TkNeo wrote:Smoking is a known cause of certain serious health problems, including emphysema and lung cancer. Now, an additional concern can be added to the list of maladies caused by smoking. A recent study surveyed both smokers and nonsmokers, and found that smokers are significantly more anxious and nervous than nonsmokers.
Which of the following is an assumption on which the argument rests?
A. Anxiety and nervousness can lead to serious health problems.
B. Anxiety and nervousness do not make individuals more likely to start smoking.
C. Equivalent numbers of smokers and nonsmokers were surveyed for the study.
D.Smokers are aware of the various health problems attributed to smoking, including lung cancer and emphysema.
E.Smokers who had smoked a cigarette immediately before responding to the survey were more anxious and nervous than smokers who had not smoked for several hours.
OA: B
This is a classic causation argument - very common on the GMAT.
You had trouble identifying the conclusion because it's not explicitly stated, we need to combine the last two sentences:
"Now, an additional concern can be added to the list of maladies
caused by smoking."
and
"..found that smokers are significantly more anxious and nervous than nonsmokers."
So, the author is blaming smoking for the extra anxiety and nervousness. In other words, the author is concluding that the extra anxiety and nervousness found in the survey were caused by smoking.
In every causation argument, the author is making 2 key assumptions:
(1) cause-effect haven't been reversed; and
(2) there are no other causes.
Where the evidence is a correlation, it's often (1) that plays the largest role in finding the correct answer.
Study: smoking = more anxiety
Conclusion: smoking causes anxiety
However, why couldn't it be true that more anxiety is what causes people to start smoking in the first place?
To reach the conclusion that she did, the author has to be assuming that the cause-effect relationship only runs in the direction suggested by the conclusion. In other words, the author has to be assuming that anxiety does NOT lead to smoking: choose (B), a perfect match for our prediction.