Logical Reasoning

PT145 · S2 · Q2 Anthropologist: One of the

A free, expert breakdown of this official LSAT Logical Reasoning question.

  • Save & drill this skill — build targeted practice sets from questions like this one

  • Video walkthroughs — watch every question solved step by step

  • 81 official LSATs — as questions, timed sections & full-length tests

Start practicing free

Anthropologist: 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.

Conclusion

It was likely the development of cooking that made it possible for humans to support a large brain with a small gut.

Evidence

Supporting a large brain with a small gut requires getting more calories from less food.

Our ancestors developed large brains around the time that they began to control fire.

Today, people who choose to eat only raw food have difficulty getting enough calories.

Evaluate

The conclusion is a causal explanation: cooking made it possible for us to have big brains and small guts.

The first piece of evidence is a conditional relationship: Big brain + small gut requires more calories from less food.

The second piece of evidence is a temporal correlation: Big brains and controlling fire (which we can pretty reasonably infer is a precondition for cooking) happened around the same time.

The last piece of evidence is a control group: those who don't cook food don't get enough calories. But....enough calories for what exactly? Do the raw foodists really not get enough calories to support their big ol' brains? It doesn't specify, which makes this pretty poor evidence.

Goal

As is the case with all arguments, we can strengthen in a variety of ways. The goal of prediction is not to come up with what the right answer must say, but instead to think through what a right answer might do.

We're given a conditional premise: Big brain + small gut requires more calories from less food.

If we establish that the only way to satisfy that requirement is to cook your food, this argument looks a whole lot better.

2.

Which one of the following, if true, most strengthens the anthropologist's argument?

  1. Cooked foods contain the same

    Weakener

    If this is true, it weakens the argument that we need to cook to get sufficient calories for our big fat brains.

    1% picked this

  2. Raw meat contains more calories

    Irrelevant Comparison

    We need to compare the caloric content of cooked food and raw food in a way that shows that cooked food gives us more calories. This answer compares the caloric content of two different raw foods.

    1% picked this

  3. The human body is able

    Weakener

    Like A, if this is true, it weakens the argument that we need to cook to get sufficient calories for those big juicy brains of ours.

    1% picked this

  4. Correct

    The human body uses more

    Why this is right

    But boy is this one subtle! Our prediction was something that establishes we need to cook to get enough calories for our brains to be so big. That could take many forms, including a comparison of the caloric content of cooked food vs. raw food. But caloric content isn't the only relevant factor. How many of those calories we can actually extract is relevant, which answer choice C alludes to. How many calories we spend on that extraction is also relevant, and that's what makes D correct. If we have to spend more calories to process raw food than we do to process cooked food, that strengthens the argument that you'll end up with more calories overall when you cook. Think of it like profit in sales. The profit is the amount of money you collect on top of what you spent to make the thing you're selling. If you spend less to make the thing, you profit more. Similarly, if you spend fewer calories digesting cooked food, you net more calories when you eat cooked food.

    Skill tested: Strengthen · how this choice captures the argument's function is the move to repeat next time.

    95% picked this

  5. Domesticated plants and animals are

    Irrelevant Comparison

    We need to compare the caloric content of cooked food and raw food in a way that shows that cooked food gives us more calories. This answer compares the caloric content of domesticated vs. wild food.

    1% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill
LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free