Dogs may not be inclined to return favors to people, at least when it comes to food.
The result, published on July 14 in PLOS ONE, is somewhat surprising as a previous study showed that dogs would return favors to other dogs in the form of food. In other studies, dogs helped their owners when people seemed to be trapped and canines were able to distinguish between useful and useless people. Therefore, it seems reasonable to think that dogs can match good deeds of humans.
To find out, comparative psychologist Jim McGetrick and colleagues at the University of Veterinary Medicine in Vienna trained dogs on how to use a button to get food from a nearby dispenser. Each dog was then paired with a human, visible in an adjacent enclosure, who pressed the button to dispense food into the dog enclosure. On several occasions, the dog was also paired with another human who did not press the button. When it was the dogs ’turn to offer food to their human mates, canines were no more likely to press the button to provide food to the useful human than to the miser.
Why didn’t dogs return food favors to humans? They may not be willing to do or may not be able to form this kind of complicated social contract by humans with humans. Or there is another possibility, the study authors point out: dogs simply did not understand what they were being asked to do, which could lead to how the experiment was designed.
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Science News spoke with McGetrick about the challenges of testing whether animals like dogs are capable of complex social behaviors. Their answers were edited for clarity and length:
SN: What aspects of the experiment influenced why a dog did not return the favor to a human being?
McGetrick: One possible explanation is the fact that dogs do not provide food to humans. We feed them all the time, but it’s not a natural thing for them to do. At the same time, it has been shown that dogs correspond to the reception of food with other dogs (although) adult dogs also do not normally provide food to other adult dogs. So if the argument applies that this is an unusual setup because dogs don’t provide food to humans, I think we also need to explain why it would be normal for one dog to provide food for another dog.
SN: If food trade wasn’t the problem, what else could have been thrown at it?
McGetrick: Another possible explanation for why they did not correspond is that the configuration is very abstract. In many previous reciprocity studies, there were very clear physical mechanisms: you pull a rope that pulls from a tray, or a box opens if you press a lever. The dog’s physical connection to the mechanism is very obviously related to the outcome, so it may be easier to understand for dogs. In our case, we used the food dispenser where the connection was not so obvious. That said, the dogs learned to press the button and get food. What they understand in this regard is another matter.
SN: Are there other elements of the experiment that the dogs didn’t understand?
McGetrick: I’m not sure the dogs understood that another individual was helping them. They seemed to certainly see the human. But even if dogs look, they can see the human face, they can see the human hand pressing the button, but they can never record that, “Oh, so I get the food” or “Oh, the human is doing something for me. "It is very difficult to know what they understand about the situation.
SN: Do you plan to follow any of these possible explanations?
McGetrick: At the moment, we do basically the same study but we use dogs as partners (instead of humans). You can boil our result up to two possibilities. One is that there were methodological issues. Or is this just the answer to the question: will dogs receive the help they receive from humans? And one way to really respond is to try them with other dogs with this setup. With the same setup, we should see reciprocity with other dogs. And if we don’t see reciprocity with other dogs as partners, then I would point more towards methodological issues.
SN: How hard is it to settle for a design for an experiment?
McGetrick: These are very artificial settings in which you are just trying to achieve something real, something that reveals something about nature and reality. And there are maybe 100 of these little decisions you make along the way, and many of them are just intuition. And those little decisions you make can be the difference between a positive outcome or a negative outcome.
SN: Posting negative results is weird. Why do you think it’s important?
McGetrick: My feeling is that it is becoming more common, especially in the field in which I work. If a study is well designed, well structured, and addresses a question, there is no reason why it should not be published regardless of the outcome. And it’s a big problem if the results aren’t published because they’re negative; hides a lot of important information. The result is the result. You can explain the reasons why you might have gotten that result, but it shouldn’t matter in any way.