Logical Reasoning

PT135 · S1 · Q8 The proportion of fat calories

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The proportion of fat calories in the diets of people who read the nutrition labels on food products is significantly lower than it is in the diets of people who do not read nutrition labels.

Conclusion (This shows that)

Reading labels on food products promotes healthful dietary behavior.

Evidence

People who read the labels have a lower proportion of fat calories in their diets than do people who don't read labels.

Evaluate

As we read the first sentence and see it takes the form, People who are X are more likely to be Y than those who aren't we know we're getting a Correlation.

What do LSAT authors do 99% of the time after they present a correlation? They assume that one of those factors is causing the other factor.

Here the author presents a correlation between reading labels on food products and having a lower proportion of fat in their diet.

Does he think that , that , or does he not conclude anything causal?

Oh, he steps in it, just like we thought he would.

His conclusion uses a Causal Verb (x promotes y). So we know he's being too hasty in assuming that one half of this correlation causes the other.

After all, people who own vacation homes are more likely than those who don't to drive a luxury car, but it's not like vacation homes cause you to drive luxury cars or vice versa. Those things are correlated because of an underlying condition: dollar-dollar bills, y'all (i.e. wealth).

Similarly, maybe "Low fat in your diet" and "reading labels on food products" are both symptoms of the same underlying cause: trying to eat healthy.

Maybe if you're put on a diet that is supposed to restrict your fat intake, then you suddenly have reason to start reading food labels carefully to inspect the fat content.

Goal

We want to call out the author's Causal Overconfidence (this is one of the 10 famous flaws). Correlations support the notion that two things might be causally connected, but the author isn't allowed to be so confident that one things causes the other.

We otherwise expect an answer to raise the possibility of an Alternate Explanation for the correlation (such as we just did with someone who is health-conscious or trying to remove fat from their diet).

8.

The reasoning in the argument above is flawed in that the argument

  1. Correct

    illicitly infers a cause from

    Why this is right

    Of all the ways a Flaw question can complain about a Causal flaw, this is the most straightforward and boring. Whenever any Flaw answer choice uses Conclusion / Evidence wording like, "infers X from Y", we know to ask ourselves whether those match up with the Conc / Evid. Did the author conclude something causal? Yes, he said "reading labels causes more healthy dietary behavior". Is the evidence a correlation? Yes, he said "reading labels is correlated with lower % of fat in diet". Is it illicit? Yes. It's wrong to be sure that a correlation signifies a causal relationship between two things. It's fine to mildly state that it may indicate a causal relationship.

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

    81% picked this

  2. relies on a sample that

    Not Sampling

    This answer describes one of the other 10 Famous Flaws, Sampling, in which the author relies on a sample that we are given reason to think is either too small, unrepresentative, biased, or unlikely to have provided accurate answers. This argument doesn't rely on any sample.

    2% picked this

  3. confuses a condition that is

    Not Necessary vs. Sufficient

    This answer describes the most common of the 10 Famous Flaws, Necessary vs. Sufficient, in which the author presents a conditional logic relationship in the premises and then applies that conditional rule in some illegal backwards or negated fashion. Since we don't have any conditional rule in the evidence, this can't possibly be that flaw.

    6% picked this

  4. takes for granted that there

    Not False Choice

    This answer describes a flaw that some people have a name for, but it isn't a super famous one. People call it False Choice, when an author is unnecessarily boxing herself into only two options. In this argument, the author didn't consider any possible alternative explanations. The author simply concluded what he considered to be the explanation.

    3% picked this

  5. draws a conclusion about the

    Not Intent vs. Result

    This answer describes a semi-famous flaw (in the top 15, but not the top 10) we call Intent vs. Result. This flaw is where an author says something like, "Jenny's joke made Sam cry. Thus, Jenny must have wanted Sam to cry." Does this argument draw a conclusion "about the intentions of a group of people"? Nope. The author just draws a conclusion that offers a causal relationship between reading labels on food products and having more healthful dietary behavior.

    8% picked this

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