Logical ReasoningDifficulty: Hard

PT144 S4 Q12 Explanation

Researcher: Research has shown that

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

TopicsNecessary Assumption

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Stimulus

Researcher: Research has shown that inhaling the scent of lavender has measurable physiological effects tending to reduce stress. It is known that intense stress can impair the immune system, making one more susceptible to illness. Therefore, it is likely that the incidence the scent of lavender is reduced by this practice.

What this question is testing

Necessary Assumption

Your task

Find the assumption the argument requires in order for its conclusion to hold.

Common trap

Answers that would help the argument but aren't strictly required (sufficient, not necessary).

Winning move

Negate each choice — the right one breaks the argument when negated.

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

The question
12.

Which one of the following is an assumption that the researcher's

Answer choices

  1. Too Broad: many, if not all3% picked this

    Many, if not all, of the scents that have a tendency to reduce susceptibility to illness do so, at least

    This argument is only about lavender. The author doesn't need to assume anything about other "scents that reduce susceptibility to illness". If we negated this, and it turned out that lavender is the only scent that helps your immune system via reducing stress (other scents help your immune system in some other way), that wouldn't hurt the argument at all.

  2. Correct67% picked this

    Some people who regularly inhale the scent of lavender would otherwise be under enough stress to

    Why this is right

    The argument is trying to make use of this causal chain: Inhale ? stress ? immune system ? less lavender reduced less impaired illness The first sentence well establishes that first arrow. But the second arrow isn't accurate. We only know that intense stress can impair the immune system. The first sentence ends with "reduced stress" and the second one begins with "intense stress", so it feels like the 2nd sentence is picking up whether the 1st one left off, but there's a gap there (most of us don't notice it when we read the argument, so we didn't want to disingenuously include it in our Evaluate write-up). If the people who regularly huff lavender are chilled out hippies who have low or even normal stress levels, then even if they stopped smelling lavender, they still wouldn't have the sort of intense stress that messes up your immune system. Thus the stress reduction afforded by the lavender isn't actually saving their immune system from any dysfunction. If we negate this answer, the "some" (at least one) turns to "none" (zero): None of the people who regularly inhale lavender would otherwise (if they stopped inhaling lavender) be under enough stress to impair their immune system. This would badly crush the argument. Another fun fact --- if we noticed the New Term in the conclusion, "those who regularly inhale the scent of lavender", we could have thought, "The argument didn't tell me anything about that group of people, so the author must be assuming something about them". (B) is the only answer that addresses people who regularly inhale lavender.

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

  3. Out of Scope10% picked this

    At least some people who use the scent of lavender to induce relaxation and reduce stress are no more

    Out of Scope: more susceptible than avg. If we negated this, it would be saying, "All the people who use lavender to reduce stress are more susceptible to illness than average". That doesn't weaken the argument. It almost strengthens it. It sort of makes it seem like when you're really susceptible to illness, you're worried that if you get stressed out it will hurt your already-frail immune system and leave you vulnerable to illness, so you try to do everything you can to reduce stress and protect your immune system. Another way to look at this answer is that it doesn't matter what someone's "susceptibility to illness" level is when they begin inhaling lavender regularly. They could be low / medium / high susceptibility; it doesn't matter. The author doesn't care about their starting point relative to others. The author is only arguing that "whatever susceptibility level they have without lavender is lessened by regularly inhaling lavender".

  4. Too Strong: anyone / primarily16% picked this

    In anyone for whom the scent of lavender reduces susceptibility to illness, it does so

    This argument is only about people who regularly inhale the scent of lavender. There might be some people who only periodically inhale lavender, and it might somehow reduce their susceptibility to illness, though not primarily by reducing stress. The existence of such people doesn't affect the author's argument at all about regular lavender-inhalers. So the author doesn't need to assume anything about these other people, as this answer does. Another way to look at this -- if you negate this, it's saying, "there are some people for whom the scent of lavender reduces their susceptibility to illness, but not primarily by reducing stress". Okay, well (A), it could still be secondarily from reducing stress. Who cares if stress is the #1 reason why it reduces their susceptibility to illness. If it's a reason, then the author's conclusion is true. And (B), as we said before, maybe these "some people" aren't those who regularly inhale lavender.

  5. Too Strong: only4% picked this

    Reduced stress diminishes susceptibility to illness only for people who are under enough stress to impair their immune systems

    If we negate this, it says, "There's at least one person whose stress isn't high enough to impair their immune systems at all, but reducing stress still diminishes their susceptibility to illness". Okay, does the existence of that person hurt the argument? No. That dude might not be someone who regularly inhales the scent of lavender, and it's only people in that latter category that we care about.

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