LR Question 25 Explanation
QUESTION TEXT: Many bird and reptile species use hissing as a threat…
QUESTION TYPE: Paradox
PARADOX:
- Many species use hissing.
- This probably evolved from a common ancestor.
- Back when the hissing would have evolved, no predators could have heard the hissing.
ANALYSIS: On paradox questions, you have to do two things:
- Understand why the situation is confusing.
- Pick an answer that explains the confusion.
Here, the confusion is that predators didn’t have hearing back when the hissing evolved. So a hissing noise wouldn’t have been useful. Why did it evolve? I couldn’t prephrase this. So I kept an open mind and looked for something that explained the evolution of a hissing noise for reasons other than the noise.
Note that you are not looking for an answer that is true. You need to explain the confusion. Most trap answers are true, but explain nothing.
___________
- So? This doesn’t explain why hissing evolved. It adds to the confusion: the ancestor couldn’t hear its own hiss.
- So? This doesn’t show that hissing was useful. The predators couldn’t hear it. It doesn’t matter if the ancestor had 5-7 non-hissing threat devices – those are irrelevant.
- CORRECT. Increasing body side is a well known way for animals to frighten predators. This explains why hissing was still useful even though it couldn’t be heard by predators (because it also increased body size).
It explains why hissing evolved even though the sound itself wasn’t immediately useful. - Hissing cost less energy….but it was still useless! Predators couldn’t hear it. We care about cost and effectiveness. A cheap, useless method is no good.
- This doesn’t explain why hissing developed. This answer could have been correct if it said
“hissing developed to help the ancestor find food” or some other reason unrelated to
predators. But the answer didn’t do that, so it offers no explanation.
More Resources for Paradox Questions
- Intro Course lesson: This intro course lesson covers Paradox questions.
- Mastery Seminar lesson: This LR Mastery seminar lesson covers paradox questions.
Just noticed a small thing in your explanation for answer choice C: Doesn’t the answer choice indicate that it is the hissing that leads to increased body size, rather than, as you write, hissing being the byproduct of increased body size? Thanks for your very helpful explanations!
Assuming that hissing leads to increased body size would be a correlation flaw. It could be another separate mechanism by which the ancestor would increase its body size and as a byproduct, produce the hissing noise.
Edit (July 2025): This is incorrect regarding answer C. The comment above by Nina is, indeed, correct that hissing caused the increased body size. The explanation for answer C has been updated.
I agree with Nina.
It says very clearly that we are supposed to take the answer choices as true, and the choice says that “the production of a hissing sound would have increased the apparent body size” — this directly states that hissing leads to increased body size.
Hi! Yours and Nina’s comments are correct. I have updated the explanation for C to reflect this.
Unlike other ‘warranted’ assumptions that appears in some of the LSAT questions, I think this one was kind of a overstretch. Increasing apparent body size is indeed one of the effective ways to defend against predators, but sometimes having increased body size rather hinders the survival of animals from predators. For example, some animal that is predated by an eagle might be more easily detected by them if they have a larger body.
This would be a good objection if the answer had said “the mechanism to produce hissing causes the animal to appear larger in all contexts, even when not hissing”
But this isn’t a forced size increase. The animal can choose to hiss and grow only when it is valuable. If the animal is in a situation where it wants to hiss, presumably the predator has already found it.
The key to doing this kind of reasoning is to think in real world terms, and be concrete. What scenario are you imagining? A snake faces off against a land predator, hisses, grows, and only then gets spotted by an eagle? That’s vanishingly unlikely, and still probably worth it on average since the snake is only hissing because its life was already in danger.