You are right. We cannot assume that. Here, medical conditions lead to both a lack of X and a lack of Y. A lack of X may not have any causal relationship with a lack of Y. However, both (a lack of X and a lack of Y)are correlated - correlation just means happening together, not causal relationship.
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It is widely assumed that people need to engage in intellectual activities such as solving crossword puzzles or mathematics problems in order to maintain mental sharpness as they age. In fact, however, simply talking to other people—that is, participating in social interaction, which engages many mental and perceptual skills—suffices. Evidence to this effect comes from a study showing that the more social contact people report, the better their mental skills.

Which of the following, if true, most seriously weakens the force of the evidence cited?


(A) As people grow older, they are often advised to keep exercising their physical and mental capacities in order to maintain or improve them.

(B) Many medical conditions and treatments that adversely affect a person's mental sharpness also tend to increase that person's social isolation.

(C) Many people are proficient both in social interactions and in solving mathematical problems.

(D) The study did not itself collect data but analyzed data bearing on the issue from prior studies.

(E) The tasks evaluating mental sharpness for which data were compiled by the study were more akin to mathematics problems than to conversation.

It’s a causality casue and there are 3 ways to weaken a causality (find in manhattan books).

Cause : more Social Interaction

Effect: Better mental skilles

More SI --> Better MS

Ways to weaken a causality:

1) Alternate cause or factor

2) effect take place but cause was missing ….. like we need find a reason that mental skills increase without the increase in social interaction.

3) Effect happen only after the cause took place.

And many other ways

Our focus should be on the effect and casue.

The choices that you can easily eliminate are: A,C and D

You are left with "B" and "E"

In E you can see that the effect was discussed I.e. the mental sharpness. Mental data was changed or something was done with the mental data.

But mental sharpness is the result I.e it is caused by some other factor and that factor is social interaction. So, if we will modify or change something related to the social interaction than that would weaken the conclusion.

That’s is why between "B" and "E" , "B" is the best choice.

Plz correct me I am wrong.

Focus on what your premises give you and what your conclusion is:

Argument:

Premise: a study shows that the more social contact people report, the better their mental skills.
(that social contact and mental skills are related. How? We don't know)
Conclusion: Social contact is enough for mental sharpness
The author believes that social contact leads to mental sharpness.

We need to weaken it.

(B) Many medical conditions and treatments that adversely affect a person's mental sharpness also tend to increase that person's social isolation.

Option (B) says that there is a third factor - 'medical conditions and treatments' which cause both social isolation and mental decay. Option (B) tells you that there is a different "cause" for both conditions and that is how they are related. So if people who are socially isolated also have weak mental strength, it could be because of medical reasons. The social isolation may not be the reason for lack of mental strength. So others who have enough social contact and strong mental skills, it could be because they do not have these medical conditions.
This weakens our conclusion that social contact causes mental sharpness.
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Yes you are right

This is a classic Causality Question.
the conclusion says that due to social interaction, mental health improves. But we need to weaken it

Now the option says that actually mental health affects social interaction (but in a negative way)

This is reversing our casual relation, and hence a weakener

This is just showing a negative correlation, and not a causal relation

(A) As people grow older, they are often advised to keep exercising their physical and mental capacities in order to maintain or improve them.
no relation with our analysis
they can do exercise using math skills or social interaction

(B) Many medical conditions and treatments that adversely affect a person's mental sharpness also tend to increase that person's social isolation.
>> mental sharpness is inversely proportional to social isolation.
means it weakens our premise- 2 ( with additional premise 3)
matches our analysis

(C) Many people are proficient both in social interactions and in solving mathematical problems.
>>but it doesn't give us clarity that mathematical problems are not needed and only social interactions are enough

(D) The study did not itself collect data but analyzed data bearing on the issue from prior studies.
>>it doesn't matter how u get to study report

(E) The tasks evaluating mental sharpness for which data were compiled by the study were more akin to mathematics problems than to conversation
this option is very tempting and we may misinterpret it with our finding 1.
We can closely read this option as we have one back up option B for the answer.
So lets read carefully to make the distinction between B and E

>> so the study was based on mathematical problems and still evidence suggests that the person should do social interaction. This option, if anything, strengthens conclusion.

Hence final answer B

Hi GMATNinja VeritasKarishma - I keep reading that this question has a causality element. I don't agree with it.

Instead,

The premise has a correlation element specifically : Increased A --> Increased B [This is correlation element , not causality]

Conclusion : A is all you need to maintain B

Where is the causality in the conclusion specifically ? The author when he says -- A is all you need to maintain B is NEVER saying or implying in his conclusion : A CAUSES --> B

Now in order to weaken this, the strategy may be the same which is used in typical causal questions [Which is why people are throwing the Causality element around ? because the strategy to weaken this question and other causal questions, may be the same]

You need to just prove perhaps Z is what is causing Increased A and Increased B BOTH (or vice versa -- Z is what is behind Decreased A and Decreased B BOTH )

Thoughts on my analysis ?

An argument will very rarely say "A is the cause of B." You will need to infer what the argument is giving. Here it is giving "talking to others" (A) maintains "mental sharpness" (B). So A leads to B.

It says people assume that intellectual activities are needed to maintain mental sharpness. But actually, just talking to others is sufficient (to maintain mental sharpness).
So talking to others leads to mental sharpness as per the argument. The argument is giving causality.

Sometimes the argument says "a study found that people who have high A have high B too" and it goes on to conclude that A leads to B. This is where we question that causality is not given but concluded.
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Hi,

Can you please explain how we can infer from option B that lack of B causes lack of A. What I inferred is the following:
A (Social Interaction) leads to B (Better mental skills). So it can be inferred from the correlation between A and B that Less A leads to Less B. According to choice B: another factor C leads to less A as well as less B. Therefore, we can't say that there is a correlation between A and B.

Can please someone help me on this. GMATNinja EMPOWERgmatVerbal

(x = social contact & y = mental sharpness)
Here We have to weaken that
MORE X --> MORE Y

Doubt 1) does this mean that less x --> less y ? OR without X --> y would not be reduced.
basically can we flip it to weakening less X ---> less Y ?

in choice b) :
Z --> less y --> less x ( reverses the causal relation)

z is an alternate cause that leads to the reverse of the causal relation but in "less" terms not in "more"

Doubt 2) Is it right to show an alternate cause for less x & y when the argument is talking about more x & y

Z --> LESS y --> less x ; Then can Z --> MORE y --> MORE X

eg:
WKN : LESS EXERCISE --> MORE FAT LOSS

when making an argument map can we say with certainty that :
WKN : MORE EXERCISE LEADS TO MORE FAT LOSS. (logical flip)

{Basically can less and more be flipped keeping X & Y on the same ends of the Cause --> Effect Relationship}
{OR CAN LESS & MORE DONT MATTER IF X --> Y IS REVERSED TO Y--> X }

This is a great question. I personally think what makes it difficult is not only the question designer's use of double negatives in the correct option (B), but also the use of a very general term "mental sharpness." What does the term "mental sharpness" refer to? Does it refer to a person's ability to solve math problems quickly? Or does it refer to the capability to socialize and have conversations with people? Even though these two capabilities seem really disparate to me, and even though I think neither of them can help boost another, the question designer surprisingly categorizes them both as the abilities showing "mental sharpness."

In other words, even though we might agree that a person who is good at math and a person who loves chatting could likely be "smart" in different ways, they both could be considered "mentally sharp," according to the stimulus.

Hi IanStewart and avigutman

I have three questions:

1. In some previous posts in this thread, several club members have discussed whether there is a correlation or causal-effect relation in the final sentence "Evidence to this effect comes from a study showing that the more social contact people report, the better their mental skills." However, since there is no unanimous opinion, I would like to discuss this issue again. (The official explanation says that the study shows a correlation, while some members and experts agree that there should be cause and effect.)

I personally think that the use of the idiom "the more A, the more B" itself shows a cause-effect relation, as the idiom basically says that B is the effect of A. But, not many members have used this idiom to confirm the causality--more people say that because the author links the evidence to his or her conclusion, there is a cause-effect relation. What do you think? Could I rely on the idiom to confirm the causality?

2. I can understand that the option (B) introduces a third factor that affects a person's social interaction and mental sharpness and thus breaks the link between social interaction and mental sharpness. But since the information in the option (B) is kind of presented in the opposite direction to the study's, I hope to learn how to connect the information back to the argument.

If the option (B) is true, does it mean that if the study's researchers have failed to take the subjects' medical conditions into account and have not designed the experiment sample properly--which could likely be true even though we cannot know for sure--the study results might have been "not pure" and thus cannot be used to show whether there is a relation between social interaction and mental sharpness?

(If the researchers hope to avoid the influence of medical conditions, they should select subjects whose medical conditions are similar, and test whether more conversation leads to higher mental sharpness.)

In other words, what the option (B) does is casting a doubt on the connection between the evidence and the conclusion by indirectly pointing out that there might be an error in the experiment, right?

3. The option (E) was tempting to me. Since I kept thinking that the skills required in math problems and conversation should be different, I made an inference that because the researchers rely on using math problems to measure people's mental sharpness, the skills required for solving math problems should be more like the "standard skills" required for being mentally sharp.

I noticed that some experts have pointed out that the option (E) can actually strengthen the argument. I was a bit surprised, but perhaps it makes sense. Even if I go extremely to say that the skills for solving math problems are "standard skills," the study result shows that somehow (magically) the more people talk to others, the better math skills they have. This result does not weaken the conclusion.

I drew an analogy to help myself see the option (E) better and hope you could check my analogy:

It is widely assumed that people need to do cardio to maintain physical strength, but actually weight lifting is enough. Evidence to this effect comes from a study showing that the more frequently people lift weight, the stronger their physical strength.

The option (E) would be like: To measure subjects' physical strength, the study gave subjects tasks that are more like cardio than weight-lifting.

Even though we might wonder why the researchers prefer using cardio as the gauge--does it mean anything? such as "cardio is better?"--we cannot thus attack the evidence. Since the more frequently people life weight, the better physical strength they have, the conclusion that lifting weighting is enough for maintaining the physical strength is not hurt.

Thanks you so much!

I actually disagree with the above, GraceSCKao. The stimulus merely implies that mental skills are a measure of mental sharpness. All that other stuff (intellectual activities such as solving crossword puzzles or mathematics problems; simply talking to other people—that is, participating in social interaction, which engages many mental and perceptual skills) -- those are just things that are widely assumed or are the author's claim to suffice in order to maintain mental sharpness as they age.


I wouldn't infer causality from the idiom the more A, the more B. It's merely a correlation. Perhaps I can use the last sentence of the second paragraph in this official RC passage to support my claim. Would you agree that the higher O18:O16 ratio didn't cause an increase in land ice? The second paragraph makes that clear in my opinion - it describes/explains why the two things are correlated.


The short answer is Yes. Reacting to the parts of your question which I boldfaced in your quote. the third factor doesn't "break the link" - it merely suggests an alternative explanation for that link. The author used the link (a.k.a. the correlation) to infer causation, but causation is only one possible explanation for a correlation. Option (B) suggests that if the experiment wasn't "pure" then there's an alternative explanation for the observed correlation (thereby increasing our doubt in the author's implied explanation of the correlation). "there is a relation between social interaction and mental sharpness" we know in fact that such a relation does exist; what we're debating is whether one causes the other.


Your analogy seems good to me. My reaction to option (E) was the following:
The study showed a correlation between social contact and mental skills. The author jumped to a conclusion about causality (the former causes the latter). Does the author's conclusion depend on the specific tasks used to evaluate mental sharpness? No, I don't see why it would (unless the tasks were completely absurd, e.g. evaluating my mental sharpness by counting how many pull-ups I can do in a row.)

In general, GraceSCKao, since I wound't want your takeaways to be limited to this particular problem:
This question is testing one of the most commonly tested concepts on the GMAT (and in job interviews and in life in general). Is it appropriate to draw conclusions about causation based on evidence of correlation (it's not). That's precisely what the author did in this argument (and most people do on a daily basis). Let's review the conclusion:
simply talking to other people—that is, participating in social interaction, which engages many mental and perceptual skills [suffices] to maintain mental sharpness as [people] age.
This is based on a study showing
the more social contact people report, the better their mental skills.

My pre-thinking for this particular correlation causation issue was as follows (in case it's helpful):
Did you notice that I boldfaced the word "report"? I did so because that word causes me to lose 90% of my confidence in the results of the study. I can certainly see why people who have better mental skills would report more social contact. Maybe they're more likely to remember the social contact that they had; maybe they are better at identifying what it is that the researcher is hoping to hear; maybe they are more inclined to exaggerate their reports of social contact. Any one of those would provide an alternative explanation for the correlation: it's not that social contact improves mental skills - it's the other way around!

The correct answer in this case didn't flip the direction of the causation; it provided a third factor causing both elements. That's precisely the kind of answer we should be looking for, in the absence of a "direction flip" option. Very similar to what we saw here.
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It is widely assumed that people need to engage in intellectual activities such as solving crossword puzzles or mathematics problems in order to maintain mental sharpness as they age. In fact, however, simply talking to other people—that is, participating in social interaction, which engages many mental and perceptual skills—suffices. Evidence to this effect comes from a study showing that the more social contact people report, the better their mental skills.

Which of the following, if true, most seriously weakens the force of the evidence cited?

(A) As people grow older, they are often advised to keep exercising their physical and mental capacities in order to maintain or improve them.
(B) Many medical conditions and treatments that adversely affect a person's mental sharpness also tend to increase that person's social isolation.
(C) Many people are proficient both in social interactions and in solving mathematical problems.
(D) The study did not itself collect data but analyzed data bearing on the issue from prior studies.
(E) The tasks evaluating mental sharpness for which data were compiled by the study were more akin to mathematics problems than to conversation.

I am not able to understand how option (B) is the correct option here.
The argument talks about older people or people who age mentioning that as they age they ONLY need to have social interations to maintain their mental and perceptual skills. Option (B) talks about those people who undergo medical conditions and treatments, which is irrrelevant to the document. I can understand that option (B) is the only option which attacks the argument/underlying assumption, but it talks about a group of people undergoing medical treatment, which has not been discussed.

Hence, I chose option (E) because it effects the results of the experiment conducted by considering that its results were based more on mathematical interpretations that on social interactions/ conversations.

Kindly please help me rectify this discrepancy
KarishmaB Sajjad1994 egmat EMPOWERgmatVerbal carouselambra nightblade354 GMATNinja

nayas96 We're looking to "weaken the force of the evidence"; your reason for eliminating option (B) is good under the assumption that there's zero overlap between the people with medical conditions and treatments and the people who participated in the study. If the overlap is greater than zero, then option (B) does weaken the force of the argument. We have no reason to suspect zero overlap, so we should choose option (B).
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Thank you avigutman so much for your detailed explanations!

I was aware that we need to pay attention to the use of adverbs and quantity modifiers such as "some" or "none," but I did not notice that even the choice of verbs could make a huge difference in meaning. You are absolutely right that with the verb "report," we have a lot of space to suspect the accuracy of the study results. I think if it were written in a more neutral-and-scientific language such as "the researchers observed that the more social contact people had," the room for such suspect would narrow. Certainly we could still doubt whether the researchers have made any mistake in their observation, but in tougher CR questions, I think such an option that directly attack those who do the experiments do not show up frequently.



Sorry that I raised another question after your detailed explanation. I just hope to check this CR question you mentioned. I recently finished reviewing this question (thank you for your explanations in that thread.). I thought that question centers around correlation, not causation, does not it? The author thinks that it is surprising that a group of people have two characteristics at the same time, and thus he or she asks us to find an explanation. Basically what the option (C) does is confirming the correlation. So, this question does not have the "direction flip," right?

An experiment was done in which human subjects recognize a pattern within a matrix of abstract designs and then select another design that completes that pattern. The results of the experiment were surprising. The lowest expenditure of energy in neurons in the brain was found in those subjects who performed most successfully in the experiments.

(C) People who are better at abstract pattern recognition have more energy-efficient neural connections.

Thank you so much for your insights!

Both questions present a "surprising" correlation (social contact ~ mental skills and low energy expenditure in neurons ~ success in abstract design pattern recognition).

The big difference between the two questions, GraceSCKao, is that the author jumps to a conclusion about causation (social contact maintains mental sharpness) in only one of them. The problem with what the author did is that the causation is only one of many possible explanations for the surprising correlation. Our job is to "weaken the force of the evidence", and the way to do that is to suggest one of the other possible explanations for the surprising correlation. Whereas in the other question, the author doesn't jump to any conclusions explaining the surprising correlation. Rather, our job there is to pick out the answer choice that would explain the surprising correlation.

So, in both questions we must choose an answer choice that proposes a reasonable explanation for the surprising correlation. And, in both questions the correct answer provides an explanation that doesn't involve any causation between the correlated items. In one case it provides a third factor that causes the other two (medical conditions and treatments), and in the other case it provides a third factor that happens to be correlated with each of the two factors (energy-efficient neural connections).


It doesn't confirm the correlation (and we're not looking to confirm it, we're looking to explain it). Neither of the questions' correct answer does a "direction flip". In the abstract pattern question there is no proposed direction, so there's nothing to flip.
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Understand the Passage

It is widely assumed that people need to engage in intellectual activities such as solving crossword puzzles or mathematics problems in order to maintain mental sharpness as they age.This sentence starts with “It is widely assumed”. When I read this, I know that the author will very likely contradict this part.

Think about it.

Generally, when you talk about the assumptions others make, you are likely going to contradict them.

The assumption is that people NEED to engage in intellectual activities to maintain mental sharpness as they age. (Please note that the pink-colored part just provides info about the intellectual activities. So, while trying to understand the complete statement, you may ignore it.)

The keyword here is “Need”. When you say “X is needed for Y”, you mean that Y CANNOT happen without X. In other words, X is necessary for Y.

So, the assumption is that one cannot maintain mental sharpness as one ages without engaging in intellectual activities.

In fact, however, simply talking to other people – that is, participating in social interaction, which engages many mental and perceptual skills-suffices.

This statement starts with “however”, which indicates a change in direction. We can expect something contrary to the point made in the first statement.

The statement says that simply talking to other people suffices. (Again while understanding the complete statement, I ignore the pink part providing additional info about “simply talking to other people”.)

Suffices for what?

We need to understand this from the given context. In the first statement, the author talked about a general assumption that X is needed for Y. This statement starts with “however” and says that Z suffices. It means that Z suffices for Y i.e. simply talking to other people is sufficient to maintain mental sharpness.

Thus, this statement completely contradicts the previous statement. This statement means that “engaging in intellectual activities” is not necessary for maintaining mental sharpness.

Well, this contradiction is what I expected when I read “widely assumed”. So, everything seems to be fitting in till now.

Evidence to this effect comes from a study showing that the more social contact people report, the better their mental skills.This statement provides evidence for the preceding statement. The evidence is the result of a study. The study shows that more social contact people report, the better their mental skills.

We can see that the Second Statement is the Conclusion supported by the Third Statement.

Predict an Answer

Conclusion: Simply taking to other people is sufficient to maintain mental sharpness as one ages.

How is it supported?

A study showed that more the social interaction people report, the better their mental skills.

One of the most important parts in solving argument based questions is understanding HOW the premises support the conclusion.

In this case, the study showed two things happening together: more social contact and better mental skills. The argument concluded that social contact is sufficient for mental skills.

The argument thus assumed that in the study, more social contact led to better mental skills.

Why is this the assumption?

Because if we do not assume that social contact was the cause of better mental skills in the study, then how can we make the conclusion on the basis of the study?

If you pay attention to the assumption, it is a causal statement. X caused Y. or X led to Y.

In a way, the reasoning in the given argument is a standard causal reasoning in a lot of GMAT and real life arguments. We see two things happening together, and we say one is the cause of the other. For example: a lady is beautiful and lands a plum job. Some people may conclude that her beauty led to her job. But it may be her intelligence that led to the job. Are you sure that she is not more intelligent than others?

Such a causal conclusion or assumption can be broken down in a number of ways. For example: If the conclusion/assumption is that X led to Y (on the basis of the observation X and Y are happening together), then it can be broken down if we say:

1. Y led to X
2. Z led to X and Y
3. Y happened before X.

In each of the above ways, we allow our observation to stand as is and still break down the causality “X led to Y”.

The given causality can be broken in each of these ways:

1. People with better mental skills are more likely to be confident and thus have more social contact than others. (Mental skills are leading to more social contact)
2. People from affluent background are more socially active than others and have better resources available for building their mental skills. (Affluence is leading to both social contact and mental skills)
3. I’m not able to think how I can say that the mental skills existed before the social skills. So, if you have any idea on how I can construct this situation without offending common sense, please share your thoughts in the comments

Frankly, the argument is not just assuming this causality but stretching it even further by saying that simply taking SUFFICES. How can we say that it was sufficient? Probably, there were other factors at play that we are not considering.

So, by challenging the causality or by challenging this “sufficiency” part, we can weaken the argument.

Option Analysis

(A) Incorrect. This option says that people are advised to exercise their mental skills to maintain them. But it doesn’t talk about how? Are they advised to maintain their mental skills by speaking to other people or by engaging in intellectual activities? The option doesn’t talk about it. Thus, this option neither strengthens nor weakens the conclusion.

Now, the next logical question is “what if the option talked about a specific way to build mental skills?”. What if the option were:

“As people grow older, they are often advised to keep exercising their mental capacities by engaging in intellectual activities in order to maintain or improve the mental capacities.”

Would this weaken the argument?

The answer is No. The advice could be wrong. Besides, the argument already states that intellectual activities are widely believed to be necessary for maintaining mental sharpness. So, it isn’t surprising to expect that people would be advising such activities. Thus, the argument is not weakened even by this modifies option.

(B) Correct. This option talks about a factor that has a negative impact on both the mental sharpness and the social contact. Thus, a person with this factor will have less social contact and less mental sharpness than a person who doesn’t have this factor.

Right?

Thus, this option indicates that it is not that more social skills are leading to more mental sharpness or less social skills are leading to less mental sharpness; rather, it is the factor that is affecting both the social skills and the mental sharpness.

This option weakens the argument by bringing in a Z-factor (2nd way of breaking down a causal argument as mentioned above).

(C) Incorrect. This option says that many people are skilled both in social interactions and in solving mathematical problems.

Good to know? But is one the cause of the other?

The option doesn’t say anything about that. It just says both exist simultaneously in some people.

Besides, we are not concerned about the social skills. We are concerned about social contact i.e. the number of hours you spend talking to other people, not how skilled you are while talking to them. Right?

(D) Incorrect. This option says that the study did not rely on primary data but on secondary data.

Some people take it to be a weakener. They think that data from other sources may not be reliable. But the point is that it may also be equally or even more reliable than primary data. For example: if I use data from WHO in my study, is my study in any way less reliable than a study in which the researchers themselves are collecting data?

No. Just because it is secondary data doesn’t mean that it is not reliable. That is an incorrect logic.

(E) Incorrect. This option is a very attractive choice for a lot of people. To understand it, let’s look at its opposite:

The tasks evaluating mental sharpness for which data were compiled by the study were more akin to conversation than to mathematical problems.

(I’ve swapped the positions of “conversation” and “mathematical problems”. By doing so, I’ve negated the original option)

Now, this statement means that we evaluated the mental sharpness in the study by giving “conversation” tasks rather than mathematical problems. Now, if we did so, we’d naturally expect people with more social contact to perform better on such tasks and thus show more mental sharpness. Right?

Thus, this situation will cast a doubt on the conclusion by indicating that it is not that social skills are leading to mental sharpness but that we are measuring mental sharpness in a biased way that we are seeing the given trend in the study.

So, we see that actually the negation of this option will weaken the conclusion. Thus, the actual option should strengthen the conclusion since it is negating a weakener. Right?
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Dear Experts,

I have really read all the comments and explanation in this thread.
But I am still confused (B).
I understand why (E) and others are wrong. but I am not convinced why (B) is correct.

The passage doesn't mention anything about medical conditions. I understand that weaken and strengthen can be out of scope but (B) doesn't tell anything about relation between Mental Sharpness and Social Contact.

Even third factor, such as medical conditions, does affect or cause both Mental Sharpness and Social Contact but it is also possible that Social Contact does cause/help Mental Sharpness/skills.

Medical >> Social Contact >> Mental
Medical >> Mental

If a correlation exists between X and Y things, there are exactly three possible reasons for the correlation:
1/ Changes in X cause changes in Y.
2/ Changes in Y cause changes in X.
3/ Some third thing Z causes changes in both X and Y.

(If the correlation is positive, the "changes" here will go in the same direction—i.e., an increase in X will correspond to an increase in Y, and likewise for decreases. If the correlation is negative, the changes will go in opposite directions.)

If an argument concludes that one of these is true, that argument is weakened by pointing out that one of the other two is true.
In this case, medical conditions are the third factor 'Z'.




That's just what the original argument says. There's no reason to restate it.

If you're trying to point out that the original conclusion isn't disproved, that's fine—nobody ever said you should disprove anything! Weakening an argument is not the same as disproving it.
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Hi RonTargetTestPrep - does option (B) really state what you have in (3) above ?

I see option (B) stating,
(Z) is causing correlation b/w (NOT Y and Not X)
and/or vice-versa
(Z) is causing correlation b/w (Not X and Not Y)

How do you then take : (Z) is causing correlation b/w (NOT Y and Not X) or (Not X and Not Y) and then flip the double negatives to say : (3) is taking place ?

I was looking for something that said Z is causing (both X and Y)