LSAT 35 - Section 1 - Question 03

Which one of the following most accurately expresses the main conclusion of the argument?

This is a Main Conclusion question.

More women than men suffer from Alzheimer’s disease–a disease that is most commonly contracted by elderly persons.

More women than men suffer from Alzheimer’s. That seems to be an interesting fact – a phenomenon.

This discrepancy has often been attributed to women’s longer life span…

The next line gives us another person’s position: “this discrepancy,” which is referring to the fact more women than men have Alzheimer’s, is attributed to (or in other words, caused by) women’s longer life span.

Before you keep reading, let’s take time to digest. Alzheimer’s is mainly in older people, and women have more Alzheimer’s than men. One possible explanation for this is the fact that women live longer – so you’d naturally expect more women to have Alzheimer’s, since that’s a disease of older people.

… but this theory may be wrong.

But wait! The author swoops in with “this theory may be wrong.” That’s a disagreement with other people’s position, which means it’s likely to be the author’s conclusion. What does “this” refer to? It’s referring to the hypothesis that the reason there are more women than men with Alzheimer’s is that women live longer. The author’s saying, “No, that’s not the reason.”

Make sure to be precise about translating the author’s conclusion. They’re not saying that Alzheimer’s isn’t found more in women. They’re agreeing that it is found more in women. But they’re disagreeing with the explanation. The author’s saying, “There must be some other reasons besides women living longer that explains why more women than men have Alzheimer’s.” Why should we believe this? Let’s keep reading.

A recent study has shown that prescribing estrogen to women after menopause, when estrogen production in the body decreases, may prevent them from developing the disease. Men’s supply of testosterone may help safeguard them against Alzheimer’s disease because much of it is converted by the body to estrogen, and testosterone levels stay relatively stable into old age.

We’re told about a recent study that has shown that giving estrogen to women after menopause helps prevent them from developing Alzheimer’s. In addition, we know that men’s supply of testosterone can help prevent Alzheimer’s, since testosterone is turned into estrogen as men age. These two points are giving us some evidence that estrogen may be a potential cause of less Alzheimer’s.

That description of estrogen and its potential effect in preventing Alzheimer’s is offered as a premise for why the hypothesis in the first half might be wrong. The reason more women than men have Alzheimer’s might not be women’s longer lifespan, because it could have something to do with estrogen.

Since we’re looking for the Main Conclusion, let’s look for something along the lines of “Women’s longer lifespan might not be the reason there are more women than men who have Alzheimer’s.”

Correct Answer Choice (A) A decrease in estrogen, rather than longer life span, may explain the higher occurrence of Alzheimer’s disease in women relative to men.

This is a good example of how the correct answer to a Main Conclusion Question can bring in some element of the reasoning. We were looking for something that said the longer life span explanation might be wrong. This answer does say that, but also brings in the hypothesis that the author was suggesting might be the true explanation. This ends up being the best answer, because there’s nothing else that simply states that the longer life span explanation might be wrong.

Answer Choice (B) As one gets older, one’s chances of developing Alzheimer’s disease increase.

This answer has nothing to do with the author’s opinion about the longer life span theory, so we can eliminate it. In addition, (B) isn’t supported by the stimulus. We don’t know that there’s an increasing tendency to develop Alzheimer’s. All we know is that Alzheimer’s is most commonly contracted by old people. But maybe the rate of Alzheimer’s just flattens out after a certain age; it doesn’t need to keep increasing.

Answer Choice (C) Women who go through menopause earlier in life than do most other women have an increased risk of Alzheimer’s disease.

Again, we know the conclusion has to do with suggesting the longer life span theory might be wrong. This answer has nothing to do with that. In addition, (C) is not supported by the stimulus. We know that women who go through menopause start producing less estrogen than they did before. But that doesn’t mean the subset of women who go through menopause earlier in life than most others automatically have increased risk of Alzheimer’s. Maybe the people who go through menopause earlier than most others tend to be the ones who start off with the most estrogen production, and so naturally tend to get less Alzheimer’s than most others? We just have no idea what’s true about this group of women.

Answer Choice (D) The conversion of testosterone into estrogen may help safeguard men from Alzheimer’s disease.

This is a tempting answer choice, because it’s something the author agrees with – this was part of the reasoning of the argument. But it was provided as support for the conclusion that the longer life span theory might be wrong. If you picked this answer, then you are saying that the last sentence of the stimulus contains the conclusion. But where would the statement “this theory may be wrong” fit into the argument if you believe the last sentence is the conclusion? It would have no place, because that comment on the longer life span theory being wrong doesn’t help prove anything about estrogen and testosterone. That’s how we can tell the last sentence is not the main conclusion of the argument.

Answer Choice (E) Testosterone is necessary for preventing Alzheimer’s disease in older men.

As with the other wrong answers (B), (C), and (D), this one also doesn’t say anything about how the longer life span theory might be wrong. So it doesn’t capture the author’s conclusion, which was about that theory. And, like (B) and (C), (E) is not supported by the stimulus. We know testosterone “may help safeguard” against Alzheimer’s, but that doesn’t mean it’s necessary to prevent Alzheimer’s in men. Something can be helpful without being necessary.