Logical Reasoning

PT121 · S4 · Q9 A recent study of several

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A recent study of several hundred female physicians showed that their tendency to develop coronary disease was inversely proportional to their dietary intake of two vitamins, folate and B6.

Conclusion (concluded that)

Folate and B6 inhibit the development of heart disease in women.

Evidence (study)

The more folate and B6 a person took, the less likely they were to develop coronary disease.

Evaluate

Whenever we see that the evidence is a study or experiment, we brace ourselves for a causal conclusion. LSAT authors love to look at the results of a study or experiment and then conclude some causal explanation for the data coming out of it. Here, the causal verb in the conclusion is inhibit.

The data from the study is usually a Curious Fact (an asymmetric comparison like a correlation or statistical change or difference between two groups). In this case it was a correlation between higher intake of folate/B6 and lower risk of heart disease.

Here, the author is thinking,

Any time the test presents a correlation between X and Y, and then the author concludes that X causes Y, we are supposed to reflexively consider the two famous Alternate Explanations: - Reverse Cause (maybe Y caused X) - 3rd Factor (maybe something else associated with X is causing Y)

Would it make any sense here to say that ? No, that seems weird.

Is it possible that something else associated with high intake of folate/B6 is the real cause of the lower heart disease risk? Sure!

Goal

We can weaken an Explain Curious Fact type argument one of two ways 1. suggest an Alternate Explanation for the curious fact 2. undermined the Plausibility of the Author's Explanation

So let's look (primarily) for an alternate way to explain the correlation between high intake of folate/B6 and low risk of heart disease.

Or we'll look (secondarily) for an answer that makes it less plausible that consuming folate/B6 lowers women's risk of heart disease.

9.

Which one of the following would, if true, most weaken the researchers' conclusion?

  1. Correct

    The foods that contain significant

    Why this is right

    Here's our Alternate Explanation for why there's a correlation between high intake of folate/B6 and lower risk of heart disease: it's not because the folate/B6 is inhibiting heart disease; rather it's OTHER ingredients in the food that are inhibiting heart disease. Maybe bananas have a lot of folate and B6 in them -- the female doctors who eat lots of bananas are consuming lots of folate and B6, but it's really the potassium in bananas that is inhibiting the heart disease. This is the classic "3rd Factor" style of Alternate Explanation. Something associated with the supposed cause (folate/B6) is the actual cause.

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

    74% picked this

  2. It is very unlikely that

    Unclear Impact

    Folate and B6 are chemical compounds. If they have little to no effect on coronary disease in men, then according to this answer it would be very implausible that they would have any effect on coronary disease in women. So this would weaken, if we knew that these chemical compounds had little to no effect on coronary disease in men. We have no idea whether or not they do. The fact that the conclusion says "these two thing inhibit heart disease in women" doesn't imply that this only works for women. Since we don't know whether folate/B6 seem to have any heart disease effect on men, there's no way to know whether this answer strengthens or weakens.

    2% picked this

  3. Physicians are more likely than

    Irrelevant Comparison

    Irrelevant Comparison: nonphysicians No Impact: know a great deal The study only dealt with physicians. Among physicians, there was a correlation between more intake of folate/B6 and less risk of heart disease. We would need an alternate explanation to explain why the physicians who consume more folate/B6 had lower risk of heart disease than the physicians who consumed less. It's hard to make nonphysicians relevant to this conversation, and we would only care about what they're actually eating, not about what they KNOW about the connection between diet and health.

    2% picked this

  4. The physicians in the study

    Weaker Impact

    This does sound like a methodological weakness of the study, but this wouldn't beat (A) in terms of impact. Since the study relates consumption of folate/B6 to the propensity to develop heart disease. If they turn out to already have heart disease, then they wouldn't be included in this correlation. Or, if the study is measuring folate/B6 intake over the course of a lifetime, then it's fine to have some data points where the physician already developed heart disease. You can still connect that to their folate/B6 intake prior to getting heart disease. It also doesn't matter for the study whether every participant is free of heart conditions (heart condition ? heart disease). There might be some participants with an irregular heartbeat, which would be a heart condition but not heart disease. So while this answer does make us a little nervous about how the data in the study was compiled, there's not a clear enough objection presented by this answer to outdo the objection we get from (A).

    21% picked this

  5. The vitamins folate and B6

    Weaker Impact

    This might seem to make the author's explanation feel a little less plausible: how could intake of folate/B6 make a difference if they're only present in very small amounts in most foods? But there are easy ways to respond to that: - regardless of the tiny amount, the physicians who had MORE folate/B6 had LESS risk of heart disease - the physicians who had more folate/B6 ate those atypical foods that are high in folate/B6 - the physicians who had more folate/B6 intake got those vitamins via supplements, not foods

    2% picked this

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