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Linguistic capabilities and the brain

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by pakaskwa » Mon Apr 06, 2009 3:31 pm
For most people, the left half of the brain controls linguistic capabilities, but some people have their language centers in the right half. When a language center of the brain is damaged, for example by a stroke, linguistic capabilities are impaired in some way. Therefore, people who have suffered a serious stroke on the left side of the brain without suffering any such impairment must have their language centers in the right half.

Which of the following is an assumption on which the reasoning in the argument above depends?

A. No part of a person’s brain that is damaged by a stroke ever recovers.
B. Impairment of linguistic capabilities does not occur in people who have not suffered any damage to any language center of the brain.
C. Strokes tend to impair linguistic capabilities more severely than does any other cause of damage to language centers in the brain.
D. If there are language centers on the left side of the brain, any serious stroke affecting that side of the brain damages at least one of them.
E. It is impossible to determine which side of the brain contains a person’s language centers if the person has not suffered damage to either side of the brain.
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Source: — Critical Reasoning |

by gmat740 » Mon Apr 06, 2009 9:09 pm
D. If there are language centers on the left side of the brain, any serious stroke affecting that side of the brain damages at least one of them.
Negate this

serious stroke is not able to damage even one of the language centers

so, the language centers remain in the left side inspite of the stroke which happened to be on the left side.

so our conclusion that
people who have suffered a serious stroke on the left side of the brain without suffering any such impairment must have their language centers in the right half.

conclusion is weakened


SO this is the correct answer[/quote]
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by delhiboy1979 » Mon Apr 06, 2009 11:07 pm
I had narrowed it to A and D. D does look the better option.
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by ketkoag » Tue Apr 07, 2009 5:48 am
IMO : B coz in this option, a relation between linguistic capabilities and language centers is given and that is what required to fill the gap in the reasoning.
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by gmat740 » Tue Apr 07, 2009 6:46 am
can we have the OA Please?
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by mjjking » Tue Apr 07, 2009 7:11 am
The OA is clearly D, because the assumption that must be true for the argument to hold is that ANY stroke will damage at least one language center in the brain. Then, if somebody suffers a stroke in the left side BUT his language abilities are unaffected he must have all of his language centers in the right part.
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by pakaskwa » Tue Apr 07, 2009 11:50 am
The OA is E. It's clearly a wrong answer. The source of this question is from some online GMAT test prep. It's not very reliable. I think D is the only reasonable answer.
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by anshulseth » Thu Apr 09, 2009 12:51 am
IMO answer is B.

Logic is to use transposition, as its a causation question.

If damage to lang center of brain implies loss of linguistic capabilities.

Then if linguistic capabilities are not impaired, then lang center of brain is not damaged.

Hence, B
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by hk » Thu Apr 09, 2009 7:12 am
I think the answer is E.

Here my take: The first sentence tells us that the Language center can be either on the left side or on the right side of the brain. The second tells us that if the language center is damaged, then the person looses the language capability. And then the author concludes that the way to find which side of the brain the language center is by analyzing if the damage done to left side does not affect the language skills then the guy has the language center in the other side. This argument is based on the theory that the language center can be on either side. Hence the author assumes that unless the guy has a stroke and damages one side, there is no way to tell which side of his brain houses the language centers!!! This E is the answer!!!.

Correct me if i'm wrong.
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by dendude » Thu Apr 09, 2009 9:36 am
hk wrote:I think the answer is E.

Here my take: The first sentence tells us that the Language center can be either on the left side or on the right side of the brain. The second tells us that if the language center is damaged, then the person looses the language capability. And then the author concludes that the way to find which side of the brain the language center is by analyzing if the damage done to left side does not affect the language skills then the guy has the language center in the other side. This argument is based on the theory that the language center can be on either side. Hence the author assumes that unless the guy has a stroke and damages one side, there is no way to tell which side of his brain houses the language centers!!! This E is the answer!!!.

Correct me if i'm wrong.
No I dont think this reasoning is correct.
An assumption has to have a bearing on the conclusion. It cannot be a finding.
Yes the argument is based on the theory that the language center can be on either side but the conclusion does not assume that we need to determine which side houses the LC.
The conclusion states that the left side of the brain suffered a stroke and there was no impairment so the LC is on the right.
Clearly this conclusion assumes that if the LC had been on the left, the stroke would have damaged it and since there's no impairment thats why the LC has to be on the right.

The answer should be D.
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by jainrahul1985 » Thu Jun 02, 2011 6:38 am
Is the OA B . Experts request you to confirm . Please correct me if I am wrong
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by kevincanspain » Thu Jun 02, 2011 7:08 am
Whether impairment of language capabilities results only from damage to the language center of the brain is irrelevant. What we need to consider is the following:

Are you convinced that somebody who suffers a stroke on the left side of his brain and nevertheless does not experience any linguistic impairment must have his language centers on the other half?

Here's an analogy:

Burglars broke into Karen's house and made off with a lot of her antiques and electronic equipment, all of which were located on the ground floor. The burglars heard the police come and fled without going up to the second floor. Karen later reported that her jewels had not been removed from the house. Obviously, these jewels were located on the second floor.
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by GMATGuruNY » Thu Jun 02, 2011 7:46 am
pakaskwa wrote:For most people, the left half of the brain controls linguistic capabilities, but some people have their language centers in the right half. When a language center of the brain is damaged, for example by a stroke, linguistic capabilities are impaired in some way. Therefore, people who have suffered a serious stroke on the left side of the brain without suffering any such impairment must have their language centers in the right half.

Which of the following is an assumption on which the reasoning in the argument above depends?

A. No part of a person�s brain that is damaged by a stroke ever recovers.
B. Impairment of linguistic capabilities does not occur in people who have not suffered any damage to any language center of the brain.
C. Strokes tend to impair linguistic capabilities more severely than does any other cause of damage to language centers in the brain.
D. If there are language centers on the left side of the brain, any serious stroke affecting that side of the brain damages at least one of them.
E. It is impossible to determine which side of the brain contains a person�s language centers if the person has not suffered damage to either side of the brain.
Learn to recognize the common flaws.

This argument exhibits a shift in language.
The premise is about a stroke.
The conclusion is about the language centers.

The argument assumes a connection between these two ideas: it assumes that a stroke must damage the language centers.

Answer choice D states this assumption:

If there are language centers on the left side of the brain, any serious stroke affecting that side of the brain damages at least one of them.

The correct answer is D.
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by tanviet » Wed Jun 08, 2011 8:33 pm
I agree D is correct

but why A is wrong?, please, help me out.
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by cans » Wed Jun 08, 2011 9:57 pm
Assumption joins premise to the conclusion/reasoning.
And thus assumption strengthens the reasoning.
A) on the other hand weakens the argument.
IMO D
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