#23 - A scientific study provides evidence that crows are

[Administrator]

Please post your questions below!

[Tyler]

Hello,

I was between A and C for this one and chose C because I did not believe A, when negated, hurt the argument in any way. If anything, I thought if anything the negated statement would help the argument. My negated version of A was "None of the crows that shrieked at and dive bombed people wearing the masks were among the crows that had been trapped". Can someone let me know what I am missing? Thanks!

[mattnj]

This was sneaky, IMO! I was thinking the assumption was that if crows perceived someone as threatening, they would shriek and dive-bomb. (the "always" in that choice B should have warned me though).

But I guess the correct assumption has to do with the conclusion in the stimulus, which is that crows are capable of passing on their concerns to other crows. For this to be valid, there must be at least some crows that were not in the earlier incident.

Is this the correct way of thinking?

[James Finch]

Hi Tyler and Matt,

This question is a bit tricky, as it requires quickly recognizing the important part of the conclusion and seeing that this assumption question would require a Defender, not Supporter. The conclusion has two parts, that crows can 1) recognize threatening people and 2) pass on this information to other crows.

The evidence for this is the seeming recognition of people in cavemen masks in the same place, years apart; earlier the crows had been trapped by people in masks, and then years later attacked them preemptively. This seems to take care of the recognition issue in the conclusion, but doesn't necessarily support the ability of the crows to pass on that information to other crows; without knowing how long crows live, we don't know that it wasn't the same crows who had been trapped that attacked the people in the masks, which yields a strong prephrase, stronger than most Defender assumption types.

Answer choice (A) gets to this point immediately, adding a premise that at least some of the crows that attacked the masked people hadn't been trapped by them earlier, indicating that they weren't merely recognizing their earlier trappers but warned by other crows. Testing it with the Assumption Negation technique, we negation along the lines of "all the the crows that attacked the masked people had been trapped by the masked people years before" which would serve to negate the part of the stimulus about passing on concerns to other crows (although not the recognition part!).

Answer choice (C) is irrelevant, as it deals with "most birds of any species" while we are only concerned with crows and whether their recognition and ability to pass on their concerns is causing their aggressive behavior towards the masked people.

Hope this helps!

[mattnj]

Thanks James, it does.

[sydnew]

I understand why A is correct but could you explain why D is incorrect? I took it as illustrating they can pass on their concerns.

[James Finch]

Hi Sydnew,

The issue with answer choice (D) is that it's actually providing evidence for the opposite conclusion, implying that crows just hate people in caveman masks generally. (D) is dealing with crows who were never had any interactions with men in caveman masks before then attacking them; the stimulus is attempting to show that crows communicate their memories and knowledge gained from prior experiences onto their offspring or others within their murder. (A flock of crows is technically called a "murder," I don't know why)

We can test (D) against the conclusion, using the Assumption Negation technique:

In places where crows have never been captured, most crows won't shriek at and dive-bomb people wearing caveman masks



Crows aren't capable of recognizing threatening people and cannot pass their concerns on to other crows

So it becomes clear that (D) cannot support the stimulus's conclusion.

Hope this helps!

[lang023]

Hello,

I was wondering if the reason why A was correct is, because the crows did not pass their concerns on to other crows and they just dive bombed them? Also, is it because answer choice A says, "some". I'm not quite sure if I am grasping this correctly.

For this question, I put B. I thought that when negated it would make the most sense and would wreck the argument. How is B not correct? Thank you!

[erust2]

Hi lang023,

I chose B too. But when I do the negation test now, I get “crows don’t always dive bomb.” I think this is the proper negation. So, the improper negation would be “crows never dive bomb.” That is, the proper negation of “always” is “not always.”

So, negating answer B (i.e., crows don’t always dive bomb) still means that they can dive bomb, they just don’t always dive bomb. So, negating answer B does not destroy the stimulus.

I hope I am right about this. Hopefully someone from PowerScore can comment.

[lang023]

Hi Erust2,

Yes, I understand what you are saying, but even though when that statement is negated- "not always" I feel that it could wreck the argument. It's saying that when crows are threatened they dive bomb the threat. This sentence is saying they do "not always" dive bomb...so wouldn't this wreck the argument. I feel that this is the strongest answer choice. I'm still not fully understanding this...