Self-study
When is it appropriate to choose a potential alternate explanation? I am finding it difficult to find when it is appropriate to choose this AC, or when it is flat out irrelevant. A good example is PT104.S2.P3.Q17
The passage seemed to be focusing on the dark plumage and although I could understand how other characteristics can play a factor- how should I think about when it is appropriate to consider alternative explanations? To my memory, I have chosen this options in previous questions but have been met with the answers being irrelevant.
1
2 comments
Hello!
I definitely see your point. In short, an alternate explanation can the correct answer in a Weaken question if the stimulus makes a causal claim from a mere correlation. If the author assumes X caused Y, pointing out that Z could have actually caused Y perfectly destroys their argument.
Let's look at the experiment in 104.2.3.17. The author assumes that the sole reason behind the birds' differing reactions is the dummies' breast-stripe width. However, what if the dummies also differed in size? If the narrow-striped dummy was massive and the broad-striped dummy was tiny, can the author definitively say the 'breast-stripe width' caused the reaction? No, because the size could be the real reason. Answer (B) successfully weakens the experiment by introducing the possibility of a confounding variable.
I wonder what previous questions you are addressing, but in a Weaken question that involves a correlational-to-causal flaw, then a great way to attack is to provide an alternative cause that no longer allows the author to make an assumption about what the real cause is. To answer your question about when alternate explanations are irrelevant: they are usually only irrelevant if the author never actually makes a causal claim, or if the alternate cause wouldn't actually lead to the outcome we saw.
My best answer to your question would be that alternative explanations are almost always relevant when our goal is to undermine a given explanation. Obviously, they're not always presented as the correct answer choice, but they're almost always worth considering.
In the question you referenced, I think the key is recognizing how the passage develops. The dark plumage discussion is largely set aside as a status signal by the third paragraph. The focus then shifts to breast-stripe width as the strongest indicator of status, and the final paragraph describes an experiment that appears to support that conclusion.
Once we get there, the task becomes fairly straightforward: if the experiment is being used to support the claim that breast-stripe width is the status signal, then a strong underminer will either (1) diminish the importance of breast-stripe width itself or (2) introduce other factors that could explain the observed results.
Answer choice B clearly does the second. If the stuffed birds differed in ways other than breast-stripe width, then we no longer know whether the birds were responding to the stripe width or to one of those other characteristics. The experiment was supposed to isolate stripe width as the explanatory factor, and answer choice B calls that isolation into question.
More generally, when I'm evaluating an alternate explanation answer choice, I don't usually ask, "Is an alternate explanation appropriate here?" I assume it is. Instead, I ask whether the alternate explanation actually provides a plausible path to the same observed result in a way that makes the first explanation unnecessary. If it does, then it deserves very serious consideration.
Hope that helps.
Scott