Sometimes animals can be so judgmental, but not necessarily in the way you might think. Both dogs and monkeys show a preference for helpful people, finds a new study.

Recently, studies have shown that even in the first year of life, human babies can start to follow a moral code. "Some sense of good and evil seems to be bred in the bone," writes psychology professor Paul Bloom, Ph.D., of the Infant Cognition Center at Yale University, in the New York Times.

Knowing that babies react negatively to people who act unfairly or show negative intentions toward others, researchers at Kyoto University were curious whether some animal species might use similar cues to make social evaluations. They decided to look at capuchin monkeys and pet dogs.

For the first experiment, reports New Scientist, the monkeys watched as a person struggled to open a container with a toy inside. The person offered it to a second person who either helped open the container or refused to help. Then the monkey was offered a treat from both people.

If the second person helped, the monkey wasn't particular about accepting the treat from the person who struggled or the person who helped. But if the person refused assistance, in most cases, the monkey chose to take the treat from the person who struggled, not the person who refused to help.

Playing fair

capuchin monkey In the experiment, capuchin monkeys were less likely to take treats from people who were not being helpful or fair. (Photo: Eric Kilby/flickr)

In a follow-up experiment, the researchers tested the concept of fairness with the capuchins. The monkeys watched as two people each held three balls. One requested the balls from the other and they were handed over. Then the other asked for the balls to be returned. The person either returned the balls or refused. Then both people offered the monkey treats.

If the balls were returned as requested, the monkey had no preference when taking the treats. If the person refused to return the balls, the monkey was more likely to refuse to take treats from that person and would take them from the other person instead.

Then the researchers decided to see how dogs would respond. They had a dog's owner try unsuccessfully to open a container, while two people were on either side of them. Then they handed it to one of those people who either helped or didn't help, while the other person remained still. Afterwards, the two additional people offered the dog a treat.

The dogs typically had no preference where they got the treat if the first person helped their owners. But if the first person didn't help, they were more likely to choose the other person who had remained still during the experiment. The results were published in the journal Neuroscience & Biobehavioral Reviews.

Watch a video of the experiment here:

Lead researcher, comparative psychologist James Anderson, tells New Scientist that he thinks the results show that the animals make social evaluations in a somewhat similar way as human babies.

“If somebody is behaving antisocially, they probably end up with some sort of emotional reaction to it,” he says.

Human morality could potentially have roots in these social evaluations that babies learn to detect so early and that animals potentially detect in other animals and in us.

“I think that in humans there may be this basic sensitivity towards antisocial behaviour in others. Then through growing up, inculturation and teaching, it develops into a full-blown sense of morality,” says Anderson.

Mary Jo DiLonardo writes about everything from health to parenting — and anything that helps explain why her dog does what he does.