PT39.S4.Q4: Why am I so terrible at necessary assumption questions?

Ashley2018-1Ashley2018-1 Alum Member
edited July 2021 in Logical Reasoning 2249 karma

I thought the argument was a causal conclusion because of “increases.” Since the argument goes from correlation to causation, isn’t one of the assumptions that there is a causal relationship between watching TV and obesity among North-American school children? What effect does answer choice B have on the argument?

https://7sage.com/lsat_explanations/lsat-39-section-4-question-04/

Comments

  • McBeck418McBeck418 Member
    500 karma

    The stimulus gives us a correlation (premise) and a conclusion based on that correlation. I think you could read this as it saying interactive tv will cause/correlates with obesity

    This is a necessary assumption question, so it wants you to find an assumption that the argument needs to make in order to be true. I typically read this as if the conclusion is true, what must be true.

    B reinforces the premise by providing another correlation to back up its original assertion that TV viewing correlates with obesity. This might strengthen the argument, but it's not a necessary assumption. B does not have to be true when the conclusion is true. Interactive TV could cause obesity even if watching cable did not.

    D is necessary though. The whole argument relies on the correlation that increased TV viewing increases obesity. If children are not going to watch more TV as a result of interactive TV viewing, then this whole argument falls apart. Therefore, it's necessary to assume D in order to come to the conclusion in the stimulus.

  • Ashley2018-1Ashley2018-1 Alum Member
    edited July 2021 2249 karma

    @McBeck418 said:
    The stimulus gives us a correlation (premise) and a conclusion based on that correlation. I think you could read this as it saying interactive tv will cause/correlates with obesity

    This is a necessary assumption question, so it wants you to find an assumption that the argument needs to make in order to be true. I typically read this as if the conclusion is true, what must be true.

    B reinforces the premise by providing another correlation to back up its original assertion that TV viewing correlates with obesity. This might strengthen the argument, but it's not a necessary assumption. B does not have to be true when the conclusion is true. Interactive TV could cause obesity even if watching cable did not.

    D is necessary though. The whole argument relies on the correlation that increased TV viewing increases obesity. If children are not going to watch more TV as a result of interactive TV viewing, then this whole argument falls apart. Therefore, it's necessary to assume D in order to come to the conclusion in the stimulus.

    So the conclusion...is not causal, but a correlation? what's the point of suggesting that tv correlates with obesity and then concluding that a specific type of tv correlates with obesity?

  • BinghamtonDaveBinghamtonDave Alum Member ⭐ 🍌🍌
    8716 karma

    (B) is incorrect because it is not necessary that cable television has caused the increase of obesity in the relevant group. The stimulus never delineates any boundary between "television watched" and cable television, so it is not necessary for the functioning of the argument for (B) to happen. Meaning if we negate (B) we can still have a functioning argument. In addition, (B) just focuses on the availability ("widely available") of a specific type of television and not whether it is actually watched/viewed, which is the core of our problem.

    For necessary assumption questions we could have several possible assumptions necessary for the functioning of the argument in our anticipation, we are not normally looking to make the argument great, we are looking to prevent it from being bad.

    I hope this helps.
    Best,
    David

  • mesposito886mesposito886 Member
    254 karma

    Hey Ashley, thanks for linking the question (so much easier than when people don't). This is an assumption question, which requires that you find an unstated premise that bridges the premise in the stimulus with its conclusion. I find it helpful to break down the argument into parts:

    Premise 1: There is a strong positive correlation between obesity and the amount of TV watched
    Conclusion: With the arrival of interactive television, obesity among children will increase

    We know from the first premise that there is a relationship between obesity and the amount of TV a child watches: the more obese a child is, the more TV they watch. So if we follow the model that more TV watching leads to more obesity, and the conclusion tells us that interactive TV will lead to increased obesity in children, then we can assume that interactive TV must also lead to more TV watched.

    Premise 1: There is a strong positive correlation between obesity and amount of TV watched
    Answer D: Children will increase the amount of TV they watch with interactive television
    Conclusion: With the arrival of interactive television, obesity among children will increase

  • Ashley2018-1Ashley2018-1 Alum Member
    edited July 2021 2249 karma

    @mesposito886 said:
    Hey Ashley, thanks for linking the question (so much easier than when people don't). This is an assumption question, which requires that you find an unstated premise that bridges the premise in the stimulus with its conclusion. I find it helpful to break down the argument into parts:

    Premise 1: There is a strong positive correlation between obesity and the amount of TV watched
    Conclusion: With the arrival of interactive television, obesity among children will increase

    We know from the first premise that there is a relationship between obesity and the amount of TV a child watches: the more obese a child is, the more TV they watch. So if we follow the model that more TV watching leads to more obesity, and the conclusion tells us that interactive TV will lead to increased obesity in children, then we can assume that interactive TV must also lead to more TV watched.

    Premise 1: There is a strong positive correlation between obesity and amount of TV watched
    Answer D: Children will increase the amount of TV they watch with interactive television
    Conclusion: With the arrival of interactive television, obesity among children will increase

    @BinghamtonDave said:
    (B) is incorrect because it is not necessary that cable television has caused the increase of obesity in the relevant group. The stimulus never delineates any boundary between "television watched" and cable television, so it is not necessary for the functioning of the argument for (B) to happen. Meaning if we negate (B) we can still have a functioning argument. In addition, (B) just focuses on the availability ("widely available") of a specific type of television and not whether it is actually watched/viewed, which is the core of our problem.

    For necessary assumption questions we could have several possible assumptions necessary for the functioning of the argument in our anticipation, we are not normally looking to make the argument great, we are looking to prevent it from being bad.

    I hope this helps.
    Best,
    David

    What if answer choice B had said interactive television rather than cable television? What effect, if any, would that have on the argument? Are we allowed to have an answer choice that, if negated, flat-out rejects the conclusion?

    And isn't the argument also assuming that there is a causal relationship between watching TV and being obese?

  • McBeck418McBeck418 Member
    edited July 2021 500 karma

    It depends on what the question stem wants you to do. A necessary assumption wants you to find the assumption that the conclusion needs in order to be true. in order to know if something needs to be true, you can negate it and see if it breaks the argument/denies the conclusion. In certain circumstances, it’s appropriate for the answer to reject the conclusion.

    For instance, our argument wants us to believe that watching interactive tv will make children more obese. If there is already a baseline of children made obese by watching TV then for that base amount to increase, the amount of TV viewing needs to go up. The argument requires that to be true for it to be valid.

    if we negate that idea, we have interactive TV will not lead to increased TV viewing. Therefore interactive TV will make children more obese. That just doesn’t make sense. By negating the statement, we remove it from the realm of possibility. when the argument can’t function without it, we realise that it is in fact necessary to the arguments validity.

    Even if B were to say interactive TV it still seems to suggest another correlation. We can’t draw causation from correlation.

    A correlation just says that events coincide with each other. So children who watch a lot of tv tend to be obese. That doesn’t prove watching Tv causes obesity. Maybe they eat a lot of junk and drink a lot of soda. Maybe they have a health condition. Just because these two things occur together doesn’t prove one caused the other.

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