PrepTest 121, Section 4, Question 2
Sleep research has demonstrated that sleep is characterized(49 more words not shown)
Which one of the following,(6 more words not shown)
- ATest subjects who(12 more words not shown)
- BChronically having bad(13 more words not shown)
- CDuring times of(15 more words not shown)
- DOnly some people(15 more words not shown)
- EOther factors being(15 more words not shown)
Reading the argument
Maybe they're irritable because someone keeps interfering with their sleep.
The study deprives people of REM sleep, and those people become irritable. Before giving REM all the credit, I'd want to know what else the deprivation does. Are they also losing sleep more generally? Could that explain the bad mood?
Then the conclusion changes the subject slightly: REM sleep relieves stress. Being irritable and being stressed aren't automatically the same thing. Someone might be short-tempered from exhaustion without having more stress to relieve. We've observed one outcome and drawn a conclusion about another.
What we’re looking for
To strengthen this, I'd look for evidence connecting the sleep pattern to stress, or helping explain why the irritability tells us something about stress. We need more than the original observation that deprived subjects are unpleasant during the day.
Working the answers
- A
This makes the broader sleep-loss concern harder to dismiss. People also become irritable when deprived of non-REM sleep, so irritability isn't a response unique to losing REM. It doesn't show that REM relieves stress. REM might still help, but A doesn't provide the support we're seeking.
- B
This gives us ways dreaming can cause stress, including pleasant dreams that are exciting. Since the passage places dreams in REM sleep, that isn't evidence for the proposed stress-relieving benefit. We need support for REM reducing stress, not examples of dreams adding to it.
- C
Here stress disrupts REM sleep. The argument is trying to establish an effect in the other direction: REM sleep reduces stress. Those two effects could both occur, but evidence for one doesn't establish the other. C could help explain an association between stress and disrupted sleep without showing that sleep is what reduces the stress.
- D
Remembering a dream isn't the same as having one, and neither is the result we're trying to explain. Whether awakened subjects can report their dreams tells us nothing here about REM's effect on stress.
- ECorrect
Now we have evidence about stress itself: people who normally get less REM sleep tend to experience more stress, with other factors held equal. That fits the idea that REM helps relieve stress.
Notice what changed. We aren't relying solely on irritability in people whose sleep researchers have disrupted. We have a relationship between normal REM duration and the very outcome the conclusion concerns. This doesn't prove the causal claim, but it supplies relevant support and reduces the worry that some other difference between the groups explains the result.
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