Think you're referring to Frank & Frank 1985. It's pretty neat in terms of the tests and responses. Lots of springs, levers, and other puzzle boxes with the wolves almost always eventually solving the puzzles unless the wolf was nervous or agitated by the situation for some reason.
"The wolves generally attacked each puzzle immediately upon release from the start box and persisted until either the problem was solved or time had run out. In contrast, the malamutes investigated puzzle boxes only until they discovered that the food was not easily accessible, after which they typically returned to the start box and performed a variety of solicitation and begging gestures toward Experimenter 1."
There's a couple others that have followed on that are kind of neat to and related. Marshall-Pescini, et al. looked at wolves and dogs ability to play shell games, recognize hidden food choices, and rationalize about whether risky choices that don't pay out are better than somewhat not preferable food pellets. Part of the result from that test was that dogs may just not care as much as wolves. That wolves with their diet and carnivore nature, have a much stronger preference toward what researchers believe is the preferable choice. Yet, from the wild dog perspective, they took a long time to have any testing preference for meat vs pellets, compared to the wolves immediate preference. [2]
Which is actually vaguely related to the topic article. You get a mediocre food pellet, but it solves the task, so you don't really care that much and move on. The "quality" of the food pellet in modern human existence has limited bearing.
[1] Frank & Frank 1985, "Comparative Manipulation Test Performance in Ten Week Old Wolves and Malamutes", https://www.researchgate.net/profile/Harry-Frank-2/publicati...
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4993792/