Logical Reasoning

PT142 · S4 · Q18 Pharmacist: A large study of people

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Pharmacist: A large study of people aged 65-81 and suffering from insomnia showed that most of insomnia's symptoms are substantially alleviated by ingesting melatonin, a hormone produced by the pineal gland, which plays a role in the regulation of the body's biological clock.

Conclusion

The recent claims made by manufacturers of melatonin supplements are correct: the pineal gland produces less melatonin as it ages.

Evidence

A large study of people aged 65-81 who suffer from insomnia showed that insomnia's symptoms were greatly alleviated by ingesting melatonin.

Melatonin is a hormone produced by the pineal gland and plays a role in regulating the body's biological clock.

Evaluate

The study seems to show that taking melatonin helps with lessening the symptoms of insomnia. Does that prove that the insomniacs had less melatonin to begin with?

Not really. Ibuprofen might lessen the symptoms of my headache, but that doesn't mean that my headache was caused by having too little ibuprofen in my system.

So one possible answer could be,

Let's say we granted that the insomniacs did have a shortage of melatonin. Does that mean that the pineal gland is producing less melatonin? Not necessarily. We could try to argue that the pineal gland makes just as much as before, but the melatonin goes to the wrong part of the body or gets flushed out of the body more than it used to.

What about the time dimension of the conclusion: . Do we have evidence that the 81 year olds had worse melatonin production than the 65 year olds? How do these compare to younger age groups?

Goal

Look for an answer complaining that , or an answer complaining that .

18.

The pharmacist's argument is flawed in that it

  1. infers from the effect of

    Wrong Flaw

    This is a semi-famous flaw about the distinction between Intent vs. Result (Consequences). The action of taking melatonin had the effect of lessening insomnia's symptoms. Does the author conclude/assume that "the melatonin was taken for the purpose of reducing insomnia's symptoms"? Sure. In this study it seems like that's why they took the melatonin supplements. But we're not mad at the author for thinking this.

    9% picked this

  2. relies on the opinions of

    Wrong Flaw

    This refers to the famous Sampling flaw, in which the sample the author relies on is either too small, unrepresentative, or biased in some way. There aren't really any opinions in this study. The people took melatonin and their symptoms got better. We don't have any evidence that these 65-81 year old's offered their opinions or had any likely reason to offer biased opinions.

    17% picked this

  3. depends on using two different

    Wrong Flaw

    This refers to the famous Equivocation flaw, in which the same word (or, rarely, the same concept) is used two times but in completely different ways. There aren't any terms in this argument that drastically switch in meaning.

    1% picked this

  4. confuses an effect of a

    Always Wrong

    This answer choice is in the realm of the famous Causal Flaw, but this particular version has never been right. When an author looks at a correlation between X and Y and concludes that "X causes Y", she fails to consider the possibility that maybe "Y causes X". But a correct answer would have to say that, "fails to consider that the supposed effect may actually be the cause". We're not allowed to be so certain that we say, "you definitely got it wrong, author. Y causes X." We're just supposed to be saying, "It's premature to be that sure. It might be otherwise." So any time you see a Flaw answer choice saying definitely that the author has confused cause with effect, it is wrong. If an answer choice says "It's possible they confused cause with effect", consider it.

    30% picked this

  5. Correct

    relies on a sample that

    Why this is right

    Say what? This is our best answer? None of these answers would have looked appealing to me (and they're all pulled from the Top 15 Famous Flaws), but this is the one we can most work with. What is the sample? 65-81 year old insomniacs What group does the conclusion speak for? Everyone The conclusion is just saying "the pineal gland produces less melatonin as it ages". Let's concede that the 65-81 year old insomniacs in the study really did have pineal glands that produce less melatonin than usual. Even if that's true, we don't know if the pineal gland is producing less melatonin at age 50 than it did at age 40. We don't know if 65-81 year old's without insomnia have less melatonin coming from their pineal glands than before. This conclusion is making a sweeping Volume Dial claim about all humans, and about the entire timeline of a human life. Given that the conclusion is trying to state a broad truth about the human pineal gland throughout the course of a human life, it is pretty dubious that the argument relies on evidence that only speaks to 65-81 year old insomniacs. They don't seem like a representative sample of the human experience. In writing the initial Evaluate reaction to this argument, I didn't want to pretend like I would have seen this sampling issue coming. Some people definitely will. But this is one of those Flaw questions where there's more than one possible way to complain, and so you may head to the answer choices with your perfectly legitimate complaint but find no answers there that match what you were expecting. At that point, it's time to think very flexibly and just ask yourself questions as you read each answer choice: - is this descriptively true? If not, eliminate. - if so, does it point to a problem with moving from the evidence to the conclusion?

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

    42% picked this

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