A study comparing a group of chronically depressed individuals with an otherwise matched group of individuals free from depression found significantly more disorders of the immune system among the depressed group. According to the researchers, these results strongly support the hypothesis that mental states influence the body's vulnerability to infection .
which of the following, if true, casts the most serious doubt on the researchers' interpretation of their findings ?
(c) Disorders of the immune system cause many of those individuals who have them to become chronically depressed. (E) A high frequency of infections can stem from an unusually high level of exposure rather than from any disorder of the immune system.
About braveMBA's explain, you want to say a high frequency of infections don't mean the body's vulnerablility to infection, don't you ? It seems a good explain.
E is so wrong. Let me give you a simper example: sleepiness --> loss of concentration; hunger--> loss of concentration; Either of these two is not the basis to dispute the other. In another word, we cannot say that because sleepiness causes loss of concentration, hunger must not cause loss of concentration. Unless there is a exclusivity clause in the argument, such that only one reason cause loss of concentration.
You misundertood E. If E said that the disorder of immune system in this group of people stems from higher level of exposure, it is the right answer.
The conclusion is "Mental states---> vulnerability of immune system". E show us that infections don't stem from disorder of the immune system, this is another story of disorder of the immune system, and has no any relationship with the argument.
