Studies of trauma victims suggest that shock brought on by violent or

Question

Studies of trauma victims suggest that shock brought on by violent or life-threatening situations causes damage to the hippocampi, structures in the brain that play a crucial role in learning and memory. Researchers found that in combat veterans suffering from posttraumatic stress symptoms, which include nightmares and vivid flashbacks, the hippocampi were eight percent smaller in volume than in combat veterans who suffered no such symptoms. The researchers concluded that the hippocampi had lost cell mass as a result of trauma.

Which of the following, if true, would most seriously weaken the researchers' conclusion drawn above?

(A) In another study, subjects who had experienced the death of a close relative were found to have no reduction in the volume of their hippocampi when compared to those whose close relatives were all still living.

(B) In the study, the traumatized veterans were compared with other veterans of similar background, body size, and other characteristics that might have a bearing on brain size.

(C) Some individuals are born with hippocampi whose volume is smaller than average, and this reduced volume makes them more susceptible to posttraumatic stress symptoms.

(D) Combat veterans who experience post-traumatic stress symptoms perform significantly worse on tests of verbal memory compared with veterans who suffer no such symptoms.

(E) Further study revealed that veterans who had seen more intense combat and had more severe post-traumatic symptoms exhibited even greater reduction in the volume of their hippocampi.

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Paras96 · Answer

The researchers' conclusion is that the hippocampi had lost cell mass as a result of trauma. To weaken this conclusion, we need to find information that suggests an alternative explanation for the observed reduction in hippocampal volume in combat veterans suffering from posttraumatic stress symptoms. Let's analyze each answer choice:

(A) This statement discusses individuals who experienced the death of a close relative, which is different from combat-related trauma. Since it does not provide any information about combat-related trauma, it does not directly weaken the conclusion.

(B) This statement indicates that the traumatized veterans were compared with other veterans who were similar in background, body size, and other characteristics. This suggests that factors other than trauma were controlled for, making it less likely that the observed reduction in hippocampal volume was solely due to trauma. This weakens the conclusion.

(C) This statement introduces the idea that some individuals are born with smaller hippocampi, which makes them more susceptible to posttraumatic stress symptoms. While this suggests a potential alternative explanation, it doesn't directly weaken the conclusion about cell mass loss due to trauma in the studied veterans.

(D) This statement provides information about the cognitive performance of veterans with post-traumatic stress symptoms compared to those without such symptoms. While it is related to memory, it does not address the physical changes in the hippocampus or the loss of cell mass due to trauma, so it does not directly weaken the conclusion.

(E) This statement indicates that veterans who had more intense combat experiences and more severe post-traumatic symptoms exhibited an even greater reduction in hippocampal volume. This supports the idea that the observed reduction in hippocampal volume is related to trauma and the severity of symptoms, which strengthens rather than weakens the researchers' conclusion.

Therefore, option (B) is the most relevant choice that weakens the researchers' conclusion because it suggests that factors other than trauma may have contributed to the observed reduction in hippocampal volume.

RiyazAhamed · Answer

I think the answer is C. The passage says the reduction in hippocampal volume (and the loss of cell mass) is caused by stress. But, in C, it states the reverse of the causality - that it is not the stress that causes a reduction in hippocampal volume (or the loss of cell mass), but the subjects who experience stress already have smaller hippocampal volume leading them to experience posttraumatic stress symptoms.

Basically, the premise says: that posttraumatic stress causes shrinkage in hippo.
But, C says, the opposite: the shrinkage is the cause of that posttraumatic stress.

Bunuel · Answer

KAPLAN OFFICIAL EXPLANATION

Here we have a cause-and-effect argument presented in the context of a study. The trauma of the vets must have caused the loss of hippocampi cell mass, the doctors conclude, because those with stress symptoms had smaller hippocampi than those without the symptoms. We're looking for something that would weaken the argument, and a classic way of attacking cause-and-effect is illustrated by (C), which points out that the cause and effect could actually be working in reverse— it could be that the symptoms are the result of the small hippocampi, rather than vice versa. This should remind you of Nietzsche's Cornaro example presented a few pages back.  (C) it is.

An 800 test taker knows all the potential weaknesses of a causal argument. When confronted with the proposition that X caused Y, he considers the possibility that Ymay have in fact caused X, that some third factor Z caused both X and Y; or that the two things are merely correlated and thus not causally related at all.

(A) The argument concerns the effects of "violent or life-threatening" events. The death of a close relative is traumatic, of course, but it isn't
"violent or life-threatening," as those terms are used here. So (A) is irrelevant.

(B) and (E) do the opposite of what we're looking for here. The very fact that (B) asserts the similarity among all the veterans studied tends to support, rather than weaken, the study's findings. And (E), if anything, strengthens the argument by cementing the connection between trauma and tiny hippocampi.

An 800 test taker keeps her eye on the ball at all times, and does not carelessly choose a strengthener when asked for a weakener, or vice versa.

(D) omits the main issue—the connection between trauma and hippocampi damage—and hence cannot have any effect on the reasoning.

Studies of trauma victims suggest that shock brought on by violent or

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Studies of trauma victims suggest that shock brought on by violent or

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615 to 715 in 15 Days (Ria's Strategies)

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