October 2011 LSAT Section 3 Question 17

Science writer: The deterioration of cognitive faculties associated with Alzheimer's disease is evidently caused by t...

Ava on February 12, 2020

Approach

Can someone break down their approach to this question and how they arrived at the correct answer? Is this a strengthen or strengthen with sufficient assumption question? Are the premises here diagrammable? I think I got all mixed up over the terminology in this questions. Any help would appreciated. Thanks in advance!

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on February 12, 2020

Hello @shafieiava,

This is a regular strengthen question. In a strengthen w/ sufficient question, we would have to find an assumption that guarantees the the conclusion. In this case, we just need to support the science writer's argument. It is not asking us to find an assumption.

The hard part is determining what that argument is. There is a lot going on here, so how can we isolate the conclusion?

First of all, a claim about cause and effect is usually going to be the conclusion. Often, we will be given a phenomenon, and a scientist will hypothesize the cause of this phenomenon. This hypothesis is the conclusion. The science writer argues that the activities of microglia cause Alzheimer's disease. This is our argument. A key word here is "evidently." So, where is the evidence? It is found in the remainder of the stimulus.

Evidence 1: This deterioration can be slowed by anti-inflammatory drugs like acetylsalicylic acid.
Evidence 2: Alzheimer's patients are unable to eliminate BA from the brain, where it forms deposits. The microglia destroy brain cells when they attack these deposits, which impairs cognitive functions.

The second piece of evidence is pretty strong. It explains how microglia could be the cause of Alzheimer's.

But what do anti-inflammatory drugs have to do with the microglia? How does this support our conclusion? The first piece of evidence is weak.

Answer choice B gives us the link between anti-inflammatories and microglia that we need. We know that acetylsalicylic acid slows the deterioration. If it does so by reducing the production of immune cells, then this supports the idea that the immune cells are the cause!

This is a very tough question. You see how important it is to understand argument structure. The only way to answer this is to identify the conclusion and the premises. Only then can we strengthen the link between the evidence and the argument.