Logical ReasoningDifficulty: Medium

PT150 S3 Q18 Explanation

Efforts to get the public to exercise regularly

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

TopicsNecessary Assumption

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Stimulus

Efforts to get the public to exercise regularly, which have emphasized the positive health effects of exercise rather than the dangers of a sedentary lifestyle, have met with little success. In contrast, efforts to curb cigarette smoking, which have emphasized the dangers of smoking rather than the positive health effects of quitting, dangers of a sedentary lifestyle rather than the positive health effects of exercise.

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
18.

Which one of the following is an assumption on which the

Answer choices

  1. Too Strong: as great as12% picked this

    The health risks associated with a sedentary lifestyle are as great as those

    The author doesn't need the health risks to be equally risky when it comes to sedentary lifestyle vs. smoking. The only equivalence the author is assuming is that in both cases (smoking and sloth), it is more effective to emphasize the harm of doing it than it is to emphasize the benefit of not doing it.

  2. Out of Scope: conveying the message5% picked this

    Efforts to get the public to exercise regularly have been largely ineffective at conveying the message that exercise

    The author has already established that campaign that emphasized the benefits of exercise has had little success. It may be because the efforts didn't really convey the message, or it could be that the message was conveyed but people didn't find it particularly persuasive. The author doesn't need to assume one specific causal backstory for why the efforts to emphasize benefits have failed. For the sake of the author's argument, we just need to know "those efforts were not successful, thus these different efforts would probably be more successful".

  3. Too Strong: few are aware2% picked this

    Although most smokers are aware of the dangers of smoking, few are aware of the positive

    Would it weaken the argument at all if we negated this and said, "Hey, author -- most smokers are aware of the positive effects of quitting"? No, it would have no effect. The author would be like, "Sure. Cool. They're aware of the positive effects of quitting. But when we emphasized the dangers of smoking, we've had a lot of success getting people to quit. So let's try that with exercise."

  4. Correct73% picked this

    Efforts to curb cigarette smoking would not be more successful if they emphasized the positive health effects of quitting rather

    Why this is right

    Would it weaken the argument if we said that, "efforts to curb smoking would be more successful if they emphasized the positive effects of quitting"? Yes! The author is supporting her recommendation by saying, "Look how successful anti-smoking efforts have been when they emphasize the dangers of smoking. You exercise advocates should thus try that technique". If we were able to say, "yeah, but those anti-smoking efforts would be even more successful if they emphasized the benefits of quitting. Thus, we exercise advocates should stick with the more effective tactic: emphasizing the positives of a healthy habit seems to be more effective than emphasizing the dangers of an unhealthy habit." It might be even easier to understand the appeal of this answer if we think about the fuller evidence we would have liked to have heard: Our pro-exercise campaigns should try emphasizing the dangers of not exercising. After all, with cigarette smoking, they tried it both ways, and it was more successful when they emphasized dangers than when they emphasized benefits.

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

  5. Too Strong: majority / primary9% picked this

    The majority of people who successfully quit smoking cite health concerns as the primary motivation

    This loaded language is not our friend on Necessary Assumption, because it's too precise to be necessary. This would be a great answer on Strengthen. But if we negate this, we're getting ideas like, "at most 49% of people who quit smoking cite health concerns as the #1 motivation". Maybe 99% of people who quit smoking cite health concerns as their #2 motivation. That's plenty. The author only has to assume that emphasizing danger is more effective than emphasizing benefits. She doesn't need to assume that it is effective with a majority of people. If emphasizing dangers gets 40% of smokers to quit, but emphasizing benefits only gets 30% of smokers to quit, the author's argument still makes sense.

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