#23 - Biologist: Researchers believe that dogs are the

[Administrator]

Complete Question Explanation

Justify the Conclusion—PR. The correct answer choice is (B)

Your task in this Justify the Conclusion question is to select the answer choice containing a principle
that, once added to the stimulus, shows the conclusion is valid. The biologist’s argument proceeds:

Premise: researchers believe that dogs are the descendants of domesticated wolves that
were bred to be better companions for humans

Premise: recently it has been found that some breeds of dog are much more closely
related genetically to wolves than to most other breeds of dog

Conclusion: so, some dogs are descended from wolves that were domesticated much more
recently than others

Your prephrase is that the statement in the conclusion regarding the comparative recency of
domestication from wolves is brand new information appearing for the first time in the conclusion.
While there was a comparison in the premises regarding genetic relation to wolves, this comparison
is distinct recency of domestication. So, the correct answer will most likely provide a principle that
connects closer genetic relation to wolves to more recent domestication.

The incorrect answer choices will not justify the conclusion, and instead will either have no effect on
the conclusion or could undermine it.

Answer choice (A): This choice does not justify the conclusion, because its terms are not in line with
those from the stimulus, with this principle referring to “most other breeds of dog,” and it places
the more recent descent as the sufficient condition, while in the argument it played the role of the
necessary condition, the fact inferred from the presence of another condition.

Answer choice (B): This is the correct answer choice. This choice contains a rule with the same
terms as the stimulus, and in the proper order, with closer relation as the sufficient condition and
more recent descent as the necessary condition.

Answer choice (C): This choice is incorrect because it refers to “any breed of dog descended from
wolves that were domesticated,” which removes the comparison from the sufficient condition in the
stimulus.

Answer choice (D): This answer choice provides only a statement that “if you see the sufficient
condition is met, then the sufficient condition must be met,” providing information regarding only
one term, the closer relation to wolves.

Answer choice (E): The conditional relationship in this choice has as its sufficient condition the
closeness of relationship between two breeds of dog, rather than the closeness of relationship
between a breed of dog and wolves.

[mkuo]

Hi all,

I fail to see the correct connection between the following two points from the stem:

1. It has recently been found that some breeds of dogs are much more closely related genetically to wolves than to most other breeds of dogs.

2. This shows that some dogs are descended from wolves that were domesticated much more recently than others.

The correct underlying principle (B) If one breed of dog is more closely related to wolves than to another breed of dog, then the former breed of dog has more recent undomesticated wolf ancestor than the latter breed has.

Undomesticated??? I thought the scope here is domesticated wolves. Dogs from domesticated wolves = better companions.

Thanks for the help!

[Nikki Siclunov]

This is a great example of a question where simply "matching" keywords between stimulus and answer choices proves to be a dangerous strategy.

The argument is structured as follows:

Premise: Some breeds of dogs (let's say Huskies) are genetically closer to wolves than to most other breeds of dogs (let's say Poodles).

Conclusion: Huskies are descended from wolves that were domesticated much more recently than other wolves.

The correct principle must connect the premise and the conclusion: we need to establish that if Huskies are genetically closer to wolves than to Poodles, then the wolf ancestors of Huskies were domesticated more recently than were the wolf ancestors of Poodles. Answer choice (B) says exactly the same thing, but in a different way: Huskies have a more recent undomesticated wolf ancestor than do Poodles.

Avoid the temptation to disregard an answer choice simply because it introduces a seemingly out-of-scope term: think carefully about what it says and see if it matches your prephrase before eliminating such an answer!

Hope this helps!

[mkuo]

Hi Nikki,

Thank you very much! It really helped.

[fg6118]

I'm still a little confused by answer b's use of "undomesticated" wolf ancestors. Is the reason that it works that it doesn't matter if the wolf ancestor is wild or not, as long as the connection that the husky is more related to a recent wolf ancestor over the poodle?

Thanks!

[Emily Haney-Caron]

Hello,

Thanks for the question! Actually for this one, domesticated or undomesticated matters a lot. "More recent undomesticated wolf ancestors" here suggests that the wolves in that line were domesticated more recently. That gets us to the conclusion. Does that help clear it up?

[sgd2114]

Hi,

Hoping someone can help with a quick questions on #23:

Is this an Assumption - PR problem? My test evaluation lists this as a Justify - PR, but the stem asks for a principle that "underlies" the argument, not one that allows the argument to be properly drawn.

Thank you!

[Luke Haqq]

Hi sgd2114,

Yes, this is a justify-the-conclusion/principle question. We can break it apart into conditional reasoning:

Researchers believe that dogs are the descendants of domesticated wolves...

P1: dogs descendant of domesticated wolves

It has recently been found that some breeds of dog are much more closely related genetically to wolves than to most other breeds of dog.

P2: more closely related to wolves dogs

We can link P1 and P2:

more closely related to wolves dogs descendant of domesticated wolves

This shows that some dogs are descended from wolves that were domesticated much more recently than others.

Conclusion: dogs descended more recently

Answer (B) allows that conclusion to follow by adding on a link to the beginning of the chain:

descended more recently more closely related to wolves dogs descendant of domesticated wolves

In other words, we can infer:

dogs more closely related to wolves descended more recently

Or,

dogs descended more recently. This is the original conclusion.

To return to your question, an assumption question asks for some premise that is required by the argument. Here, answer (B) isn't something of that sort--rather, it could be considered a principle that "underlies" the argument in the sense that (B) is the only answer choice that would let the conclusion follow from the premises. It's not a necessary assumption of the argument, though, which is what one would look for on assumption-type questions. Here, (B) is one possible principle that allows the conclusion to follow, but there could be other possibilities as well.

[mhsk]

Hi, I had a major difficulty understanding this question because of the word "undomesticated" in Answer Choice B). I, in fact, eliminated this choice fairly quickly because of "undomesticated" since "undomesticated" was not an issue explicitly mentioned in the stimulus. I thought if the word was changed to "domesticated," then Answer Choice B) is surely the right answer.

Doesn't Answer Choice B) requires the assumption that undomesticated wolf ancestors definitely do come before domesticated wolf ancestors? This assumption do seem logically valid, but it was difficult for me to have this assumption when I was reading the answer choices despite the fact that all other choices seemed even more odd than Answer Choice B). Could you verify that my assumption with Answer Choice B) is correct?

Thanks!

-Rachel

[James Finch]

Hi Rachel,

The process the stimulus is describing is taking wild wolves, domesticating them, then selectively breeding them in order to create the dog breeds we have now. I diagrammed that process as:

Undomesticated Wolves Domesticated Wolves Dogs

The existence of this process is our first premise. The next premise is that some breeds of dogs are genetically closer to wolves than they are to other dogs, with no differentiation made between whether the wolves were domesticated or not. This means that for our purposes, both domesticated and undomesticated wolves are genetically identical.

The stimulus concludes from these two premises that dogs that are more similar genetically to wolves thus had wolf ancestors that were domesticated (Undomesticated Wolves Domesticated Wolves) later in time than dogs that are less similar to wolves genetically. So the conclusion is giving a chronological aspect to the process we've been given as our first premise, a chronology that is also absent from the second premise, making it a novel element in our conclusion.

As a Justify question, even one that relies upon a general principle as this does, will still link the novel element in the conclusion (ie the chronology) to the existing premises. Looking at the Answer Choices, this immediately eliminates (C) and (D), as they don't address the time element at all, and (E) serves only to muddy the waters between the second premise and the conclusion, not link them. So we end up between (A) and (B).

(A) is long and confusing, but immediately becomes suspect when I read "may be," as there is no uncertainty in the stimulus. So we can eliminate it on those grounds alone, as Justify questions leave no room for doubt.

(B) is more straightforward, and fits the premises and conclusion together neatly. We're dealing only with those dogs mentioned in the second premise, the ones more closely related to wolves than other dogs, and linking it directly to what the conclusion describes, which is a later domestication of wolf ancestors than another breed of dog.

I hope this clears things up!