Tough Veritas

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Tough Veritas

by viidyasagar » Sat Jul 10, 2010 10:26 pm
Sylvia: Some psychologists attribute complex reasoning to reptiles, claiming that simple stimulus-response explanations of some reptiles behaviours, such as food gathering, cannot account for the complexity of such behaviour. But since experiments show that reptiles are incapable of making major alterations in their behaviour, for example, when faced with significant environment, these animals must be incapable of complex reasoning:

Which of the following is an assumption reqired by Slyvia's argument?

A. Animals could make major changes in their behaviour only if they were capable of complex reasoning
B. Simple stimulus-response explanations can in principle account for all reptile behaviours
C. Reptile behaviour appears more complex in the field than lab experiments reveal it to be
D. If reptiles were capable of complex reasoning, they would sometimes be able to make major changes in their behaviour
E. Complex reasoning and responses to stimuli cannot both contribute to the same behaviour

[spoiler]OA: D[/spoiler]
Source: — Critical Reasoning |

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by grockit_andrea » Sun Jul 11, 2010 5:35 am
viidyasagar wrote:Sylvia: Some psychologists attribute complex reasoning to reptiles, claiming that simple stimulus-response explanations of some reptiles behaviours, such as food gathering, cannot account for the complexity of such behaviour. But since experiments show that reptiles are incapable of making major alterations in their behaviour, for example, when faced with significant environment, these animals must be incapable of complex reasoning:

Which of the following is an assumption reqired by Slyvia's argument?

A. Animals could make major changes in their behaviour only if they were capable of complex reasoning
B. Simple stimulus-response explanations can in principle account for all reptile behaviours
C. Reptile behaviour appears more complex in the field than lab experiments reveal it to be
D. If reptiles were capable of complex reasoning, they would sometimes be able to make major changes in their behaviour
E. Complex reasoning and responses to stimuli cannot both contribute to the same behaviour

[spoiler]OA: D[/spoiler]
Sylvia's argument is that reptiles are incapable of making major alterations in their behavior, and therefore reptiles are incapable of complex reasoning. The assumption can be understood using a formal logic-based approach:

Reptiles ==> can't make major alterations/changes in behavior

Reptiles ==> incapable of complex reasoning

How do you get from "can't make major alterations/changes in behavior" to "incapable of complex reasoning"? Choice D can be represented like this:

Capable of complex reasoning ==> can make major changes/alterations in behavior

The contrapositive of that statement looks like this:

Can't make major changes/alterations in behavior ==> incapable of complex reasoning

Now combine the evidence and conclusion above with this assumption contrapositive:

Reptiles ==> can't make major alterations/changes in behavior (evidence)
Can't make major changes/alterations in behavior ==> incapable of complex reasoning (assumption)
Reptiles ==> incapable of complex reasoning (conclusion)

If A ==> B, if B ==> C, therefore if A ==> C
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by ssgmatter » Sun Jul 11, 2010 6:35 am
viidyasagar wrote:Sylvia: Some psychologists attribute complex reasoning to reptiles, claiming that simple stimulus-response explanations of some reptiles behaviours, such as food gathering, cannot account for the complexity of such behaviour. But since experiments show that reptiles are incapable of making major alterations in their behaviour, for example, when faced with significant environment, these animals must be incapable of complex reasoning:

Which of the following is an assumption reqired by Slyvia's argument?

A. Animals could make major changes in their behaviour only if they were capable of complex reasoning
B. Simple stimulus-response explanations can in principle account for all reptile behaviours
C. Reptile behaviour appears more complex in the field than lab experiments reveal it to be
D. If reptiles were capable of complex reasoning, they would sometimes be able to make major changes in their behaviour
E. Complex reasoning and responses to stimuli cannot both contribute to the same behaviour

[spoiler]OA: D[/spoiler]
Is there another way to handle this...i mean using the negation technique
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by grockit_andrea » Sun Jul 11, 2010 7:54 am
ssgmatter wrote:
viidyasagar wrote:Sylvia: Some psychologists attribute complex reasoning to reptiles, claiming that simple stimulus-response explanations of some reptiles behaviours, such as food gathering, cannot account for the complexity of such behaviour. But since experiments show that reptiles are incapable of making major alterations in their behaviour, for example, when faced with significant environment, these animals must be incapable of complex reasoning:

Which of the following is an assumption reqired by Slyvia's argument?

A. Animals could make major changes in their behaviour only if they were capable of complex reasoning
B. Simple stimulus-response explanations can in principle account for all reptile behaviours
C. Reptile behaviour appears more complex in the field than lab experiments reveal it to be
D. If reptiles were capable of complex reasoning, they would sometimes be able to make major changes in their behaviour
E. Complex reasoning and responses to stimuli cannot both contribute to the same behaviour

[spoiler]OA: D[/spoiler]
Is there another way to handle this...i mean using the negation technique
I don't usually recommend trying to identify an answer based just on the negation technique; it's time-consuming and there's a lot of room for error. However, if you want to double-check an answer after you've chosen it, or are just trying to decide between two choices, negation can be a great option. The negation of D would be something like "If reptiles were capable of complex reasoning, they would not be able to make major changes in behavior." Since the reptiles can't make major changes in behavior, this negated assumption would make the conclusion that reptiles aren't capable of complex reasoning invalid.
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by outreach » Sun Jul 11, 2010 11:00 am
i narrowed down to A and D
but A looks strong hence chose D
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by tanviet » Mon Jul 12, 2010 12:45 am
D is correct but D use formal logic IF A THEN B, IF NOT B THEN NOT A

formal logic is not tested on GMAT though it is tested on LSAT.

I think we should not study this question.

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by jaghsi » Mon Jul 12, 2010 12:59 am
A is definitely out. "Animals" is wrong. We are talking about reptiles. All replites are animals but not all animals are replites. D seems the best choice.

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by grockit_andrea » Fri Jul 16, 2010 10:07 am
duongthang wrote:D is correct but D use formal logic IF A THEN B, IF NOT B THEN NOT A

formal logic is not tested on GMAT though it is tested on LSAT.

I think we should not study this question.
Duongthang, I've seen several posts by you in which you say that formal logic is not tested on the GMAT and should therefore not be studied. While knowledge of formal logic isn't necessary on the GMAT, I firmly believe that it will help on many questions in the critical reasoning section; the linear thinking that is promoted by formal logic can help test-takers understand some of the reasoning on the GMAT, particularly in terms of inferences or assumptions. For instance (I'm sure this is neither the best example nor the only example, but it's illustrative and it also happens to be on the page I was just looking at) both OG 12 CR 20 and OG 12 CR 33 can absolutely be solved using the principles of formal logic.

The GMAT isn't designed to require formal logic, and if you don't find it helpful, then of course it's not worthwhile for you to study it. But it's helpful to many people, and since there are questions on the test that can be understood using it, I think it's great for people who are interested to gain an understanding of it.
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by hims » Sat Jul 17, 2010 7:06 am
Andrea,

Don't you think that D is a re-statement rather than an assumption ?
Also, why not A?

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by grockit_andrea » Sat Jul 17, 2010 7:56 am
hims wrote:Andrea,

Don't you think that D is a re-statement rather than an assumption ?
Also, why not A?

Thanks,
Himanshu
No, I don't think that D is a restatement; the argument never says what would happen if reptiles were capable of complex reasoning. In a tightly-written argument like this one, the correct assumption fits in like a puzzle piece; it sounds familiar because it's directly filling the little gap in the argument, using the terms from the argument. But it's not restating anything that was already written.

And A is incorrect because it's not REQUIRED, which is what the question is asking for. A could be represented like this:

Can make major changes in behavior ==> Capable of complex reasoning

or the contrapositive:

Incapable of complex reasoning ==> Can't make major changes in behavior


Going back to the original formal logic version of the argument, we have this:

Reptiles ==> can't make major alterations/changes in behavior (evidence)

Reptiles ==> incapable of complex reasoning (conclusion)

The assumption needs to bridge the gap between the evidence and conclusion, by fitting in the way that the contrapositive of D does. A doesn't fit in that way; we need a statement that says "B ==> C" but A says "C ==> B".
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by hims » Sat Jul 17, 2010 9:11 am
Yeah...I got it now! Many thanks!

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by arora007 » Sun Jul 18, 2010 9:12 pm
great!! got a D first attempt... andrea if you could please help me... how i can reduce the time on CR questions...in general.

I clocked 122 seconds for this problem.

I read the argument, read the question stem. Before going to the choices I rerun what was being asked... in this case..
"food gathering- not complex , major alterations in behavior not possible in changed environment=>not capable of complex reasoning"-->correct answer should address "changed behavior"

A reject contains strong ONLY
B reject contains strong ALL
C read the choice and then re-read the argument.. keep it as a possible choice.
D read the choice and then re-read the argument... keep it as a possible choice.
E does not address changed behavior.

I read C and D again and then look at the question stem, say that C cannot be the question stem... and I prononuce D as the answer.

I lose time, though not accuracy...when I am stuck between choices... what should be my approach??
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by grockit_andrea » Sat Jul 24, 2010 4:12 am
arora007 wrote:great!! got a D first attempt... andrea if you could please help me... how i can reduce the time on CR questions...in general.

I clocked 122 seconds for this problem.

I read the argument, read the question stem. Before going to the choices I rerun what was being asked... in this case..
"food gathering- not complex , major alterations in behavior not possible in changed environment=>not capable of complex reasoning"-->correct answer should address "changed behavior"

A reject contains strong ONLY
B reject contains strong ALL
C read the choice and then re-read the argument.. keep it as a possible choice.
D read the choice and then re-read the argument... keep it as a possible choice.
E does not address changed behavior.

I read C and D again and then look at the question stem, say that C cannot be the question stem... and I prononuce D as the answer.

I lose time, though not accuracy...when I am stuck between choices... what should be my approach??
Speeding up without losing accuracy is tough; there's no real foolproof way to do it, and 122 seconds seems reasonable to me for this question. But as far as I'm concerned, the best way to improve your speed is to improve your ability. Once you're able to consistently get questions right, you'll gradually start being able to do them faster. So, just like with so many other things on the GMAT, I think the best way to accomplish your goal is to keep practicing and reviewing.
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by arora007 » Sat Jul 24, 2010 7:42 am
Thanx Andrea, I think you are right... I have been able to consistently get over 85% of my CR right...and with more practice I am able to do it a bit faster too... One more thing which I notice is...something like a "warmup period...". After a good 8-10 practice questions, I am able to get answers more quickly and correctly.
I plan to do a few CR and SC questions on test day which is just 13 days from today!
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by agganitk » Wed Jul 28, 2010 8:23 am
Hi andrea,
What about the word sometimes in option D ? Why have you ignored it? Please explain