Q14 - In response to office workers' worries

[jardinsouslapluie5]

I understand why (D) is correct.
But, why not (E)?
Job-related stress could be the real cause for the headache, and not the VDT...

[timmydoeslsat]

Answer choice E would not give us a chance to implicate another cause of the headaches rather than the VDTs.

Answer choice E is telling us that the those who regularly use VDTs and those who do not regularly use VDTs have the same amount of job stress. There is no distinction that gives us a good reason to think this could be a cause, as the stress is the same for both groups. Even then, we do have to make a jump from stress to headaches.

[ohthatpatrick]

This is an interesting question because it triggers an experienced LSAT taker to see 2 major patterns: Causality and Surveys.

The causal pattern is, of course, launched by a correlation between:
higher use of VDT || more headaches

and the author thus concludes that the higher use of VDT causes headaches. LSAT would normally weaken this causal argument by pointing us towards another possible cause.

If (E) were worded differently and said that "those who regularly use VDT's tend to have more job-related stress than do those who don't use VDT's", that would be our correct answer.

When it comes to causality, the test sometimes expects you to use common sense to see how some third variable could really be the causal factor that is producing the observed effect.

However, the other major LSAT pattern this question has is that it's an argument that uses a survey as its evidence. The typical way LSAT weakens an argument based on a survey is to give us an answer that makes us think the survey data is skewed, biased, or somehow untrustworthy.

So you don't know whether you're going to get an answer that Weakens the causal pattern or an answer that Weakens the survey as evidence. But (D) does the latter.

===other answers====

A) this is irrelevant and doesn't help us to distinguish between high VDT and low VDT users.

B) this is an irrelevant distinction. Our correlation is simply between "more VDT | more headaches".

C) this strengthens the argument. If using VDT's causes eyestrain (and eyestrain can lead to a headache), then the VDT's are indeed causing headaches.

E) this strengthens by ruling out an alternative cause of headaches (stress)

[nflamel69]

I have a similar question relating to timmy's post, can we really assume that the higher the stress, the more likely we'll experience headache?

[WaltGrace1983]

I have a similar question relating to timmy's post, can we really assume that the higher the stress, the more likely we'll experience headache?

Someone correct me if I am wrong, but I think you are right to see that (higher stress) does not necessarily mean (more headaches). However, this is a weaken question and so we can be slightly looser than a sufficient assumption question. What I mean by that is, while we cannot say that higher stress → more headaches, the (higher stress) would give us another potential cause.

(E) strengthens because it rules out another potential cause. This would help the argument because, if we are saying that (A causes B), and we find out that (C does not cause B), it makes it ever so slightly more likely that (A actually does cause B). This is a slightly difficult concept to understand if one is new to this type of strengthening/weakening thinking. However, I believe it is easier to think about why eliminating an alternate cause strengthens and providing an alternative cause weakens if you think about it in the following way...

Let's assert a causal argument. Let's say, "I am fast because I run everyday." Thus, I am asserting (I run everyday → I am fast).

There are actually a finite number of reasons why I am be fast. Let's say there are one million potential reasons why I am fast: perhaps I ate my vegetables when I was a kid, perhaps my legs are long, perhaps my dad was an olympic athlete, etc.

If you say, "Yea okay, you are fast. Yet this is so NOT because you ate your vegetables. Eating vegetables doesn't make you fast." What did you do here? You just eliminated one potential reason for why I am fast and you therefore made the finite number of reasons why I am fast one less. Instead of one million potential reasons why I am fast, there are now only 999,999. This strengthens the argument that I am fast because I run everyday. This might be an unconventional way to think about it, but it really helped me when I was first starting out with this strengthen/weaken stuff.

If you say, "Yea okay, you are fast. Yet you also have really strong legs from working out on weight lifting machines everyday!" You just gave ANOTHER reason why I could be fast that ISN'T me running everyday. Uh oh. You just weakened my argument because you showed that maybe it is not because I run everyday why I am fast but, instead, it is because I weight lift with my legs!

So you see, we don't have any idea about what effect weight lifting has on speed or what effect eating vegetables has on speed. However, they are potential causes and how you apply/take away those potential causes will strengthen or weaken the argument. I could have weakened the argument by saying, "Yea okay, your fast but you also ride elephants everyday!" Now this wouldn't be the strongest weakener and you wouldn't see something so ridiculous on the LSAT but it still may provide an alternate cause to my speed.