LR Question 2 Explanation
QUESTION TEXT: Anthropologist: One of the distinctive traits of humans…
QUESTION TYPE: Strengthen
CONCLUSION: Cooking probably let us get more calories from less food (and develop our brains).
REASONING: Our ancestors first got large brains around the time they began to use fire. And modern people who eat only raw food have trouble getting enough calories.
ANALYSIS: So far, the question has just given us two correlations: fire/development of brains and raw food/calorie struggle. But those aren’t direct evidence. We can strengthen the argument by showing an actual advantage for cooking.
You may have made an unwarranted assumption on this question. You can’t assume that a raw food diet is a vegan/vegetarian diet. There are, in fact, some people who eat raw meat. And most wild animals eat raw meat. And humans did before fire. While you can use outside knowledge to think about questions, you can’t use it to assume something must be true, unless literally everyone would agree about it.
___________
- This isn’t an advantage for cooked foods. If anything, it shows raw foods are just as calorie dense as cooked foods!
- If you picked this, you may have made the unwarranted assumption that a raw food diet is vegan. But it’s possible to eat raw meat on a raw food diet. Our ancestors certainly did.
This answer also doesn’t address the proper comparison: is it harder to get enough calories from raw vegetables than from raw meat? (You’d need to eat a larger quantity of vegetables, but it might not be harder to do so.) - Like answer A, this shows no difference between raw food and cooked food. This can’t help.
- CORRECT. This is an advantage for cooked food: it’s easier to process. Suppose you need 2,000 calories, and digesting cooked food takes 100 and raw food takes 500. You’d need to eat 2100 cooked calories or 2500 raw calories.
- It’s possible to have domesticated animals but no fire. This says nothing about cooked vs. raw.
More Resources for Strengthen Questions
- Intro Course lesson: This intro course lesson covers Strengthen questions.
- Mastery Seminar lesson: This LR Mastery seminar lesson covers strengthen questions.
Hi Graeme,
I was confused by this one, because the way I read it, D actually contradicts part of the conclusion.
I read the conclusion piece of the stimulus as “One of the distinctive traits of humans is the ability to support a large brain with a small gut, which requires getting more calories from less food. It was likely the development of fire that made this possible.” I read the “requires getting more calories from less food” as part of the conclusion, as it’s states as a requirement within the conclusion statement, and doesn’t support anything else in the paragraph.
Therefore, I read answer D as partially contradicting this conclusion, because it’s a separate explanation – if the body uses more energy in processing raw food, it does not mean that humans are getting less energy from the food. They are expending more energy in the eating/digestion process, which is separate from the energy received from the food.
With this being said, I choose B, which I also was not happy with, but it seemed as though I was picking between two wrong answers. B required some extrapolations/assumptions to be support, but D seemed to directly contradict part of the conclusion.
Can you please let me know your thoughts? Why is a requirement stated within a conclusion not part of the conclusion, or am I reading something wrong?
Thanks a lot,
The actual conclusion is just “It was likely the development of cooking that made this [supporting a big brain with a small gun] possible.”
The first sentence is just background biology. It’s neither part of the reasoning nor the conclusion. A helpful way to distinguish this is to ask:
1. Is this the main point the author is trying to establish? -> Conclusion
2. Is it providing a reason to believe that main point? -> Premise/Reasoning
3. Is it doing neither, and just setting the stage? -> Background
In this argument, the first sentence falls into category 3: it sets up the context but isn’t part of the argument’s logic. The point of the argument isn’t to prove that humans have this trait; that’s taken as given. The reasoning is in the last two sentences, which connect cooking to increased caloric efficiency.
As for D, it doesn’t contradict the conclusion nor the background. It says the body uses more calories to process raw food than cooked food. That means the net calories you get from raw food are lower. Digestion costs count – if you spend more calories breaking the food down, you end up with fewer calories at all. So it’s not a separate mechanism, it’s explaining the exact mechanism for why cooking made it possible to get more calories from less food (i.e. why cooking helped humans develop this ability).
And to the concern that processing raw food doesn’t mean getting fewer calories: the stimulus already states that raw food eaters struggle to get enough calories. So the argument is already committed to the idea that humans extract fewer usable calories from raw food. D provides the mechanisms explaining why.
Hope that helps! Happy to talk through it more if you have further questions.
This is very helpful. Thanks for the in-depth response.
I purchased the textbook and it doesn’t provide any of the questions. Only the answers. Can you tell me where I can find the questions?
Best source is LSAT law hub: lawhub.LSAT.org
That’s the official source from the makers of the LSAT, and you can get the tests in official format there. Hope that helps!