LSAT 77, Logical Reasoning I, Q2, LSATHacks

LR Question 2 Explanation, by LSATHacks

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.

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1. This isn’t an advantage for cooked foods. If anything, it shows raw foods are just as calorie dense as cooked foods!
2. 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.)
3. Like answer A, this shows no difference between raw food and cooked food. This can’t help.
4. 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.
5. It’s possible to have domesticated animals but no fire. This says nothing about cooked vs. raw.