Hi, BridgetKa,
Great question, and this is in fact an LR question I have given some thought to since I have reviewed this latest LSAT. In a response to a student comment on our recent LR recap (
http://blog.powerscore.com/lsat/june-20 ... ning-recap), I wrote in reference to this question:
There was a Weaken question that had to do with people's estimation of time spent exercising based on watching a video of *themselves* exercising. The trick was that the credited response involved people who watched a video of their *identical* twin exercising were likely to overestimate their performance.
This kind of apparent bait-and-switch that's actually not we've noted is a rather common ploy on harder LR questions. Having read the PS books, you're probably familiar with the idea of Shell Game problems. This is a situation of a "Shell Game that wasn't": the twin is not enough of an issue to prevent this answer from being the option that *most* weakens this argument.
There are a couple key points at play in this question:
- Note the question task: we must find what, if true, would most weaken the argument (emphasis mine). In other words, given the options available, what would harm the conclusion the most. The credited response might not be great; we might not even like it at all; it might only harm the conclusion a little bit; but if it harms the conclusion the most, then that's what we're stuck with.
- Pay close attention to the precise issue in the conclusion. What's the claim here? What evidence do we have? Why is this evidence insufficient? The credited response will likely be at least connected to a salient flaw in the argument.
Let's zero in on the claim/conclusion: People who watch recordings of themselves exercising exercise on average more than people who do not watch such recordings.
What evidence do we have? These people who watch these videos
self-report this higher than average amount of exercise.
What's the problem here? Do we actually believe them? Is what they say true?
Now consider the task: we wish to harm the likelihood of this conclusion; we wish to find evidence that even though people who watch videos of themselves exercising might claim they exercise more, they actually don't.
Consider the answer choices:
(A): This is irrelevant. The kind of exercise performed is not the issue here. No such distinction is made in the argument, and this does nothing to harm the connection between self-reporting and actual behavior.
(B): If anything, this answer
very slightly strengthens the argument, though it suffers from similar but worse issues than those of the credited response!
(C): This answer requires a couple additional assumptions to make it work. It is the classic "fill-in-the-blanks" incorrect answer choice. In this case, if we knew that those who watched a video of themselves exercising were in fact already highly motivated to exercise, then it wasn't the video that made the difference. Heck, I'd need to be pretty motivated to watch myself run on a treadmill [shudder]. However, note that we must introduce a missing and unwarranted assumption to make this answer work.
(D) This is the credited response. Yes, we are dealing with an identical twin here, but this answer is the only one that directly harms the conclusion and it does so by attacking the most pronounced flaw in this argument, that is, do people accurately self-report their exercise habits? The evidence provided in this answer choice, while qualified somewhat by the "identical twin," does provide some reason to believe that people may not accurately self-report such behavior.
(E) This couch-potato answer sounds even more dull than watching myself on a treadmill. Maybe they all just fell into a stupor watching themselves sitting on a couch. In any event, this answer if anything strengthens the conclusion marginally with its problematic couch-potato/exercise analogy.
I hope this helps!