LSAT 149 | Section 3 | Logical Reasoning: Q21

LR Question 21 Explanation

QUESTION TEXT: In an experiment, subjects were shown a series of images…

QUESTION TYPE: Must be True

FACTS:

1. Images in an experiment mostly showed at the top of the screen, sometimes at the bottom.
2. People had to guess where the image would appear,
3. People guessed right less than half the time. They said they were judging based on “patterns” in the data.
4. They would have done better to always guess that the images would have always shown up on top.

ANALYSIS: This is a very tricky question with a deceptively simple answer. I’m going to simplify the facts above:

1. The images were mostly at the top
2. People were often wrong and would have done better guessing the images were at the top

Must be true questions are sometimes about identifying something that already seems true. When the subjects guessed wrong, where were they guessing? It must have been the bottom, because the argument says the subjects would have done better guessing at the top.

But….it’s that simple? Can’t we already assume that subjects guessed at the bottom and were wrong, is this really a deduction? Yes, yes, and yes. Since the stimulus didn’t explicitly state where the subjects guessed wrong, it counts as a deduction to state where they must have guessed.

If I say “Anyone who enters that door will be rich” and “some guy just walked through that door”, it’s correct to say “that guy must be rich”, even though it seems damned obvious from what I said.

___________

1. Who knows? The argument actually suggests this answer might be false. We’re told that subjects always based their guesses on perceived patterns.

   So if subjects started guessing at the top, either:

   1. They stopped guessing on perceived patterns, or
   2. They perceived different patterns and thought the images were at the top

   We don’t know which option is true, so this answer is only possible. We need something which must be true.

2. This is waaaaaaaay too general. The author only told us what guessing pattern would work in the experiment. This answer is about guessing in general. We have no idea what kind of guessing patterns work in life in general.
3. This doesn’t follow. It’s possible that there was a pattern, but that it was too subtle for any of the humans to correctly identify while in the study. But if you showed people the data after the fact, and explained how the pattern worked, then people might be convinced, and “reasonably believe” that it existed.
4. CORRECT. This is basically saying “at least one person incorrectly picked the bottom at least once”. Because always picking the top would have been more successful, they must have incorrectly picked the bottom at least once.
    
   Think how little proof you need for this answer to be true. A single instance of someone guessing wrong on the bottom proves this answer. And the stimulus clearly said that people would have got more right guessing at the top than the bottom.
    
   So the bar for proving this answer right is incredibly low. That makes for a good “must be true” answer choice.
5. This isn’t necessarily true. Guessing the top every time would have been more successful, but that isn’t the same as the most rational strategy. Sometimes, using the best information and rationality we have available at the time, the wrong strategy will be the one that seems best.
    
   And besides, this is a scientific study with no payoff. What does it even mean to talk about what’s rational for people to do in such a situation. Why should they even bother to guess right? Why is that more “rational” than not trying.

Recap: The question begins with “In an experiment, subjects were shown a series of images”. It is a Must be True question. Learn how to master LSAT MBT questions on the LSAT Logical Reasoning question types page.