Laura Damone
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Q23 - Male boto dolphins often carry objects

by Laura Damone Wed Jan 23, 2019 12:58 pm

Question Type:
Match the Reasoning

Stimulus Breakdown:
Conclusion: When male boto dolphins carry weeds or sticks, it is more likely to be a mating display than play behavior. Premises: If it were play behavior, researchers would expect females and juveniles to do it too, but only adult males do it.

Answer Anticipation:
There are a few potentially valid ways of reasoning on the LSAT that everyone should be familiar with, and this is one of them: ruling out alternatives. Look for an answer choice that has this format: "If it were A rather than B, we would expect C, but C doesn't happen. So, it's more likely B than A." Also, take note of the degree of this argument. The conclusion is that one alternative is "more likely" and the premise is about what "we would expect" to be true. Be on the lookout for answers that exceed this moderate degree.

Correct answer:
D

Answer choice analysis:
(A) Illegal negation! That's not a flaw our argument exhibits.

(B) "I expect A. If A, then B. So B is likely." No way. This one doesn't rule out an alternative to make its case.

(C) Wrong: illegal reversal! Our argument doesn't exhibit that flaw.

(D) Here it is, but it's definitely a little different than our original. This argument proceeds "If X, I would expect Y. But Y hasn't happened. So it's probably not X." This is essentially contrapositive reasoning with some softening of the degree. What's different about this one vs. our original is the relationship between the alternatives. In D, the alternatives are limited to just two and we conclude it's probably one of them. In the original argument, the alternatives are just two possibilities among many, and we conclude that one is more likely than the other. In some Match the Reasoning questions, this might be a fatal flaw. But in the absence of any better choice, this is the one we should pick.

(E) "If A, I would expect B. Since A will probably happen, B will probably happen, too." This isn't contrapositive reasoning or ruling out alternatives. This is just a softened application of principle.

Takeaway/Pattern:
The concepts of likelihood and expectation don't really lend themselves to formal diagramming, but that doesn't mean we can't strip the argument of its subject matter and look at it's bare logical bones. Abstract the argument even when diagramming seems like a stretch, and look for the logical features the wrong answers will probably botch. In easier Matching questions (think the one you often see in the first half of the section), you're probably going to get a perfect match. In harder ones (that one in the 20's of almost every section), you need to be more flexible. Sometimes you'll have to pick an answer that has a mismatch or two if that's the best you're offered.

#officialexplanation
Laura Damone
LSAT Content & Curriculum Lead | Manhattan Prep