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Q23 - A scientific study provides evidence that crows

by ohthatpatrick Thu Nov 02, 2017 1:28 pm

Question Type:
Necessary Assumption

Stimulus Breakdown:
Conclusion: Crows can recognize scary people and tell other crows.
Evidence: Researchers in masks had trapped wild crows and later released them. When people wearing the same masks came back to that area years later, the crows raged on them.

Answer Anticipation:
This is a classic Explanation/Interpretation template:
PREMISE - a curious fact, a statistical change, a correlation
CONCLUSION - someone's explanation for / interpretation of that background fact.

Here, the friend is trying to explain/interpret the fact that when people came back years later in the same masks, the crows went nuts on them. The author interprets this to mean that the original crows who were trapped told other crows about these masked people, and since the crows now recognize these people as a threat, they went on the attack.

Whenever we evaluate this template, we ask two different, though related, questions:
1. Is there some OTHER WAY to explain the background fact (i.e. what ELSE could explain why crows attacked the masked people years later?)
2. How plausible is the AUTHOR'S INTERPRETATION (i.e. can crows actually remember features of human appearance? can crows actually communicate that threat to other crows?)

For Necessary Assumption, I anticipate that we will rule out an ALTERNATE EXPLANATION for why the crows attacked. (Maybe the masks are just scary. Maybe the people were unknowingly getting too close to some crows' nests. Maybe it was just the original crows, and they never "passed their concerns" to other crows)

Correct Answer:
A

Answer Choice Analysis:
(A) Yes, this should work. If you negate it, you get the idea that "all the angry crows were the original crows". That weakens the notion that the original crows "passed their concerns" to other crows. It supplies a different interpretation of the same crow attack.

(B) "ALWAYS" is way too strong to be necessary here.

(C) "MOST" of "ANY" species is way broader than the author needs to assume.

(D) The author doesn't need to assume anything about any other situation. Her argument is just about this scientific study and whether it provides evidence that crows CAN (at least once) do something. And of course "most" = "automatic garbage" 99% of the time on Necessary Assumption.

(E) The author thinks that crows are possibly capable of recognizing threatening people. That's it. She didn't commit herself to any specific distinctions about "can't do faces, but CAN do masked vs. unmasked)

Takeaway/Pattern: This question really hinges on people noticing both claims made in the Conclusion. The correct answer, when negated, doesn't attack the idea of recognizing threatening people. It attacks the idea that the crows passed their concerns on to other crows. This study provides no evidence of that unless some of the angry crows were not part of the original crew. We need at least some "new" crows to be attacking if we think this says anything about the ability of crows to tell other ones about danger they've encountered.

#officialexplanation
 
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Re: Q23 - A scientific study provides evidence that crows

by mattop6 Wed Nov 22, 2017 1:58 am

I had a question that I was hoping someone could address. I understand why answer choice (B) is not necessary. However, I was wondering, would it be necessary to assume that crows shriek and dive-bomb only in the presence of something threatening/a threatening situation?

If this was not assumed, then the premise would not support the conclusion because the crows could be engaging in the behavior for another reason (and not because of recognizing a threat).

Would very much appreciate any clarification/confirmation.

Thanks.
 
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Re: Q23 - A scientific study provides evidence that crows

by andrewgong01 Wed Nov 22, 2017 2:55 am

mattop6 wrote:I had a question that I was hoping someone could address. I understand why answer choice (B) is not necessary. However, I was wondering, would it be necessary to assume that crows shriek and dive-bomb only in the presence of something threatening/a threatening situation?

If this was not assumed, then the premise would not support the conclusion because the crows could be engaging in the behavior for another reason (and not because of recognizing a threat).

Would very much appreciate any clarification/confirmation.

Thanks.



I do not think it is necessary because like the original Choice B that is too strong. The negation is "Crows shriek and dive in other situations too" . That does not destroy the argument because all we are saying/doing then is that there are other reasons for the shrieking too but that does not cast doubt on the argument because the author could easily come back and argue "I never said shrieking was exclusive to this behavior ; i just said there is some relationship between shrieking and threats but other relations can exist too".

However, removing the "only" would make it a NA where it is "crows shriek in the presence of a dangerous situation" because the negation of that is that they do NOT shriek <-- this would destroy the argument. The key was the word "only".
 
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Re: Q23 - A scientific study provides evidence that crows

by JamesM914 Tue Nov 28, 2017 11:48 pm

I don't agree with answer choice A at all. While I understand why the other answer choices are wrong, answer A does not seem necessary to the question. Why? Because the stimulus said that crows are capable of recognizing threatening people AND can even pass their concerns to other crows. So even if the crows were the same ones as before, that wouldn't hurt the argument because it shows that crows are capable of recognizing threatening people, whereas passing concerns to other crows is an ADDITIONAL criteria, but it doesn't necessarily have to be met.
 
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Re: Q23 - A scientific study provides evidence that crows

by andrewgong01 Wed Nov 29, 2017 3:38 am

JamesM914 wrote:I don't agree with answer choice A at all. While I understand why the other answer choices are wrong, answer A does not seem necessary to the question. Why? Because the stimulus said that crows are capable of recognizing threatening people AND can even pass their concerns to other crows. So even if the crows were the same ones as before, that wouldn't hurt the argument because it shows that crows are capable of recognizing threatening people, whereas passing concerns to other crows is an ADDITIONAL criteria, but it doesn't necessarily have to be met.



I see what you are saying but at the same time the conclusion was linked with an "And" and not an "or" so even though it is an additional criteria it is one that should still be met where both terms before/after the "and" must always both be met (as oppose to the conclusion saying "or" . If the conclusion said "or" then I agree that the negation does not do anything because the argument does not commit us to saying, in the "or" case, that the birds must have also told their peers about the humans so perhaps it could be the case that birds never pass their "intel" to their peers because they always just recognize threatening people
 
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Re: Q23 - A scientific study provides evidence that crows

by ErikS659 Thu Nov 30, 2017 8:30 pm

I agree with the other reply. A is not necessary. The stimulus merely states that crows "can" tell other crows. That is, they are able. They don't have to pass it on. It could be that the crows that shrieked are all the same crows who were trapped and released.
 
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Re: Q23 - A scientific study provides evidence that crows

by JasonT877 Thu Mar 29, 2018 10:29 pm

A is the correct answer.

Evidence shows ... crows are capable of recognizing threatening people AND can even pass their concerns to other crows.
The evidence shows that crows have the ability to do BOTH. Therefore, years later the crows dive-bombed while recognizing threatening people. To show that the original crows passed their concerns, it’s necessary to assume that there were crows who were not in the original crop and were told of the threat.
 
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Re: Q23 - A scientific study provides evidence that crows

by DPCTE4325 Tue Nov 13, 2018 6:59 pm

ohthatpatrick wrote:Question Type:
Necessary Assumption

Stimulus Breakdown:
Conclusion: Crows can recognize scary people and tell other crows.
Evidence: Researchers in masks had trapped wild crows and later released them. When people wearing the same masks came back to that area years later, the crows raged on them.

Answer Anticipation:
This is a classic Explanation/Interpretation template:
PREMISE - a curious fact, a statistical change, a correlation
CONCLUSION - someone's explanation for / interpretation of that background fact.

Here, the friend is trying to explain/interpret the fact that when people came back years later in the same masks, the crows went nuts on them. The author interprets this to mean that the original crows who were trapped told other crows about these masked people, and since the crows now recognize these people as a threat, they went on the attack.

Whenever we evaluate this template, we ask two different, though related, questions:
1. Is there some OTHER WAY to explain the background fact (i.e. what ELSE could explain why crows attacked the masked people years later?)
2. How plausible is the AUTHOR'S INTERPRETATION (i.e. can crows actually remember features of human appearance? can crows actually communicate that threat to other crows?)

For Necessary Assumption, I anticipate that we will rule out an ALTERNATE EXPLANATION for why the crows attacked. (Maybe the masks are just scary. Maybe the people were unknowingly getting too close to some crows' nests. Maybe it was just the original crows, and they never "passed their concerns" to other crows)

Correct Answer:
A

Answer Choice Analysis:
(A) Yes, this should work. If you negate it, you get the idea that "all the angry crows were the original crows". That weakens the notion that the original crows "passed their concerns" to other crows. It supplies a different interpretation of the same crow attack.

(B) "ALWAYS" is way too strong to be necessary here.

(C) "MOST" of "ANY" species is way broader than the author needs to assume.

(D) The author doesn't need to assume anything about any other situation. Her argument is just about this scientific study and whether it provides evidence that crows CAN (at least once) do something. And of course "most" = "automatic garbage" 99% of the time on Necessary Assumption.

(E) The author thinks that crows are possibly capable of recognizing threatening people. That's it. She didn't commit herself to any specific distinctions about "can't do faces, but CAN do masked vs. unmasked)

Takeaway/Pattern: This question really hinges on people noticing both claims made in the Conclusion. The correct answer, when negated, doesn't attack the idea of recognizing threatening people. It attacks the idea that the crows passed their concerns on to other crows. This study provides no evidence of that unless some of the angry crows were not part of the original crew. We need at least some "new" crows to be attacking if we think this says anything about the ability of crows to tell other ones about danger they've encountered.

#officialexplanation


Hey Patrick,

Using the anti-conclusion method, would your pre-rephrase have been [Given the premises]... the scientific study does NOT provide evidence that crows are capable of recognizing threatening people and does NOT provide evidence that crows are can pass their concerns on to others crows?

If so, wouldn't negated answer choice E wreck the first part of the argument? "Crows cannot distinguish between people who are wearing caveman masks and those who are not". Is E wrong because of the unnecessary second part about recognizing individual faces?

Also, is what the other students are saying true regarding negated answer choice A and how it's still right even though it doesn't address the "capable of recognizing threatening people part?" The conclusion invokes "AND" which means if 1/2 of it fails, then the whole conclusion fails?

Thank you!
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Re: Q23 - A scientific study provides evidence that crows

by ohthatpatrick Sat Nov 24, 2018 12:27 am

When you're arguing against a conclusion, it's just like negating an answer choice:
it is not true that ...

If we say "is is not true that [Crows are capable of A and can even do B]", we don't need to falsify both halves to win.

As long as either A or B is false, then you've proven
"it is not the case that crows can do A and B"

Also, remember that your goal here isn't to pick an answer that, when negated, will REFUTE the conclusion.

Nec Assump = which answer, if negated, most weakens the argument

(E) makes two separate claims, so if you negate it, you're saying "either the first claim is wrong, the second is wrong, or both are wrong". That's already enough of a headache to make me think I'd rather not bust out the negation test.

For (E), it seemed easier to just say head-on that the author was NOT assuming that "crows cannot recognize individual human faces". If anything, the author seems to possibly believe that crows COULD recognize individual human faces. There's nothing in this argument that relates to that one way or another, since all the human faces were masked, but since the author seems to believe in the ability of crows to recognize past threats, I see no way to get from this paragraph that the author thinks "crows CANNOT recognize individual human faces"

Sometimes, an easier way to talk yourself into / out of an answer choice on Necessary Assumption is simply to ask yourself, "Was the author clearly thinking this, in making her argument?"

For (A), I can feel good thinking "yes, the author was clearly thinking that some of these crows were new crows, because that's where the whole line about can even pass their concerns on to other crows would be coming from".