Logical Reasoning

PT121 · S4 · Q2 Sleep research has demonstrated that

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Sleep research has demonstrated that sleep is characterized by periods of different levels of brain activity.

Conclusion (this shows that)

REM sleep relieves the stresses of waking life.

Evidence

Test subjects who are chronically deprived of REM sleep become irritable during waking life.

Evaluate

Since we're interpreting the results of a study with a Conclusion that makes a causal claim, we can use our Explain Curious Fact mindset.

Curious Fact ... why are the people who are chronically deprived of REM sleep irritable during waking life?

Author's Explanation ... When you get REM sleep, it relieves the stresses of waking life (so you're not as irritable). When you don't get REM sleep, it doesn't relieve the stresses of waking life (so you're irritable)

We're always asking ourselves 1. Could there be an Alternate Explanation for the Curious Fact?

The author is relying on a correlation: people who don't get REM || irritable

We're supposed to ask ourselves about Reverse Causality (maybe irritability makes it hard to have REM sleep) or Third Factor (maybe there's something about their lives, f.e. stressful job / new parents, that is separately preventing them from getting REM sleep and making them irritable).

2. How plausible is the Author's Explanation?

Is there any other evidence that lack of REM is tied to irritability or stress relief? When people start getting REM sleep, do they become less irritable. Is dreaming (which is essentially a code word for REM sleep) tied to stress relief or being less irritable?

Goal

Since we're doing Strengthen, we're looking for an answer to

Rule out an Alternate Explanation or Increase the plausibility of the Author's Explanation

2.

Which one of the following, if true, most strengthens the argument?

  1. Test subjects who are chronically

    Weakens

    This suggests an alternate explanation for the correlation — it's not being deprived of REM sleep that is making people irritable. It's just being deprived of sleep, period. Apparently, this same thing happens when you're denied non-REM sleep too, so sleep is the causal difference-maker, not REM sleep.

    4% picked this

  2. Chronically having bad dreams can

    No Impact

    This is very weakly worded, since it's just saying that "X can lead to Y". It's also discussing an uncommon case (chronically, i.e. constantly, having bad dreams or exciting dreams). It also seems to be irrelevant to the Curious Fact, since we're trying to figure out why people who are chronically deprived of REM sleep (and thus deprived of any dreams) are irritable. Since this answer is about people who have dreams, it's not about the people in our curious fact.

    1% picked this

  3. During times of increased stress,

    Weakens, if anything

    This answer would complicate the author's storyline. She is thinking that when waking life is stressing us, REM sleep will relieve that stress and keep us from being irritable. But this answer is saying that when waking life is stressing us, it will actually prevent us from even having REM sleep.

    10% picked this

  4. Only some people awakened during

    No Impact: reporting dreams

    It makes zero difference to this argument whether people can / can't remember their dreams. We only care about why they're irritable and whether REM sleep-deprivation is the cause.

    0% picked this

  5. Correct

    Other factors being equal, people

    Why this is right

    This adds some plausibility to the conclusion and addresses the new concept, "stress", that only appeared in the conclusion. If REM relieves stress, then the author would expect that people who don't experience REM will have more stress buildup. This answer corroborates that expectation. It doesn't fully prove the author is right, but it adds some plausibility to the story she's weaving.

    Skill tested: Strengthen · how this choice captures the argument's function is the move to repeat next time.

    86% picked this

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