Getting dogs to share food with you may not be all that easy, new research suggests. In a series of experiments, scientists found that dogs didn’t reciprocate the act of giving food to helpful humans. Though the results may be due to how the experiment was conducted, it could also suggest food-giving just isn’t one of the ways dogs are naturally cooperative toward us.

Plenty of studies (and owner anecdotes) have suggested that dogs have a rich capacity for social interaction, which likely includes the ability to tell friend from foe and to help friends when given the opportunity. In past studies, for instance, dogs have been shown to reward other familiar dogs by providing them access to food when they had no chance to get the food themselves. In other experiments, dogs were more likely to help their owners get out of a box when the owners called out in distress and to avoid humans who were previously shown to be uncooperative with their owners.

In this new study, published Wednesday in PLOS-One, researchers at the University of Veterinary Medicine in Vienna, Austria wanted to see if dog cooperation would extend to reciprocal food sharing with people.

The team trained around three dozen dogs to operate a food-giving dispenser via a button. Then they introduced the dogs to a pair of initially unfamiliar humans in an enclosed space. One human would regularly give the dogs treats by pressing a similar button in an adjacent room the dogs could look into, while the other person didn’t (for the sake of scientific integrity, all dogs got the same amount of treats by the end, no matter what). Afterward, the dogs were given the chance to push their button, having been trained earlier to recognize that pushing it would give food to the human but not themselves. After this first test was done, the dogs were allowed to freely interact in the larger room with the humans if they chose.

Across two experiments, the second intentionally made to be less complex and shorter, the researchers found no link between a person’s earlier helpful behavior toward a dog and that dog’s later willingness to pay them back in human treats. The dogs also weren’t more likely to spend time around the generous humans afterward. As the authors put it succinctly, “In our study, pet dogs received food from humans but did not return the favor.”

Research into the behavior and cognition of animals is often a tricky beast. Studies tend to be small, and since we can’t verbally communicate with the test subjects, there’re always room for interpretation in the results. And there’s always the possibility of hidden factors that could influence the outcome of a study. The authors themselves are quick to offer that same caution, pointing out that there are other explanations for their findings beyond the obvious headline that dogs aren’t good sharers. Indeed, given the other evidence suggestive of dogs’ willingness to be altruistic, they argue that the findings are probably more complicated than they seem on the surface.

For one, the authors still worry that the experimental design could have been too complex for the dogs to fully understand what was going on, even after their efforts to simplify it in the second round. The study required dogs to associate a button with food giving, then to remember that a human pressing another button in another room would give them food, then again to remember that pressing their own button would give that person food. Somewhere along the way, something may have gotten lost in translation, to the point where the dogs simply didn’t recognize that their partner was trying to be helpful or unhelpful.

Even if these issues aren’t significant, it may still be true that dogs will happily aid helpful people, just not in this specific circumstance. The authors note that our relationship with dogs tends to go one way when it comes to food; it’s not them giving us their dinner scraps. In a different context, like helping people trapped or in danger, a sense of charity among dogs might be there. Or they might be more willing to help or not help people that they have more familiarity with. Future studies might be able to confirm or refute these potential caveats by using a different experimental setup, training the dogs for longer, or having the partners be other dogs instead of humans, the authors say.

“It is plausible that aspects of the experimental design hindered the emergence of any potential reciprocity,” they wrote. “However, it is also possible that dogs are simply not prosocial toward humans in food-giving contexts.”

In many ways, this study isn’t just about dogs and their ability to share—it’s about our limitations in trying to understand the inner workings of our oldest friends, even after millennia spent together. Cats, however, are likely just as disloyal as you suspect.