to the top

#2 - Sleep research has demonstrated that sleep is

Administrator
PowerScore Staff
PowerScore Staff
 
Posts: 6656
Joined: Wed Feb 02, 2011 4:19 pm
Points: 3,329

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
LSAT Leader
 
Posts: 33
Joined: Fri Mar 24, 2017 9:12 pm
Points: 33

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
PowerScore Staff
PowerScore Staff
 
Posts: 231
Joined: Thu Nov 17, 2016 11:19 pm
Points: 227

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
LSAT Leader
 
Posts: 33
Joined: Fri Mar 24, 2017 9:12 pm
Points: 33

It helped thank you!
T.B.Justin
LSAT Master
 
Posts: 220
Joined: Fri Jun 01, 2018 6:57 pm
Points: 222

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
PowerScore Staff
PowerScore Staff
 
Posts: 280
Joined: Thu Sep 13, 2018 6:38 am
Points: 279

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.