Logical ReasoningDifficulty: Hard

PT121 S4 Q19 Explanation

Fifty chronic insomniacs participated in

A free, expert breakdown of this official LSAT Logical Reasoning question.

TopicsParadox

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Stimulus

Fifty chronic insomniacs participated in a one-month study conducted at an institute for sleep disorders. Half were given a dose of a new drug and the other half were given a placebo every night before going to bed at the institute. Approximately 80 percent of the participants in each group reported significant relief claimed that their insomnia had returned during the third week of the study.

What this question is testing

Paradox

Your task

Break the argument into its conclusion and evidence, then do exactly what the question stem asks with that structure.

Common trap

Answers that sound relevant to the topic but don't connect to the argument's actual reasoning.

Winning move

Predict what a right answer must do, then test each choice against the conclusion-evidence gap.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
19.

Which one of the following, if true, most helps to explain all the data

Answer choices

  1. Half Explains15% picked this

    Because it is easy to build up a tolerance to the new drug, most people will no longer experience its effects after taking

    When it comes to our two pieces of data, 1) why is the placebo group seeming to get as much relief as the group that got the drug? 2) why are the people who got relief back to normal by the third week? this answer seems to explain #2 -- most people will lose the relief they got from the drug by the third week. But it doesn't explain #1 -- why did the placebo group have the same level of symptom relief during the first two weeks as the drug group did?

  2. Half Explains8% picked this

    The psychological comfort afforded by the belief that one has taken a sleep-promoting drug is enough to prevent

    When it comes to our two pieces of data, 1) why is the placebo group seeming to get as much relief as the group that got the drug? 2) why are the people who got relief back to normal by the third week? this answer seems to explain #1 — most people will get relief from their insomnia by the psychological comfort (i.e. the placebo effect) of just believing they've taken something for their insomnia. Thus, even if the drug does nothing, the placebo group and the drug group will both experience relief. But it does nothing to explain the second piece of data, which is why the relief fades after a couple weeks.

  3. Half Explains2% picked this

    The new drug is very similar in chemical composition to another drug, large doses of which have turned out to

    When it comes to our two pieces of data, 1) why is the placebo group seeming to get as much relief as the group that got the drug? 2) why are the people who got relief back to normal by the third week? this answer seems to explain #1 — the placebo group got as much relief as the drug group because the drug isn't actually effective; thus, the relief that everyone is getting is just psychologically induced placebo effect But it wouldn't explain #2, why the effect fades after a couple weeks.

  4. Correct72% picked this

    Most insomniacs sleep better in a new environment, and the new drug has no effect on an

    Why this is right

    When it comes to our two pieces of data, 1) why is the placebo group seeming to get as much relief as the group that got the drug? 2) why are the people who got relief back to normal by the third week? this explains both. #1 - the drug has no effect, so the placebo group and the drug group have matching experiences because neither the placebo nor the drug is doing anything chemically for them. Meanwhile, most of them are getting some relief from insomnia (the inability to fall asleep) simply by sleeping at this research institute. The new surroundings shake them out of their insomnia rut and allow them to fall asleep (so 80% of them report significant relief from their sleeplessness). #2 - the insomnia comes back by week three for all the people who experienced relief because at that point the institute's sleeping accommodations are no longer a "new environment". The novelty has worn off, the subjects' bodies are now accustomed to falling asleep at the institute, and so they're back to experiencing insomnia as though they were at home (or in any other familiar environment).

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

  5. Explains Neither Too Weak: some3% picked this

    Some insomniacs cannot reliably determine how much sleep they have had or how well

    The only way this answer would have anything to do with explaining either piece of data is if we tried to weave a story that "insomniacs have no idea how much sleep they are or aren't getting, so the 80% and 90% figures from the study are totally detached from reality". However, the word "some" just means at least one, so we can't go from "there is at least one insomniac who can't reliably tell how much sleep they've gotten" to "80% of people from both groups reported similar relief because an identical percentage of each group was just confused about whether things had improved or not. Similarly, 90% of the group who thought they were sleeping more randomly switched to thinking they had reverted back to previous sleeping levels in the third week since they don't really have a good feel one way or the other."

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