#17 - Science writer: The deterioration of cognitive

[Administrator]

Complete Question Explanation

Strengthen—CE. The correct answer choice is (B)

This stimulus can appear intimidating for students who may not be comfortable with science terminology. However, just as in reading comprehension, our focus is not on the exact scientific process described. We do not need any independent knowledge of Alzheimer’s or brain physiology in order to answer the question. We just need to focus on the internal logic of the argument as we would in any other stimulus.

The stimulus begins with the conclusion: The deterioration of cognitive functioning in Alzheimer’s patients is caused by the activities of microglia. The causal reasoning can be diagramed as follows:

• Activities of microglia (cause) Cognitive decline (effect)

The scientist supports the causal relationship by observing that Alzheimer’s patients are unable to eliminate a certain protein from their brain, where it builds up. Apparently, the microglia attack both the harmful deposits, as well as healthy brain cells, which causes the cognitive decline.

It isn't immediately apparent how the premise about acetylsalicylic acid (aka Aspirin) supports the conclusion that the activities of microglia are involved in the cognitive decline of patients suffering from Alzheimer's, which is precisely why answer choice (B) works so well: it connects that premise to the conclusion of the argument!

Answer choice (A): I understand why this seems like an attractive answer choice: it shows that the immune system is the very reason why patients cannot eliminate the protein BA from their brain, where it builds up and causes the microglia to attack the deposits. It's a vicious circle, if you will. However, this does not support the observation that the microglia specifically are responsible for the decline! Remember - the microglia are the brain's immune cells, not the brain's "immune system." We can blame the immune system for the buildup of deposits, but that doesn't establish that the microglia are responsible for attacking those deposits, thus causing cognitive decline.

Answer choice (B): This is the correct answer choice. As mentioned earlier, the statement that certain anti-inflammatory drugs can slow cognitive deterioration had no direct relevance to the conclusion. If answer choice (B) is true, however, it does! If anti-inflammatory drugs both decrease the production of microglia, as stated here, and also help ameliorate the cognitive decline, as stated in the premise, it becomes even more likely that the microglia is involved in this cognitive decline. Answer choice (B) establishes correlates the decrease of microglia with the slowing of cognitive decline, which naturally supports a causal relationship between the two.

Answer choice (C): The stimulus already states that the microglia attack the protein deposits, and thus, we would expect them to also decrease the buildup of protein deposits in the brain. This does not provide additional information to support the argument and is therefore irrelevant.

Answer choice (D): This answer choice actually weakens the argument, because it suggests an alternative cause for the cognitive decline - it's not microglia, it's the protein itself, that causes the decline.

Answer choice (E): Even if microglia are active in patients whose brains have other diseases, we have no reason to suspect that the effects of this activity involve any cognitive decline.

[melissa27]

In this particular question, is answer choice B correct because their reference to "production" can similarly mean "activity?" In other words would I be able to substitute the word "production" in the answer choice to read as "...reduces the activity of immune cells in the brain?"

[Steve Stein]

In that one, the author's conclusion is that Alzheimer's deterioration is apparently caused by the brain's own immune cells. This is based in part on the fact that such deterioration is slowed by the referenced acid.

If, as correct answer choice B provides, that acid reduces the production of the brain's immune cells (and we also know that the acid slows Alzheimer's deterioration), this strengthens the author's conclusion that those immune cells are probably causing that deterioration.

I hope that's helpful--let me know.

~Steve

[jrafert]

I'm confused! my book says "B" is the right answer, not A?

[Steven Palmer]

Hello,

Yes, (B) is the correct answer. Sorry about any confusion!

Steven

[AnnBar]

Hello,

I was not able to find a more in depth explanation of why B is the correct answer so I wanted to check in about my logic. This is a cause and effect-strengthen question. Answer B is correct because it represents NO cause NO effect. Is that correct?

Thank you in advance

[Adam Tyson]

Correct, AnnBar! That's exactly the way to look at answer B. We know that when the acid is present, the deterioration is slowed, so the ultimate effect is lessened. We want to strengthen the claim that the immune cells are the direct cause of that deterioration, so if we can show that the slowed deterioration correlates to less immune cell activity then we can strengthen that causal claim in the way you described. Answer B tells us that the acid reduces immune cell activity, appearing to complete the chain for us. Acid causes less immune cell activity, and the absence of that activity correlates with slowed deterioration - where the direct cause (immune cell activity) is reduced, the effect (deterioration) is also reduced.

Winner! Nice work.

[lsatnoobie]

Complete Question Explanation

Strengthen—CE. The correct answer choice is (B)

This stimulus can appear intimidating for students who may not be comfortable with science terminology. However, just as in reading comprehension, our focus is not on the exact scientific process described. We do not need any independent knowledge of Alzheimer’s or brain physiology in order to answer the question. We just need to focus on the internal logic of the argument as we would in any other stimulus.

The stimulus begins with the conclusion: The deterioration of cognitive functioning in Alzheimer’s patients is caused by the activities of microglia. The causal reasoning can be diagramed as follows:

• Activities of microglia (cause) Cognitive decline (effect)

The scientist supports the causal relationship by observing that Alzheimer’s patients are unable to eliminate a certain protein from their brain, where it builds up. Apparently, the microglia attack both the harmful deposits, as well as healthy brain cells, which causes the cognitive decline.

It isn't immediately apparent how the premise about acetylsalicylic acid (aka Aspirin) supports the conclusion that the activities of microglia are involved in the cognitive decline of patients suffering from Alzheimer's, which is precisely why answer choice (B) works so well: it connects that premise to the conclusion of the argument!

Answer choice (A): I understand why this seems like an attractive answer choice: it shows that the immune system is the very reason why patients cannot eliminate the protein BA from their brain, where it builds up and causes the microglia to attack the deposits. It's a vicious circle, if you will. However, this does not support the observation that the microglia specifically are responsible for the decline! Remember - the microglia are the brain's immune cells, not the brain's "immune system." We can blame the immune system for the buildup of deposits, but that doesn't establish that the microglia are responsible for attacking those deposits, thus causing cognitive decline.

Answer choice (B): This is the correct answer choice. As mentioned earlier, the statement that certain anti-inflammatory drugs can slow cognitive deterioration had no direct relevance to the conclusion. If answer choice (B) is true, however, it does! If anti-inflammatory drugs both decrease the production of microglia, as stated here, and also help ameliorate the cognitive decline, as stated in the premise, it becomes even more likely that the microglia is involved in this cognitive decline. Answer choice (B) establishes correlates the decrease of microglia with the slowing of cognitive decline, which naturally supports a causal relationship between the two.

Answer choice (C): The stimulus already states that the microglia attack the protein deposits, and thus, we would expect them to also decrease the buildup of protein deposits in the brain. This does not provide additional information to support the argument and is therefore irrelevant.

Answer choice (D): This answer choice actually weakens the argument, because it suggests an alternative cause for the cognitive decline - it's not microglia, it's the protein itself, that causes the decline.

Answer choice (E): Even if microglia are active in patients whose brains have other diseases, we have no reason to suspect that the effects of this activity involve any cognitive decline.

I have a disagreement regarding the explanation as to why A is not correct. I understand how A leads to a vicious cycle, but the reason why you discount A is b/c "We can blame the immune system for the buildup of deposits, but that doesn't establish that the microglia are responsible for attacking those deposits, thus causing cognitive decline."

But why can't we establish that the microglia are responsible for attacking those deposits? Isn't that literally the premise itself? "Microglia attack these protein deposits by releasing poisons that destroy surrounding healthy brain cells, thereby IMPAIRING the brain's cognitive functions.

In addition, is A wrong because impairing is not the same as "deteriorating"?

[lsatnoobie]

Correct, AnnBar! That's exactly the way to look at answer B. We know that when the acid is present, the deterioration is slowed, so the ultimate effect is lessened. We want to strengthen the claim that the immune cells are the direct cause of that deterioration, so if we can show that the slowed deterioration correlates to less immune cell activity then we can strengthen that causal claim in the way you described. Answer B tells us that the acid reduces immune cell activity, appearing to complete the chain for us. Acid causes less immune cell activity, and the absence of that activity correlates with slowed deterioration - where the direct cause (immune cell activity) is reduced, the effect (deterioration) is also reduced.

Winner! Nice work.

And I have one more question, sorry! I learned from the LR bible that one way to strengthen a causation is to show (no cause, then no effect). But I thought this technique only applies to the argument itself, ie the conclusion?

But B is a premise. Can we apply this technique to any part of the argument? I feel like this is the first time I’m seeing this.

[Malila Robinson]

Hi Lsatnoobie,
The technique can be applied to any part of the stimulus that contains the causal reasoning. Part may be in the premise and part may be in the conclusion, or the entire causal statement may be in the premises or in the conclusion. The method still works as long as you are focusing on the cause and effect.
Hope that helps!
-Malila