“In our study, pet dogs received food from humans but did not return the favor.”
I guess they have never been on a hunt for pheasant or ducks with dogs.
The dogs wouldn’t bring back cooked pheasants or ducks.
I had the same thought, but I think they’re after something different. They probably know that you can train a dog to do that, what these people were trying to find out was if a dog could, on it’s own, decide to behave in a altruistic way.
Anyone who’s ever trained a dog probably knows that they won’t do that, and that we rely on that in order to train them.
We show them what we want them to do, and they get a food treat as a reward.
When they come back to you with a bird and say ”Here. Cook this for me.”