Critical Reasoning

Aphasia, an impairment of the capacity to use language, often occurs when a stroke damages the left half of the brain. Many people with stroke-related aphasia recover at least some capacity to use language within a year. One proposed explanation for such recoveries is that the right side of the brain, which is not usually the major language center, develops its latent language capabilities to compensate for the damage to the left side.

Which of the following, if true, most strongly supports the explanation?

a. In a study of local brain activity in people performing a language task, people with stroke-related aphasia showed higher activity levels in the right half of the brain than people who did not have aphasia

b. a blow to the head injuring the left half of the brain can result in impariment of the capacity to use language indistinguishable from that produced by a stroke

c. among people with stroke-related aphasia, recovering lost capacity to use language does not lead to any impariment of those capacities normally controlled by the right half of the brain.

d. a stroke that damages the left half of the brain often causes physical impairments of the right side of the body that lessen over time

e. studies of numerous people with aphasia have indicated that the function that govern language production and those that govern language comprehension are located in separate areas of the brain.

[spoiler]OA. A.
To me C is better even though C does not help us strengthen the idea that the right side compensates for the left side.
Reason for discounting A: there is no mention that the right side of brain has latent language capabilities to compensate for the damage to the left side. [/spoiler]

C does not strengthen that right side of the brain, which is not usually the major language center, develops its latent language capabilities to compensate for the damage to the left side. In a way it can be taken as that right side is not affected.

A says that people who do not have disease shown more usage of right side of brain but those with the disease shows more usage of left side of brain. and we know that left side is more responsible for language related tasks. so it strengthen the hypothesis.

C in no way strengthens the conclusion.
choice is between A and D in fact.

D does a co-relation hence POE'ed.

A gives clear indication that right side of the brain is performing the activity.

hence OA.

rishijhawar wrote: To me C is better even though C does not help us strengthen the idea that the right side compensates for the left side.
Reason for discounting A: there is no mention that the right side of brain has latent language capabilities to compensate for the damage to the left side.

first of all, think about what you just said -- you think c is better, even though c does not help us strengthen the idea that the right side compensates for the left side. sorry dude, but that is like saying, "even though i think c is incorrect, i think it's the best answer."

...

anyway, (a) actually does talk about the right side of the brain and language:

In a study of local brain activity in people performing a language task, people with stroke-related aphasia showed higher activity levels in the right half of the brain than people who did not have aphasia

so, during a language task people who had stroke-related aphasia used the right side of their bran more than did people who did not have aphasia. that basically means they were using the right side of their brain for language. so that totally strengthens the conclusion that people who have stroke-related aphasia use the right side of their brain to compensate for the damage to the left side. because these people who had aphasia, they were using the right side of their brain more than people who did not have aphasia (and therefore had full use of the left side). yep.