Passage Summary: Researchers found that if you reward one dog for a trick but ignore the other, the ignored dog eventually quits doing the trick.

Conclusion: Dogs stop obeying because they dislike being treated unfairly compared to their peers.

Reasoning: In a study, dogs that were consistently unrewarded while their partners received treats eventually stopped following commands.

Analysis: To evaluate this, we need to know if the dog stopped because of the unfairness or simply because it wasn't getting paid. If a dog stops obeying whenever rewards cease—regardless of what the other dog gets—then unfairness isn't the primary cause. Look for an answer choice that asks how dogs behave when neither dog gets a reward. This would help isolate whether the presence of the rewarded partner is the actual trigger for the disobedience.