#2 - Sleep research has demonstrated that sleep is

[Administrator]

Complete Question Explanation

Strengthen-CE. The correct answer choice is (E)

Because those who are deprived of REM sleep become more irritable, the author concludes that REM sleep relieves stress (the first two sentences in the stimulus are largely inconsequential to understanding this argument). You should immediately notice the strong causal element of the conclusion:

• Cause Effect
  
  Premise: No REM → Increased stress
  
  Conclusion: REM → Stress relief

As always, think about what's wrong with this reasoning first: what else could be causing the test subjects who are chronically deprived of REM sleep to be irritable? Maybe it is the chronic lack of sleep, having nothing to do with REM per se? Perhaps being disturbed while sleeping can itself lead to increased irritability. To strengthen the argument, in turn, try to find an answer choice that eliminates at least one of these alternate causes.

Answer choice (A): This answer does the exact opposite of what is needed: it weakens the argument by suggesting an alternate cause (general lack of sleep) for the stated effect (irritability). This answer choice is incorrect.

Answer choice (B): This answer choice is entirely irrelevant to strengthening the argument. If anything, it might suggest that REM (which is when people dream) can itself sometimes cause stress, which would weaken the conclusion.

Answer choice (C): By implying the reverse causal connection between REM and stress (stress causes disturbance in REM sleep, not the other way around), this answer choice weakens the argument and is therefore incorrect.

Answer choice (D): Remembering one's dream is inconsequential to the author's argument.

Answer choice (E): This is the correct answer choice. If normally experienced shorter periods of REM sleep are correlated with increased stress, this eliminates some of the alternate causes for increased stress among the test subjects, such as general sleep disturbance and chronic deprivation.

[AnnBar]

Hello,

Could you clarify how answer choice A suggests and alternative cause? It mentions: "test subjects who are chronically deprives of Non-REM sleep...
How is it that "deprives of Non-REM sleep = general lack of sleep?

Thank you,
AB

[Kristina Moen]

Hi Ann,

The test subjects in the premise were deprives of REM sleep and became irritable. The researcher concluded "This shows that REM sleep relieves the stresses of waking life." But what if it has nothing to do with REM sleep at all? What if the test subjects were just irritable because they didn't get enough sleep? Answer choice (A) says "Test subjects who are chronically deprived of non-REM sleep also become irritable during waking life," but it could also have said "Test subjects who are chronically deprived of [other type of] sleep also become irritable during waking life." Then maybe it's not the lack of REM sleep specifically that causes irritability, but lack of sleep in general.

Here's a somewhat analogous argument:
"People deprived of wheat became irritable, so wheat relieves stress." But knowing that "People deprived of sugar [or any non-wheat food] became irritable" weakens that argument because maybe it was the lack of food overall that caused irritability and had nothing to do with the wheat product specifically.

Hope this helps!

[AnnBar]

It helped thank you!

[T.B.Justin]

I was looking at justifying E as correct in this light:

The answer choice reads, "Other factors being equal, people who normally have shorter periods of REM sleep tend to experience more stress."

If the people that are experiencing shorter (deprived) periods of REM sleep tend to observe more stress, they cannot be getting the normal duration of REM sleep required to relieve stress in waking life, so they are getting some REM sleep just not enough to relieve stress in waking life..


When I went through this problem I correctly identified that the first four answer choices as incorrect, yet once I read E I was like huh what this doesn't make sense to me! And went back through and chose an incorrect answer (A).

Appreciate any help if someone can spot what is going on with my logic here.

[Brook Miscoski]

Justin,

The stimulus delivers the causal conclusion that REM sleep relieves stress. One of the standard ways of strengthening a causal conclusion is to eliminate other potential causes. Answer choice (E) holds "other factors...equal," thus eliminating other factors as a cause. (E) is correct because it is one of the standard ways of strengthening a causal argument on the LSAT.

[teddykim100]

Hello,

can anyone explain how the premise "Test subjects who are chronically deprived of REM sleep become irritable during waking life" is a correlative/causal relationship?

Isn't "become" a strong enough word to establish certainty, and therefore for us to say that "If you are chronically deprived of REM sleep, you are found to be irritable during waking life"?

[Adam Tyson]

The premise establishes a correlation, teddykim100, but nothing causal. The causal claim comes in the conclusion, when the author says that REM sleep "relieves the stresses." That's an indication that the first thing is making the second thing happen, while the premise was just telling us that these two things go together. And yes, the premise is 100% certain, because the author doesn't soften it by saying "some test subjects" or "many test subjects" or "most test subjects," nor did they say that they "can become irritable." But even though it's a statement made with certainty, it's still just establishing a correlation.

[teddykim100]

Hi Adam,

I guess what I meant was, doesn't the premise state a causal relationship by saying "x becomes y"?

Or is to become something not indicative of a causal relationship?

[Luke Haqq]

Hi teddykim100!

It certainly seems like the word "becomes" could often denote a causal relationship. But it may not always be clear what exactly the causal relationship is.

For example, suppose we had a statement like "People who take this pill become angry." Is there an active substance in the pill that makes people angry? Might it be a placebo and they are making themselves angry? Or might there be something with the study design or how the pill was administered that makes them angry? In short, that seems to be example in which people who do X then become Y, but it's not necessarily clear that X caused Y.