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In a study examining the neural pathway linking auditory perception to motor skills, brain scans of study participants who were tone-deaf-those unable to differentiate between or produce sounds of various pitches-revealed many fewer fibers on the arcuate fasciculus, the pathway connecting the frontal and temporal lobes, than there were in a control group of non-tone-deaf people. In 90 percent of the tone-deaf participants, researchers could not detect the superior branch of the arcuate fasciculus. The researchers concluded that they had found the anatomical cause of tone deafness.
Which of the following would, if true, indicate a major flaw in the researchers' reasoning?
| Text from Passage | Analysis |
| In a study examining the neural pathway linking auditory perception to motor skills, brain scans of study participants who were tone-deaf-those unable to differentiate between or produce sounds of various pitches-revealed many fewer fibers on the arcuate fasciculus, the pathway connecting the frontal and temporal lobes, than there were in a control group of non-tone-deaf people. |
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| In 90 percent of the tone-deaf participants, researchers could not detect the superior branch of the arcuate fasciculus. |
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| The researchers concluded that they had found the anatomical cause of tone deafness. |
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The argument starts with study findings showing tone-deaf people have fewer nerve fibers in a specific brain pathway. It then adds that most tone-deaf people are completely missing part of this pathway. Finally, it jumps to the conclusion that these brain differences are the cause of tone deafness.
The missing or reduced nerve fibers in the arcuate fasciculus are the anatomical cause of tone deafness.
This is a causal argument that assumes correlation equals causation. The researchers found a brain difference between tone-deaf and normal people, then concluded this difference causes tone deafness. But we don't know if the brain differences cause tone deafness, or if tone deafness causes the brain differences, or if something else causes both.
Misc - This is asking us to find a major flaw in the researchers' reasoning. The researchers are claiming that fewer fibers in the arcuate fasciculus is THE anatomical cause of tone deafness. We need to find what would show their reasoning has a serious problem.
The researchers make a very specific causal claim - they say the reduced fibers in this brain pathway IS the anatomical cause of tone deafness. This is a strong cause-and-effect statement based on their correlation findings.
To find a major flaw, we need to think about what could undermine their causal conclusion. The biggest issues with their reasoning could be: (1) Confusing correlation with causation - maybe the brain differences are a result, not a cause, (2) Alternative explanations they didn't consider, or (3) Problems with how they determined what's normal vs abnormal. We want scenarios that would make us seriously question whether they've actually found THE cause.
This choice points out that self-reported tone deafness doesn't always match clinical tone deafness. While this might be relevant for study methodology, it doesn't directly challenge the researchers' causal reasoning about brain anatomy being the cause of tone deafness. The researchers presumably used clinical definitions in their study, so this doesn't reveal a major flaw in their core logical reasoning.
This choice suggests that being unable to produce matching sounds causes the brain fibers to atrophy and die. This directly challenges the researchers' causal reasoning by proposing the opposite causal direction - instead of fewer fibers causing tone deafness, tone deafness (specifically the inability to produce sounds) causes fewer fibers. If true, this would completely undermine their conclusion that they found the anatomical cause, since the brain differences would be a consequence, not a cause. This represents a major flaw in their reasoning.
The fact that many control group participants had perfect pitch doesn't challenge the researchers' causal reasoning. Having an especially talented control group might affect the magnitude of differences observed, but it doesn't undermine the logic that brain anatomy causes tone deafness. This is more of a study design consideration than a fundamental flaw in reasoning.
If tone-deaf participants' brain fibers showed more activity than the control group, this might seem contradictory at first. However, increased activity in fewer fibers could actually support their conclusion - perhaps the remaining fibers are working harder to compensate. This doesn't reveal a major flaw in their causal reasoning.
Similar performance on gross-motor skills between groups doesn't challenge the researchers' reasoning about tone deafness and brain anatomy. The study specifically focused on auditory perception, not general motor skills, so this information doesn't reveal any logical flaw in their conclusion about the anatomical cause of tone deafness.