Psychologist: In an experiment, volunteers were asked to solve

Explanation

Psychologist: In an experiment, volunteers were asked to solve abstract arithmetic problems while their brains were being scanned. The brain scans revealed considerable activity in the linguistic-processing centers of the brain. However, it is likely that this activity reflected passing thoughts that are not an indispensable part of arithmetical reasoning processes.

The passage presents the following conclusion:

it is likely that this activity (in the linguistic-processing centers of the brain) reflected passing thoughts that are not an indispensable part of arithmetical reasoning processes

No evidence for the conclusion is provided.

Which of the following, if true, provides the strongest justification for the psychologist's judgment?

The question asks which choice "provides the strongest justification for the psychologist's judgment." Since "the psychologist's judgment" is another way of saying "the conclusion," the correct answer will be evidence that supports the conclusion.

A) The volunteers who reported that they had used language in their minds when solving the arithmetic problems were the most efficient in solving them.

This choice weakens, rather than strengthens, the case for the conclusion.

After all, if this choice is true, then the activity in the linguistic-processing (language-processing) centers of the brain may not have "reflected passing thoughts that are not an indispensable part of arithmetical reasoning processes," but rather reflected thoughts that were an important part of the arithmetical reasoning processes of these volunteers.

Eliminate.

B) The brain scans revealed activity in several parts of the brain other than the linguistic-processing centers.

This choice could be taken as slightly strengthening the argument. After all, by confirming that there was activity in other parts of the brain, this choice shows that it's possible that the activity in the linguistic-processing centers was not reflective of an indispensable part of the arithmetical reasoning process.

After all, if there were not activity in other parts of the brain, then the activity in the linguistic-processing centers would have been the only activity occurring when the volunteers were solving the problems, meaning that it was almost certainly indispensable to the arithmetical reasoning process.

At the same time, this choice may not be correct because the idea that there would be a situation in which there was activity in only one area of the brains of volunteers solving problems isn't really realistic since there would have to be some activity in different parts of people's brains if their brains were functioning normally. So, my guess is that the question-writer didn't consider that situation realistic and thus didn't figure the idea of that situation into the reasoning about this choice.

In addition, it's a good bet that the question-writer was looking for something that more clearly shows that the activity in the linguistic-processing centers was not indispensable to the mathematical reasoning process than this choice does.

So, I think GMAC made a mistake including this choice since it does strengthen the argument in a way, but I'm not expecting it to be the correct answer.

Keep for now, but expect to find a better choice.

C) In experiments in which volunteers have been asked to perform mental tasks other than arithmetic while their brains were being scanned, activity was often present in the linguistic-processing centers of the brain.

We could get the impression that this choice strengthens the argument by showing that activity in the linguistic-processing centers of the brain is involved in "mental tasks other than arithmetic" and that therefore any activity in those centers is not related to doing arithmetic.

However, the truth is that the fact that some activity that occurs in the linguistic-processing centers is not related to doing arithmetic does not mean that all activity that occurs in those centers is not related to doing arithmetic.

After all, it's possible that the linguistic-processing centers handle a variety of types of tasks. So, while some activity in the linguistic processing centers may not be arithmetic related, other activity in those centers could be essential to doing arithmetic.

Eliminate.

D) Studies have found that some people who have suffered significant head injuries are still capable of solving arithmetic problems.

This choice provides no clear information about linguistic-processing centers since it doesn't say anything about how the injuries affected or did not affect the people's brains.

If it said that people were capable of solving arithmetic problems after injuries to their linguistic-processing centers, then it might strengthen the argument, but it doesn't say anything that specific about the head injuries.

Eliminate.

E) A second study using the same problems, but with professional mathematicians as research subjects, found that some solved the problems without any significant activity in their linguistic-processing brain centers.

This choice provides some clear support for the conclusion that it is likely that the activity in the linguistic-processing centers reflected passing thoughts that are not an indispensable part of arithmetical reasoning processes. After all, if professional mathematicians can solve the problems without such activity occurring, then we can see that that activity is not reflective of an "indispensable," meaning "necessary," part of arithmetical reasoning processes.

The correct answer is (E).