Children think farm animals deserve to be treated as well as human beings but lose this belief in adolescence, a groundbreaking study has found. Researchers from the universities of Exeter and Oxford asked a group of British children aged nine to 11, young adults aged 18 to 21 and older men and women about their attitudes to different sorts of animals. In general, the children said farm animals and human beings should be treated the same and found eating animals less morally acceptable than both sets of adults. The findings suggest that “speciesism” – a moral hierarchy that gives different value to different animals – is learned during adolescence, according to the study. “Humans’ relationship with animals is full of ethical double standards,” said the lead author, Luke McGuire, a lecturer at the University of Exeter who specialises in social and moral development. “Some animals are beloved household companions, while others are kept in factory farms for economic benefit. Judgments seem to largely depend on the species of the animal in question: dogs are our friends, pigs are food.” The report says an important aspect of the human mind is “moral acrobatics”: people can hold ethical values that contradict each other and employ moral double standards. But the origins of moral acrobatics relating to animals is poorly understood and the researchers say this new study provides some of the first evidence examining the differences in how children and adults think about animal treatment. Among other tasks, participants in the study were presented with pictures including a farm animal and companion animals and asked to categorise them as “food”, “pet” or “object”. They were asked how animals were treated, and how they should be treated. Children did not judge all animals to be equal. They concluded, in fact, that dogs ought to be treated better than pigs – but also that pigs ought not to be treated differently from humans. The two sets of adult groups said pigs ought to be treated less well than dogs, while humans and dogs ought to be treated the same. McGuire said the study suggests that while children think farm animals and humans ought to be treated equally well, by adulthood people believe that companion animals and humans ought to be treated better. He said children rated eating animals as significantly less permissible than young adults and adults did. “Something seems to happen in adolescence, where that early love for animals becomes more complicated and we develop more speciesism,” said McGuire. “It’s important to note that even adults in our study thought eating meat was less morally acceptable than eating animal products like milk. So aversion to animals – including farm animals – being harmed does not disappear entirely.” McGuire said that while adjusting attitudes was a natural part of growing up, the “moral intelligence of children” could be valuable. He said: “If we want people to move towards more plant-based diets for environmental reasons, we have to disrupt the current system somewhere. For example, if children ate more plant-based food in schools, that might be more in line with their moral values, and might reduce the normalisation towards adult values that we identify in this study.” The paper, published in the journal Social Psychological and Personality Science, is titled “The development of speciesism: age-related differences in the moral view of animals”.