#14 - In response to office workers' worries about the

[Administrator]

Complete Question Explanation

Weaken. The correct answer choice is (D)

Because frequent VDT users suffered from headaches more often than other office workers did, the researchers concluded that VDTs caused the headaches. As with most arguments of this type, a positive correlation between two variables is interpreted to suggest the presence of a causal relationship between them:

• Cause Effect
  
  VDT → Headache

Since we are asked to weaken a causal argument based on the findings of a survey, our job will typically involve showing either that (1) an alternate cause is responsible for the stated effect, or (2) that the data upon which the survey was based is erroneous. In this particular case, maybe excessive VDT use and headache are both the result of a third, unrelated cause, such as working overtime. Alternatively, maybe frequent headaches make people overestimate how much time they spent using VDT, which would undermine the data used to make the causal statement.

Answer choice (A): Even if few office workers participated in regular health programs, it is still entirely possible that VDT caused their headaches. The frequency with which the workers participated in such programs would only impact the likelihood that their headaches would be diagnosed and treated, not their occurrence in general.

Answer choice (B): The severity of the headaches experienced does not undermine the conclusion that they are all caused by VDT. This answer choice is incorrect.

Answer choice (C): At first, this seems like an attractive answer because some students might interpret "eyestrain" as an alternate cause for the workers' headaches. However, since eyestrain was itself caused by VDTs, this answer choice only explains how VDTs cause headaches and thus strengthens the researchers' argument.

Answer choice (D): This is the correct answer choice. If the workers who experienced frequent headaches tend to overestimate how much time they spent using VDTs, then the survey was based on potentially erroneous data, which undermines the validity of the causal claim.

Answer choice (E): The fact that stress is not correlated with the use of VDT does not establish that headaches are not either. Because the analogy assumes a correlation between two conditions that may have nothing in common, this answer choice does not weaken the argument and is incorrect.

[egarcia193]

HI PS,

Im not understanding how exactly D is correct, I dont see how the fact that the office workers may have overestimated the time they spent on VDT's. Makes it less likely that it VDTS are the cause of the headaches, even if they are overestimating the time they use VDTs with their headaches how does it prove that VDTS still arent the cause of the problem ?

[Luke Haqq]

Hi egarcia193!

You write:

even if they are overestimating the time they use VDTs with their headaches how does it prove that VDTS still arent the cause of the problem?

To clarify, this problem doesn't ask us to prove VDTs are not causing headaches. Rather, it's only asking us to weaken the evidence provided by researchers that they do cause headaches.

And the researcher's claim that VDTs cause headaches is based on a survey. What answer (D) does is it functions as a "data attack"--it suggests there's a flaw, bias, or some other error with the data/survey used to support the conclusion. If (D) were true--if it were the case that "Office workers who experienced frequent headaches were more likely than other workers to overestimate how much time they spent using VDTs," then they could not be used to support the argument that VDT use causes headaches. That is, if these people didn't overestimate and it turns out they actually used VDTs the same amount or even worked less than other workers, this would undermine the researcher's conclusion that the survey establishes that VDTs cause headaches. It would undermine it because there would no longer be that control group of people who both (1) use VDTs more frequently than other workers, and (2) experience headaches.

[egarcia193]

Thanks that make so much more sense now realizing that it was an attack on the survey/data itself

[AnnBar]

Hello,

When answering the questions I found myself between C and D. I thought C presented alternative cause and D discredited the data used in the study. I understand the reasoning for which C is incorrect, but am trying to figure out how I can avoid making this mistake int he future.

When we come across an alternate cause answer choice in a weaken question, can one expect the alternate cause to directly influence both the stated "cause" and "effect", rather than just substitute the "effect"? It seems that is what AC c was doing. It was switching out VTD--> headaches for VTD --> eyestrain

Hope that made sense. Thank you,
AB

[Adam Tyson]

Answer C didn't provide an alternate cause so much as an additional effect, AnnBar - the current study shows VDTs to cause headaches while previous studies show them to cause eyestrain. Perhaps that means that the headaches are a secondary, indirect cause (VDT causes eyestrain which in turn causes headaches) or perhaps not (maybe the two things are both caused by VDTs). In any case, additional effects do nothing to a causal claim, and saying that a purported cause may be an indirect cause doesn't weaken the claim that it is, nonetheless, a cause.

For a true alternate cause answer, look for something else being correlated with headaches, the purported effect. Then you would be on to something!