Strengthen
Stimulus Breakdown:
Conclusion: What we think of as old-age hearing loss is really long-term exposure to loud noise hearing loss.
Evidence: In remote populations where they have little exposure to loud noise, age-related hearing loss is almost nonexistent.
Answer Anticipation:
This is a pretty strong piece of evidence. If you thought that noise was the causal difference maker in hearing loss, you'd expect that in areas without much noise, you don't see much hearing loss in the elderly.
However, since we're dealing with a remote population, there could be other significant variables: perhaps they have a different diet (and that somehow affects hearing) or perhaps they die at a much younger age (so they don't reach the same old age other civilizations do). Perhaps they still hunt, which makes them actively use their ears to pick up on subtle sounds (maybe that strengthens hearing into old age). We could rule out any of these potential reasons why the remote populations are unfair to compare to typical populations.
More likely, I'd anticipate that there would be positive evidence for the idea that noise is the causal difference maker: i.e., a situation in which where there WAS noise, and thus there was more hearing loss.
Correct Answer:
B
Answer Choice Analysis:
(A) This wouldn't help us assess the cause of the hearing loss.
(B) This looks pretty good. It controls for the potential weirdness of the remote populations. If the ones that come to louder urban areas end up suffering age-related hearing loss, it buttresses the idea that noise is the causal difference maker.
(C) The fact that city people become used to a low level of noise doesn't help us assess whether that aggregate noise is what causes hearing loss in old age.
(D) This is about a downside of having hearing loss, not anything that would help us assess the cause of hearing loss.
(E) This is just letting us know that people are stubborn and stupid.
Without knowing their eventual levels of hearing loss, or lack thereof, this doesn't help us assess the causal connection between noise and hearing loss. Takeaway/Pattern: When you're trying to strengthen a causal hypothesis, the most common type of answers have the form of "when the cause is absent, the effect is absent" (such as in our premise) or the form of "when the cause is present, the effect is present" (such as in our correct answer).
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