neha283 wrote:
Options A,B and D seemed promising to me. I marked D on the basis of reverse causal relationship idea.
Maybe actual GMAT doesn't have such problems but some practice won't hurt.
Experts - could you provide some analysis and help in eliminating some choices?
VeritasKarishma GMATNinjaTIA.
The question is a bit tricky but elimination helps in being confident about (A).
Hospital patients' immune systems grew stronger when the patients viewed comic videos. This indicates that laughter can aid recovery from illness.
But much greater gains in immune system strengthen occurred in the patients whose tendency to laugh was greater to begin with.
Conclusion: Hospital patients with a greater tendency to laugh are helped more in their recovery from illness even when they laugh a little than other patients are helped when they laugh a greater amount.
The conclusion is a bit out there. The argument just says that watching comic videos helps immunity grow. But it helped those people more whose tendency to laugh was more in the beginning (presumably because they laughed more while watching the video).
Then the conclusion confuses us with "if tendency to laugh is high, even if one laughs less than others, one recovers more"
Let's look at options (B) to (E) first:
(B) Fails to address adequately the possibility that the patients whose tendency to laugh was greatest to begin with already had stronger immune systems than the other patients
Definitely not true. We are talking about "gains in immune system". Even if their systems were better to begin with, we need to look at improvement only.
(C) Presumes, without providing justification, that hospital patients have immune systems representative of those of the entire populations
Definitely not true. The argument talks about hospital patients only. It does not conclude about entire population anyway.
(D) Takes for granted that the gains in the immune system strength did not themselves influence the patients' tendency to laugh
Not true. The argument talks about "tendency to laugh was greater to begin with". So the study measured the "tendency to laugh" in the beginning and then saw what kind of improvements were obtained. What happened to their tendency to laugh after gaining immune system strength is irrelevant.
(E) Presumes, without providing justification, that the patients whose tendency to laugh was greatest to begin with recovered from their illnesses more rapidly than the other patients
The argument gives justification : But much greater gains in immune system strengthen occurred in the patients whose tendency to laugh was greater to begin with.
It tells that people whose tendency to laugh was more had greater gains in immune system strength. Hence it does not presume without justification.
Now let's look at (A).
(A) Overlooks the possibility that the patients whose tendency to laugh was greater to begin with laughed more at the comic videos than did the other patients
Correct. We are not given in the argument that people with higher tendency to laugh laughed little. It is logical that those with higher tendency to laugh actually laughed more. But the conclusion overlooks this.
Answer (A)