#23 - No one knows what purposes, if any, dreams serve

[Administrator]

Complete Question Explanation

Strengthen—PR. The correct answer choice is (D)

This stimulus deals with a hypothesis regarding the purpose of dreams—to erase “parasitic connections” that would otherwise overload the brain. The spiny anteater is the only mammal that does not have rapid eye movement sleep, during which we have our most vivid dreams. Since the spiny anteater has an uncommonly large brain, the author asserts that this provides partial confirmation of the parasitic connection hypothesis, since that theory also predicts that lack of dreams would necessitate extra memory space.

The question stem requires that we find the principle to which this argument conforms. The correct answer will justify the author’s assertion that the parasitic connection hypothesis has been partially confirmed.

Only correct answer choice (D) provides such a principle: a hypothesis (in this case, the parasitic connection hypothesis) is partially confirmed when a prediction (the need for the non-dreaming to have extra memory space) explains an otherwise unexplained set of facts (the spiny anteater’s unusually large brain).

[ylikate]

can someone explain to me why C is incorrect? I thought it also has merits.

C says - "a hypothesized purpose (to erase) is achieved with the help of the action (dream) and could not be achieved (not erase but stored elsewhere) without that action (dream)"

[Steve Stein]

Hi Kate,

Take a look at the boldness of the claims in answer choice (C): this choice claims that the author has confirmed a hypothesis when it's shown that the theorized purpose is achieved with the help of something, and could not have been achieved without it.

Did the author really show that erasure could not occur without dreaming? Not really. Instead, a single example was provided as very limited support for the hypothesis.

I hope that's helpful! Please let me know whether this is clear--thanks!

~Steve

[Snomen]

Can someone please explain why A is incorrect?

[Rachael Wilkenfeld]

Hi Snoman,

There are a few problems with answer choice (A). First, the conclusion here isn't that it will completely confirm the hypothesis, just that it provides some confirmation. Secondly, the we have no idea about how similar the animals are, or what the relevant respects to be similar would be. The answer choice introduces a lot of side issues that don't fit our stimulus, and we can't say that it's all applicable to situation in the stimulus.

Hope that helps.

[annabelle.swift]

Hi, I'm still having trouble getting rid of A. In regards to Rachael's explanation, A doesn't say "the facts provide TOTAL confirmation." When I read "the facts provide confirmation," I feel like that leaves open the possibility that the facts provide just a little confirmation. For example, when I say "I gave her candy," that doesn't mean that I gave her all of my candy.

Secondly, the fact that we don't know how similar the animals are or what the relevant respects to be similar would be seems irrelevant to me. I feel like if the AC is telling me that there exist animals that are similar in all relevant respects to the spiny anteater, who am I to question how similar those animals really are or if they're similar in the "right" respects?

If there exist species that ARE similar in "all relevant respects" to the particular species in question, then why wouldn't a hypothesis supported by evidence about that particular species also apply to all of those species? We already know that those species are similar in "all relevant respects", regardless of what those respects are.

Thank you for your help!

[Jeff Wren]

Hi Annabelle,

What we are looking for in the correct answer to this question is a principle (a broad rule) that matches the facts occurring in the stimulus, or to be more precise, the facts/details in the stimulus would fit within broader scope of the principle.

In the stimulus, we get a hypothesis that dreams are produced due to the brain erasing "parasitic connections." This hypothesis predicts that any animal that doesn't dream (but still uses memory) would need an extra large memory space. The spiny anteater, the only mammal lacking rapid eye movement (the main sleep stage for dreams) has an unusually large brain. This fact gives some (or partial) confirmation of the hypothesis.

What we want in our correct answer is something along the lines of: a hypothesis getting partially confirmed because the prediction of the hypothesis explains something that otherwise seems odd or unusual.

As far as your interpretation of "confirmation" in Answer A, you'll want to be very careful with this. On the LSAT, every word matters, and the difference between "some confirmation" in the stimulus and "confirmation' in Answer A is a big problem. Without a modifier to lessen the degree of certainty, "confirmation" here means "to establish the truth of something" and is absolute. It's similar to the difference between "This theory has been proven" to "This theory has been partially proven."

Secondly, the fact that we don't know how similar the animal species are in the relevant respects is not only relevant but essential to whether the principle applies to the situation in the stimulus. To be clear, Answer A is NOT stating that there are species similar to the spiny anteater in all relevant respects. Answer A doesn't mention spiny anteaters at all, and there is no reason to assume that this answer would apply to spiny anteaters.

Answer A is a principle (a general rule) that is basically saying:

Facts about one species of animal can provide confirmation for hypotheses about all species IF they are similar in all relevant respects to the particular species in question.

The problem is that since we don't know that spiny anteaters are similar to other species in the relevant respects, then this principle does not apply to the facts given in the stimulus as far as we know.