#22 - In an experiment, two-year-old boys and their fathers

[Dave Killoran]

Complete Question Explanation

Must Be True. The correct answer choice is (B)

The “rolling pin” problem is a famous question that lured many people to incorrectly select answer choice (D), a Shell Game answer. Answer choice (D) looks perfect at first glance, but the author never indicated that the children could identify only the utensils that they used. Rolling pins, yes; utensils, no. The correct answer choice is (B), which many test takers quickly pass over. Let’s examine each answer:

Answer choice (A): From the text, it seems possible that the children did understand the function of a rolling pin; certainly, they were able to identify the rolling pin they used.

Answer choice (B): This is the correct answer choice. The answer must be true because we know that despite being asked to identify all the rolling pins, each child selected only the rolling pin he had used. No two children picked the same rolling pin and therefore no two children understood the name “rolling pin” to apply to the same object. Also note how in this Most Strongly Supported question the answer is fully proven.

Answer choice (C): Apparently not, otherwise logic would say the children would pick other rolling pins in addition to the one they used.

Answer choice (D): Do not be concerned if you fell into this trap, but consider it a lesson for the future. The test makers smoothly slip “utensils” into the answer choice, and most students make the mistake of equating utensils with rolling pins. Yes, a rolling pin is a utensil, but there are other utensils as well, and the stimulus does not give us information about whether the children could identify those utensils. This is the essence of the Shell Game: you expect one thing and the test makers slip something quite similar but essentially different into its place.

Answer choice (E): This is an Opposite Answer. As indicated by the final sentence of the stimulus, the children were able to distinguish the rolling pin they used from the other rolling pins. This circumstance is exactly opposite of that stated in answer choice (E), which declares, “The children were not able to distinguish...” In this case, if you miss the “not,” this answer choice is very attractive.

[PositiveThinker]

I see how B is right but i just don't see how D is wrong.

"each child was able to identify correctly only the utensils the the had used".. Ive read this statement over and over, in 3 different languages that i speak and it still is not clicking how it is not strongly supported by the stimulus.


Fairly old test, so if its part of the curriculum after all these years, its clearly a legitimate question with 4 wrong answer choices, i just need to know why D is wrong.

thanks a lot!

[Emily Haney-Caron]

Hi PositiveThinker,

Thanks for the question, and for taking the time to explain your reasoning on this one! The trick here is that we don't know the child can only identify the utensil he used; it could be instead that the child can identify only utensils that look like the utensil he used. So, if there were two identical or very similar rolling pins in the bunch, the children who used those rolling pins may very well be able to pick out both of them. The identification ability may or may not have to do with it being the rolling pin that child used; instead, it seems to have to do with it being the kind of rolling pin the child learned the name of. It's a minute distinction, but an incredibly important one for ruling out D!

[andriana.caban]

Hi,

I eliminated (D) because I thought "only" was too definitive of a word which is unsupported by the stimulus since the author states there are "rolling pins and other utensils". Is the reasoning behind my elimination of (D) accurate and on par with your earlier analysis of this problem? Thanks!

[Charlie Melman]

Hi Andriana,

You're right to want to match the scope of what's described in the answer choice to the scope of what's described in the stimulus. And you identified a phrase from the stimulus that's critically important But I think you're just a little off the mark with respect to why answer choice (D) is wrong. The issue with answer choice (D) is that the stimulus tells us only about the children's ability to identify rolling pins. We have no idea what else the children were asked to identify. Answer choice (D), though, talks about identifying "utensils," and we know from the stimulus that rolling pins are just one subset of "utensils" (see: "rolling pins and other utensils"). So answer choice (D)'s problem is that it's over-inclusive. It could be true, in theory, but it's not most strongly supported by the information in the stimulus.

I hope this helps!

[andriana.caban]

It does, thank you!

[Kennedv_]

Hi,

I eliminated B right away as I was going down the list because of the "no two children" part. For example, how do we know there weren't 20 father-son pairs and there were only 5 types of rolling pins causing there to be a couple instances where multiple pairs used the same rolling pin (and then as for the result, there would have been two children that picked the same rolling pin). I figured that in order to conclude that "no two children understood..." we would've had to have been told some information about the group number.

I think I have completely misread/other thought/botched this entire question but I guess I'm trying to figure out how we can say "no two children" when we don't really have numbers on anything.

Thanks for the help in advance!

[Dave Killoran]

Hi,

I eliminated B right away as I was going down the list because of the "no two children" part. For example, how do we know there weren't 20 father-son pairs and there were only 5 types of rolling pins causing there to be a couple instances where multiple pairs used the same rolling pin (and then as for the result, there would have been two children that picked the same rolling pin). I figured that in order to conclude that "no two children understood..." we would've had to have been told some information about the group number.

I think I have completely misread/other thought/botched this entire question but I guess I'm trying to figure out how we can say "no two children" when we don't really have numbers on anything.

Thanks for the help in advance!

Hi Kennedv,

Well, this is how they get you. They created a scenario full of details and where your expectations didn't match reality, and so when you saw (B) you were prone to eliminate it out of hand. That said, this problem doesn't contain an error, so either you misread it as you said, or misunderstood what they said. That happens to everybody, so let's see what we can learn here from it!

First, if you haven't already, go back up to the top and read my explanation of this problem. It's a question I cover in the Logical Reasoning Bible, so it's a problem I not only love, but an explanation that has been vetted by thousands of readers.

Second, the details in this problem are many and they are varied, and if you break down what you said you will begin to see the issues. For example, you said, "...how do we know there weren't 20 father-son pairs and there were only 5 types of rolling pins causing there to be a couple instances where multiple pairs used the same rolling pin (and then as for the result, there would have been two children that picked the same rolling pin)." Well, we know that from the second sentence, which opens with: "Each father-son pair used a rolling pin that was distinctively different from those used by the other father-son pairs..." So, you can't have the overlap scenario you describe. And, as you probably suspect now, it's that kind of individual separation that later substantiates the "No two children" claim in (B).

So, what I'd suggest is going through this problem multiple times until everything has clicked. It's a killer problem, and so indicative of how they test you on tricky problems. You may have missed this one this time, but you can learn a ton from it and avoid similar errors next time. Good luck!

[ShaharaHossain]

I still need help understanding answer choice b. The passage repeated used “each” and also used “father son pair” and “father son pairs”. Where in the passage can we conclude that there are only 2 children?

[Dave Killoran]

Hi Shahara,

We can't, actually, and so I suspect your issue with B might be coming from thinking there are only two children. There's no claim in either the problem or the explanations above that there are only two children (there could easily be more). Answer B is using "no two children" as a way to say that no child had the same understanding as any other child, that is, each child gave a unique answer (by picking only their rolling pin) when asked.

Consider this example: "No two people at this party have on the same shirt." does that mean there are only two people at the party? No, it just means that you can look at everyone there are not find two people with the same shirt on, meaning each person has on a different shirt.

Please let me know if that helps. Thanks!