is it about being ethically motivated that supports stronger commitments?

You often hear that people who shun meat for ethical reasons possess a greater capacity for empathy than those who don’t. Indeed, there is some evidence that ethically-motivated vegetarians and vegans score higher than omnivores on standard measures of empathy (for example, the empathy quotient).

Ethically-minded vegetarians and vegans also seem to have an expansive “circle of moral concern”, meaning that they think that many animals, including farm animals, deserve moral consideration and shouldn’t be harmed without good reason. A common attribute of meat eaters is that they tend to avoid thinking about the suffering of animals processed for meat. Because vegans and vegetarians place farm animals within their circle of moral concern, this causes them to take notice of their mental lives and suffering, and to scrutinise the justifications for eating meat.

Holier than thou?

It is not a secret that some people find vegetarians annoying. Ethically-motivated vegetarians and vegans in particular are often the target of ridicule and viewed as smug, self-righteous extremists. At the same time, many people acknowledge the ethical motivations of vegetarians and vegans, and give them credit for it. Why are these groups praised, yet also hated?

Ethically motivated people seem to serve as a source of anticipated reproach for most. People don’t like having their values or traditions criticised and respond defensively when they think they are under attack. It is not only vegetarians and vegans who are considered bothersome in this way. Any ethically motivated commitment, such as eating fair trade products, may be a source of anticipated reproach. The annoying ingredient seems to be the imagined criticism that the practice implies to those not practising it.

So why doesn’t everyone go vegetarian?

For the health-conscious vegetarian or flexitarian, complete rejection of animal products is not necessary. They can practice a healthy, balanced diet and still occasionally eat meat. However, for the ethically motivated, it is difficult to justify anything short of total abstention. If the suffering of animals matters at all, then in the absence of a good reason, harming them should be avoided (as well as paying money for it).

The ethical argument for not eating animals follows only if animals suffer, the suffering of animals matters, and eating them is not a good reason to cause them suffering. Research from psychology suggests that meat eaters seem to understand this logic, if only implicitly. When challenged about their meat consumption people tend to argue their case in one of three ways.

First, that there are good reasons for eating animals. When asked to justify why it is morally acceptable to use animals for food, many people tend to appeal to the necessity of eating meat (Angelina Jolie’s comment that being vegan almost killed her), how natural, normal, and nice it is, or that it’s impossible to be vegetarian.

Second, they tend to think that animals used as food are not really harmed. When thinking about animals as food, as opposed to living beings, concern for them is reduced, or the belief that they suffer or have the capacity to suffer is reduced.

Finally, there’s a belief that animals used as food don’t matter. There tends to be an inconsistency when thinking about animals. People in the West show concern over animals that are eaten in other cultures, such as dogs, but ignore things such as animal intelligence when thinking about the meat in their own diet.

Therefore it is rather easy to avoid the conclusion for vegetarianism and veganism. It requires a lot ("I have to stop eating bacon." "My friends will find me annoying.") and without the proper incentives, many are quick to convince themselves it is foolish or not worth it.

Jared Piazza is a lecturer in social psychology at Lancaster University