#23 - A scientific study provides evidence that crows are

[lang023]

OK- is it because the question stem says "depends on the assumption"? Obviously, A would support this argument and the argument would depend on it. Maybe I was making it too complicated? haha. ugh!!

[erust2]

As far as not understanding the material.....it will come to you.

But I do feel your pain. After 3 months of studying I was finally hitting my target score. Then my last two practice tests I got the same score as when I took my first practice test cold. LOL.

As far as wrecking the argument, I would say that the negation doesn’t wreck the argument, it just hurts it. “Not always” leaves open the possibility that the birds sometimes do dive. Now, I think the argument can be questioned with the negation B. As in, if they don’t always dive, something may be fishy here.

But, when looking at the A, it’s a much stronger answer then B. Therefore, I immediately forget B and just select to A.

I guess what I am saying is that I think B may have merit as an answer, but A is just so much stronger, that I would have to choose A.

[Alex Bodaken]

erust2,

Thanks for the student-to-student feedback - awesome stuff! The issue with (B) really comes down to the word "always"...the argument depends on the assumption that crows sometimes shriek and dive-bomb those they percieve as threatening, but they don't have to always do this for the answer to be correct (in other words, this response has to be one of the ones they use to those who are threatening, but they could have other ones, too). That's enough to rule (B) out, and as you say, (A) is simply a stronger answer anyway.

Best,
Alex

[erust2]

Thanks so much for the update!

[lang023]

Thank you, Alex! It finally clicked!!

[harvoolio]

Is the point about (D) that negating the choice strengthens, instead of destroys, the argument so it cannot be the answer?

So answer choice (D) would have been a good answer for a question on how to weaken the argument by showing effect without cause?

Thanks.

[Adam Tyson]

You got it, harvoolio!

[BostonLawGuy]

I would love some clarity on this question.

I understand that answer choice (A) makes the assumption that crows passed on the information.

But as I see it, although this answer choice closes that one gap it leaves the other one wide open, that the crows can recognize threatening people.

Like (A), answer choice (E) seems to close one gap, yet left the other open.

Specifically, (E) closed the "crows can recognize threatening people" gap and (A) closes the "Crows pass on their concern to other crows." But neither answer choice closed both of assumptions. Are they equally correct in that they both describe one of the necessary assumptions?

Can someone please help me reconcile this apparent discrepancy?

[James Finch]

Hi Boston Law Guy,

You're correct in that (A) does represent a necessary assumption of the argument--that at least some of the dive-bombing crows were ones that weren't trapped, and thus had the threat communicated to them by trapped crows--which if not true, would destroy the argument. It isn't sufficient on its own to make the argument true, but it is necessary to it. We can test that with the Assumption Negation technique:

All the crows that dive-bombed the later cavemen were trapped earlier by the cavemen

We can't say that crows communicated the threat

However, (E) is actually not necessary to the argument, because the premises given in the stimulus tell us about people wearing the same cavemen masks when they trap the crows as when they approach the crows again years later. Whether crows can tell the difference between people wearing masks or not, or whether they can recognize individual faces, is irrelevant: all we know is that they recognized the cavemen masks and reacted to them as a threat, and that we have to fill the gap of "communicating" that threat. This is what (A) accomplishes, while (E) serves only as a red herring.

Hope this clears things up!

[cjv]

I am having problems with negating A, specifically, there are two ways to negate some; "none" or "all not".

when using "none" to negate answer choice A it becomes "none of the crows that shrieked at and dive-bombed people wearing the masks were not among those that had been trapped".

In other words this would mean 0 of the crows that shrieked and dive-bombed were those that were trapped meaning a completely different group of birds shrieked at and dive-bombed people wearing masks. Does this not help the conclusion/argument rather than hurt it? Obviously this assumes the notion that the original birds that were trapped passed the information to a completely different group of birds, but again this is the negation which is supposed to hurt the argument and not help.