Dogs were put in four different cases. Two were neutral cases, while the other two were variables. In each case, the dogs watched while their owner asked a researcher for help opening a jar.
In one case, the researcher helped the owner open the jar. The dogs apparently approved. And in the two neutral cases, the researcher couldn’t help the owner open a jar. Not great, but they didn’t refuse to help. Apparently the dog was willing to forgive that.
However, when the researcher outright refused to help open the jar, that was different. The dogs noticed, and clearly weren’t happy about it. In fact, when the researcher who refused to help their owner offered the dogs treats later, the dogs refused to accept the treats.