Toughest LSAT Questions: PrepTest 76, Section 4, Q21

Hey there!

Today we are going to take a look at a question from practice test 76, section 4, number 21.  The content looks at the link between learning chess and seeing an increase in academic achievement.
Got it? Ok!

Before we begin:

This is a tough question. I actually crossed off all the answers. Then I got it down to B and D, hated them, crossed them off and started over.

Let me say that again: I crossed off every answer twice.  This is going to happen to you some day, so I’m going to break down my thought process so you can see how I finally got to the right answer.

I had nearly convinced myself that D was the right answer just because the other answers were wrong, but I couldn’t prove that  D was the right answer, so I couldn’t choose it.

Spoiler. The answer is not D.

I think it’s helpful to go through some of the mistaken thinking I explored as I tried to solve this problem, in case any of it sounds familiar to you.

Causal Argument:

The first thing to notice is that this is a causal question.  That is, two things happen sequentially in time, therefore the argument concludes that the first event CAUSED the second event.

In this argument, two things happen in a row. The first is that a group of children successfully completes a program where they learn to play chess.  Let’s call that EVENT 1.

The second thing that happens is that most of the kids who completed the program go on to show significant improvement in their schoolwork.  Let’s call this EVENT 2.

The final sentence concludes that the skills used in chess are likely to contribute to other kinds of intellectual achievement. In other words, Event 1 CAUSED Event 2

At first glance this seems like a pretty reasonable conclusion, right? The kids learned chess, and then their grades went up, so it was probably the chess skills that helped them ace those tests.  It is so reasonable, that it’s hard to see that this kind of reasoning is often seriously flawed.

Deeper Dive into why causal conclusions are usually wrong:

What if I said to you that the moon was full, (EVENT 1) and that there were a lot of car accidents that night (EVENT 2)?  I’ve given you two facts.  Both the facts are true.

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But then what if I say that the full moon was the CAUSE of the high number of car accidents? I’ve taken two random facts that happened at the same time and I’ve ascribed causality, where maybe all we have is a coincidence.

A causal conclusion on the LSAT requires so many assumptions that it will almost always be flawed.  You can bank on it.

Back to the Question:

In this case, the question is asking us to undermine the conclusion, which is another way of asking us to weaken the conclusion.

How do we weaken conclusions?  We attack the assumptions. Or we provide some data that would suggest that the conclusion isn’t necessarily true.

And when we have a causal conclusion, there are a LOT of assumptions to attack!

Let’s start by listing the assumptions that a causal question requires.

Assumptions required in order for a Causal conclusion to hold:

First, in order for two events to possibly have a causal relationship, then we need to assume that there is no other cause.

Second, the test assumes that every time the cause occurs, the effect occurs. And likewise, every time the effect occurs, it was triggered by the presumed cause.

Third, causal relationships require that if the cause did NOT occur, then the effect did not occur.

Fourth, we need to assume that the causal relationship does not go the other way.

Finally, we need to assume that there is no problem with the data.

Keep in mind as we review the answer choices, that the correct response is going to hit one of these five assumptions, and any choice that fails to tackle the problems inherent in a causal argument is not going to be the right answer.

Examining the Answer Choices:

Let’s start with A. It tells us that some of the students who weren’t part of the chess program learned to play chess elsewhere. This is not going to be the correct response because we want something that directly hits the link being playing chess and better intellectual achievements afterwards. I feel pretty comfortable eliminating this one right away.

Answer choice B says that children who started the program but then dropped out had lower grades before the program than the kids who finished the whole program.

This answer choice is really appealing, because it looks like it is going to hit our third assumption, that if the cause is not there, then the effect did not occur. But I’m a little confused about that phrase, “pre-program levels of achievement” I think I want post program levels of achievement, because that’s what we’re talking about.  Auugghh!  Confusion!  This answer makes my head hurt, so I’m going to keep it.

Answer choice C says: a lot of the kids who finished the program tried to join a chess team afterward that required a high GPA.

This one is easy to eliminate because we don’t care about their later chess memberships. We care about the relationship between chess skills and an improvement in achievement.

Answer choice D): Some kids who weren’t part of the chess program went to extra study sessions instead, and they performed better the next year.

This one looks good. It demonstrates that some kids who did not play chess nevertheless saw academic improvement by doing some other activity.  In other words, it wasn’t necessarily the chess.  But I’m not super happy with this.

And finally, answer choice E) says that some kids who didn’t finish the program were actually better chess players than some of the kids who did finish the program.

I don’t care how talented they are as chess players. I care about whether completing the program contributed to the skills they need to do better in school.

So we’ve eliminated three answers that aren’t great and we are left with two answers that seem to address the link between the skills learned in the chess class, and an increase in achievement after the class.

Let’s look at B) again.  Emotionally it is appealing because it has the words I am looking for, completion (or non-completion of the class) and levels of achievement. I want to like this one, but as I look closer, I see that answer choice doesn’t give us ANY information about the levels of achievement that occurred AFTER the class.  And since that is what the argument is trying to prove, this answer choice doesn’t hit the link that the argument is making.

I crossed everything off, so the one that’s left must be the right answer, right?

It must be answer choice D.  Right?


Nope.  Since we are trying to change the way you think, I’m going to ask you to work a little harder.  Let’s try to explain EXACTLY why answer choice D) is the right answer.

Answer choice D demonstrates that the chess class is not the only way that a student could gain the skills that would lead to increased academic achievement.

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So now we compare that to our conclusion, just to make sure we did it right and we find out….  Oh poop.  The conclusion is NOT saying that the chess class is the ONLY WAY a student can get those skills.

We are wrong. Now what?

Starting over:

Because the conclusion is so mild–Thus, it is likely that the reasoning power and spatial intuition exercised in chess-playing also contribute to achievement in many other areas of intellectual activity–we need to find an answer choice that shows that it isn’t likely that these skills contributed to the achievement. In other words we need to find SOME OTHER CAUSE.

As we go through the answer choices, the only choice that talks about how the kids who went through the program might have some other motivator for increasing their academic achievement is C.

Answer choice C tells us that it isn’t actually likely that it was the skills they learned, but in fact was their desire to get into the after school chess club that motivated them to increase their grades.

In sum:

I hate this question a lot.  This question is a time suck. If you were taking the test and found yourself eliminating all the answer choices over and over, I’d say you should just cut your losses and guess. (Moving on!)

But if you are doing this problem as part of a practice set, don’t give up.  Remember that you have to find reasons for why something is wrong as well as be able to explain why something is right.

In the end, the key here was finding the answer choice that showed that the conclusion was not necessarily true—a phrase you’ll hear me say, over and over!

When in doubt read the conclusion again.
That’s it for this question.  Stick around for more challenge questions in the future!

See ya!


  • Leigh

    Leigh has taught test prep for over 20 years in such far-flung corners as Madrid, Tokyo and San Diego. She considered going to law school but decided to get an MFA instead. Leigh has an official score of 174 and several unofficial 180—the result of years of tweaking techniques and approaches for her students’ benefit. She looks forward to passing on her wisdom to you.

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