Q23 - Doctors in Britain have long suspected

[WaltGrace1983]

This is a weaken EXCEPT so we are looking for four answer choices that weaken and one that strengthens/does nothing.

Psychological tests given in Britain to people with heart pain/digestive distress confirm a relationship between (glasses) and ((depression) or (hypochondria))
→
Because person has (depression) or (hypochondria), they wear (glasses).

This is your typical correlation/causation issue. Just because there is a correlation between (glasses) and (hypochondria)/(depression) does not mean that one caused the other. I can instead show that something else caused both, that G caused (H or D), or that there is an alternative explanation. In addition, this question hinges on a survey of psychological testing to people who are both in Britain and complain of heart pain. That is a really narrow population of people and so I could probably show why that survey isn't representative too.

(A) Alternate Explanation. While the argument says that (H or D) → G, this answer choice says that the absence of the (cause) can bring about the (effect). In other words, ~(H or D) → G. This is a typical weakener.

(B) Not really sure how this relates to the argument. This is talking about the right people, those with D or H, but it doesn't relate to glasses at all. It just says that these people should be given testing. Okay but not really relevant - this is probably correct.

(C) Refutes the Test. This shows that the test was not representative. It might even imply that there is an alternate explanation to the glasses wearing: the "quality of light."

(D) This one seems a bit off the mark as well but it DOES seem to weaken much more than (B) ever would. This may provide an alternative explanation to the glasses wearing: fashion. It also could be saying that the test is not representative because the test forgets that a particular fashion (glasses wearing, perhaps?) is more in style in Britain. Either way, this is extremely weak but it does seem to be a better answer than (B). Maybe someone will chime in with more analysis?

(E) This actually refutes a bigger correlation. We already knew that this test was only given to people with heart pain or digestive problems. However, (E) is saying that - when we look at people without those symptoms - there was NO correlation. Hmm....maybe it was actually the heart pain/digestive problems that caused it?! Either way, (E) basically says that the test wasn't representative by refuting a further "test" of a bigger population of people.

So (B) is the best answer of all of them but (D) is incredibly weak. What do you guys think?

[christine.defenbaugh]

Some excellent analysis here, WaltGrace1983!

Before I address (D), some food for thought on causation:

While this argument is absolutely pulling the classic LSAT hat trick of causation/correlation switcheroo, there's also something more insidious happening in the conclusion. Notice how the conclusion says that WHEN tinted glasses are worn it IS because of depression/hypochondria?

This conclusion is not only making a generic causal claim, it's claim that depression/hypochondra is the only possible reason ever for wearing tinted glasses. Even if we WERE to establish that D/H caused a greater tendency toward tinted glasses, claiming that it's the only possible cause would still be a bridge too far.

Thus, any point raised that could show some existing alternate cause of wearing tinted glasses would be enough to weaken this argument!

While (A) hands us this existing alternate cause on a silver platter ("some people wear tinted glasses ...because..."), (D) opens up a very similar door. If fashions differ with respect to tinted glasses, that means that at least some people, somewhere must wear tinted glasses for fashion. If NO ONE did, then how could "fashions differ"?!

So it's actually telling us fairly directly that some people do, in fact, wear tinted glasses because of fashion. This is a great existing alternate cause!

Both (B) and (E) offer a hint of a potential alternate cause, but as you point out, they more importantly call into question the correlation itself by highlighting the limitations of the correlation information we have (Britain and specific ailments).

Keep up the great work!