#4 - In Yasukawa’s month-long study of blackbirds, the

[amagari]

I don't fully understand the correct answer to this question. It has something to do with suggesting another correlation or possible cause, but I don't understand the relationships.

1. There is Yakusawa's conclusion

2. There is the critics contention that age is actually the determining factor. So this is the conclusion we are weakening.

Answer: But what is the answer doing? ruling out another possible cause? Comparing apples to oranges? Suggesting a different correlation. I can visualize the difference between what the Critic is assuming and then how the answer choice says "no this is how it really is."

Thanks

[Alex Bodaken]

amagari,

Thanks for the question. This turns out to be a weaken question, in which the correct answer will weaken the critic's conclusion that Yakusawa's conclusion is mistaken. We could rephrase this to say that the correct answer will strengthen the possibility that Yakusawa's conclusion is correct (because we are weakening a criticism of it).

That being said, let's examine the answer choices:

(A) Yasukawa compared the survival chances of two different species of blackbirds, a larger and a smaller species, rather than of different sizes of birds within one species. - This is the credited answer choice. If this is true, then it weaken's the critics argument Yasukawa's research is flawed because of different sizes of the same species...it proves that Yasukawa was comparing two different species, essentially making that criticism irrelevant.

(B) Yasukawa examined blackbirds in their natural habitat rather than in captivity. - This answer choice is irrelevant.

(C) Yasukawa did not compare the survival chances of blackbirds with those of other kinds of birds. - If this were true, it would actually strengthen the critic's argument, which makes this an opposite answer.

(D) Yasukawa noted that the larger blackbirds had more success in fights than did the smaller blackbirds. - This answer choice is irrelevant.

(E) Yasukawa noted that the larger blackbirds tended to have more firmly established social hierarchies than did the smaller blackbirds. - This answer is irrelevant.

Hope that helps!
Alex

[Amitjohn]

Hello,

I am having a bit of trouble seeing why A is the correct answer. I don't see where the critic assumes that Yasukawa is discussing only one species.

So even if Yasukawa was studying two different species of blackbird, couldn't the critics assessment still be valid? Since his statement refers to "blackbirds" in general, not committing him to be asserting a claim about one particular species of blackbird.

[Adam Tyson]

The issue here, Amitjohn, is that the criticism in the stimulus is based on the assumption that the smaller blackbirds are smaller simply because they are younger, and that in time they will grow to be as large as the larger ones in the study. If that assumption is correct, the criticism makes sense - smaller birds don't live longer because they are smaller, but because they are younger.

Answer A challenges that assumption, weakening the force of the criticism by introducing the idea that the smaller birds were not just younger versions of the same species of bird. They were, in fact, a smaller type of bird, and so size, rather than age, could indeed be the cause of the difference. Answer A, if true, supports Yasukawa's conclusion and weakens the criticism of that conclusion.

[nickp18]

Hi Powerscore Team!

I'm a little confused as to how we are supposed to know the blackbirds are of two different species? Nothing is explicitly stated about two different species and the same species has both larger and smaller birds.

Hope this makes sense!

Nick

[Robert Carroll]

Nick,

Because this is a Weaken question, the answer choice can and should be expected to bring in new information. Note the wording of the question: "...if true...", telling us that this is in the Help or Hurt families. The rest of the question makes it clear that this is in the Hurt family specifically, so we know it's a Weaken. Thus, the information in the answer choice doesn't have to come from the stimulus. If answer choice (A) is true, then the criticism would be weakened, so that's our answer.

Robert Carroll

[yycstudent]

Hello,

I am just trying to understand why D is an incorrect answer.
"Yasukawa noted that the larger blackbirds had more success in fights than did the smaller blackbirds." I read it as more success in fights would likely improve chances of survival. Therefore, size in blackbirds does matter - which strengthens Yasukawa's argument (hence, it weakens the critics' argument)

Can you please assist me with walking through how D is considered not relevant?

Thanks!

[Rachael Wilkenfeld]

Hi yycstudent,

Our question stem is very specific here. We are trying to weaken the critic's objection to Yasukawa's study as a misunderstanding of that study. That's a lot to break down, so let's take it step by step.

Yakasawa's study showed that over a month the percentage of smaller birds that survived was higher than the percentage of larger birds that survived. Yakasawa concluded that size was the cause of their survival. Critics responded that the conclusion didn't follow because younger birds are smaller.

Their criticism is that Yakasawa was ignoring a possible alternate cause---youth. We want to weaken that alternate cause by showing that Yakasawa DID NOT overlook youth or need to consider the youth of birds.

Answer choice (A) does that by showing that the small birds were a different species than the large birds, and not, as the critics assumed, younger versions of the larger birds. This weakens the criticism by destroying the underlying assumption.

Answer choice (D) doesn't address the youth issue at all. It gives a reason that larger birds might do better, but that's irrelevant to the idea of overlooking the age of the birds in the study.

Hope that helps!