Official Explanation

Argument Evaluation

Which one of the five experimental outcomes, if added to the information given, would most strengthen the evidence for the scientist's conclusion?

There were three enclosures, two of which contained a dog. Only one of these contained a familiar dog. The dogs released more food to familiar dogs than to unfamiliar dogs. The scientists thereby concluded that dogs are more motivated to help familiar dogs than they are to help unfamiliar dogs.

However, it is possible that releasing the food to the familiar dog could have been motivated by other reasons. For example, the dog could simply be trying to communicate with the familiar dog rather than necessarily trying specifically to help this dog.

If the dogs released more food to a familiar dog while it was contained in an enclosure than when it was not enclosed yet nearby and visible, this would strengthen the idea of trying to “help” the other dog.

A. This information would weaken the scientist's argument. It introduces information suggesting the presence of a confounding variable in the experimental setup. That is, if the behavior was encouraged by a familiar person, we would not be able to tell whether it was this person's presence or the presence of the other dog that increased the behavior.

B. This would suggest that the dog's activation of the lever was not contingent on providing food to another animal. In other words, if the dog provides food even when there is no animal to provide food for, then it follows that the presence of the other dog is irrelevant to this behavior.

C. The experimental setup described here introduces the factor of friendliness. Adding this extra factor could easily confound testing of the original hypothesis, which suggested that simple familiarity increased the behavior.

D. The experimental setup described here introduces a factor of food interest. Adding this extra factor could easily confound testing of the original hypothesis, which suggested that simple familiarity increased the behavior.

E. Correct. This information would strengthen the hypothesis that a desire to help a familiar dog was operative in the dog's behavior.

The correct answer is E.