Dogs prefer to share food with friends: study

Dogs share food with their friends just like humans, according to a new study which also found that the animals are not as generous with strangers.
Researchers used a complex task set-up to confirm the prosocial behaviour of dogs. The experiment showed that dogs continued to prefer familiar partners.
The researchers from University of Veterinary Medicine in Austria had earlier showed that dogs share food rewards with other dogs.
Using a bar-pulling task, the dogs delivered the treats to partner dogs - especially if these were already known to them.
However, the increased complexity of the task influenced the readiness with which the dogs delivered a food reward to another animal.

The new study confirmed that the chosen method affects the result and is much more dependent on social proximity than had previously been assumed.

For the study, the dogs had to recognise special objects in form of tokens in order to deliver a food reward to the other dog.
"This time we not only tested a different experimental set-up but also the level of difficulty. The dogs were first trained to touch a token in exchange for a food reward for themselves," said Rachel Dale from the university.
"They were then trained to recognise two more tokens: one that resulted in a reward being delivered to a partner dog and another which did not," Dale said.

The researchers tested whether it made a difference to the donor dog if the receiver was familiar or a stranger and whether the presence of another dog was enough to trigger generous behaviour in the test dog even if the partner had no access to the food.
The test set-up consisted of two enclosures. The test dog was trained to wait on a specific location in one enclosure until the researchers revealed a board containing the tokens.
The dog could then choose to deliver a food reward to the receiver dog or not. In the first test, either a familiar dog or a stranger sat in the receiver enclosure. The dogs could see each other during the experiment.

In the second test, the receiver enclosure remained empty but the other dog was present in the testing room.
In a third test, the dogs were alone in the entire set-up. At the end of each test series, the donor animals could reward themselves by being allowed to touch the token that delivered the food reward to them.
This was done to ensure that the dogs remained motivated and unstressed and did not become distracted by an unfamiliar dog.
The experiment confirmed that dogs continue to exhibit prosocial behaviour despite the more complex task.
The dogs clearly showed a preference for sharing the food reward with a familiar dog.

The study appears in the journal PLOS ONE.