sritamasia wrote:
The corpus callosum—the thick band of nerve fibers connecting the brain’s two hemispheres—of a musician is on average larger than that of a nonmusician. The differences in the size of corpora callosa are particularly striking when adult musicians who began training around the age of seven are compared to adult nonmusicians. Therefore, musical training, particularly when it begins at a young age, causes certain anatomic brain changes.
Which one of the following is an assumption on which the argument depends?
Hello, everyone. It is always fun to practice Logical Reasoning questions, and this one happens to fit well into a CR assumption question mold. The passage itself is easy to follow. The contention is that
musical training, particularly when it begins at a young age, causes certain anatomic brain changes. And why is that? Two premises are offered:
- The corpus callosum... of a musician is on average larger than that of a nonmusician
- The differences in the size... are particularly striking between the corpora callosa of adult musicians who began training around the age of seven and those of adult nonmusicians
How about we dismantle these answer choices, one by one?
Quote:
A. The corpora callosa of musicians, before they started training, do not tend to be larger than those of nonmusicians of the same age.
There is nothing to find fault with here. This
is an assumption that holds the argument together. You can either negate or, if you are like me, you can drag and drop the assumption and place it in between a premise or premises and the conclusion to check for a must-be-true condition.
Premise: The corpora collosa of musicians are on average larger than those of nonmusicians, especially when the musicians started playing around the age of seven.
Assumption: The corpora callosa of musicians, before they started training, do not tend to be larger than those of nonmusicians of the same age.
Conclusion: Therefore, musical training, particularly when it begins at a young age, causes certain anatomic brain changes.
If future musicians were naturally predisposed to possessing larger corpora collosa, then the comparison would be completely baseless. We have found our assumption.
Quote:
B. Musical training late in life does not cause anatomic changes to the brain.
We are not interested in changes from
musical training late in life, since the argument is not based on such changes. As such, this answer choice is nothing more than an irrelevant concern.
Quote:
C. For any two musicians whose training began around the age of seven, their corpora callosa are approximately the same size.
Specificity works against this answer choice. Not only is there no comparison between musicians themselves within the passage, there is also no more in the way of a description between corpora collosa than what may be said about an
average. There can be plenty of variation within an average.
Quote:
D. All musicians have larger corpora callosa than do any nonmusicians.
Watch for overreaching language—
all,
any,
never,
always, and so on—since such language tends to, well, overstate a reasonable case. Again, the passage comments on a tendency between musicians and nonmusicians. A tendency need not hold true in every single case.
Quote:
E. Adult nonmusicians did not participate in activities when they were children that would have stimulated any growth of the corpus callosum.
A reasonable trap answer, but first, we would expect the answer choice to provide information on
musicians, since the argument is based on that group; then, it is not necessary to assume that the nonmusician group had absolutely no experience with
activities... that would have stimulated any growth of the corpus callosum. For all we know, other activities could contribute to such growth, but this particular argument is not based on activities besides learning to play music. Thus, the answer choice falls outside the scope of the argument.
I hope my analysis may prove useful to the community. As always, good luck with your studies.
- Andrew