LSAT 152 | Section 2 | Logical Reasoning: Q23

LR Question 23 Explanation

QUESTION TEXT: A scientific study provides evidence that crows are capable…

QUESTION TYPE: Necessary Assumption

CONCLUSION: A study suggests crows may be able to recognize threatening humans and tell other crows about them.

REASONING: Researchers wore caveman masks, kidnapped some crows, and released them locally. Years later, crows attacked people wearing the same masks.

ANALYSIS: When you read a question like this, open your mind to any possibilities that flash through your imagination: your brain may be to help you prephrase. Another trick is to ask “what’s another reason the crows may have attacked”.

1. Maybe these were the same crows, and they recognized their earlier attackers. We don’t know how long crows live.
2. Maybe the masks are intrinsically threatening, and the crows would have attacked anyway. Or maybe the humans were in a delicate area, i.e. they went near the crows’ nests.

Answer A is worded strangely, but it’s referring to the first possibility. We have to assume that the crows in question aren’t all the same crows.

___________

1. CORRECT. If this isn’t true, then all of the crows that dive-bombed had earlier been kidnapped by men in caveman masks. So, while the crows may have recognized the masks, there is no evidence they can “pass their concerns on to other crows”.
    
   This is a weirdly worded answer. When you see a strange answer, don’t dismiss it. Only rule out an answer definitively when you can take the time to understand what it means. “Some….were not” negates to “all of them were”.
   Negation: All of the crows that attacked had previously been kidnapped by the researchers in caveman masks.
2. This isn’t necessary. It’s only necessary that crows sometimes will use shrieking and divebombing against a threatening individual. An answer with “always” will rarely be right on a necessary assumption question, because most of the time we don’t care about the tiny difference between “all” and “not all”.
   Negation: 99.99% of the time crows respond to threats with shrieking and divebombing. But a small percentage of the time, the crows are lazy.
3. This talks about other birds watching the crows. But the question is about the crows themselves, not other birds.
4. This weakens the argument if true. We’re looking for something that strengthens the argument if true, and destroys it if negated.
    
   (This weakens it by showing that cavemen masks are intrinsically threatening to crows, and that the past kidnapping had nothing to do with it).
5. This weakens the argument! It says crows can’t recognize human faces. But the conclusion was that crows can recognize faces, so this wrecks the conclusion. (The correct answer will strengthen the conclusion, and wreck the conclusion if negated.)

Recap: The question begins with “A scientific study provides evidence that crows are capable”. It is a Necessary Assumption question. Learn how to master LSAT Necessary questions on the LSAT Logical Reasoning question types page.