Q22 - In humans, ingested protein

[irini101]

I chose the correct answer, although I know choice A is flawed and exact opposite of choice D but I cannot pinpoint why the relation has to be the direction of choice D instead of choice A?

I diagram the stimulus as follows:
premise: sugar--> rid amino leaving trytophan-->serotonin
conclusion: sugar--> mood elevation

Here comes the confusing part: I could prephrase the correct answer should connect serotonin with mood elevation, but I am confused about the direction of the connection:
serotonin--> mood elevation
mood elevation-->serotonin

I choose choice D out of gut feelings but I need to clear up the direction. Is it because directions always go from premise to conclusion thus it should start from serotonin towards mood elevation?

If it is, can I apply it to other questions with situations demanding connection a keyword in premise and another keyword in conclusion by: kw in premise--> kw in conclusion?

Could you please explain? Thanks a lot in advance! ：目

[chike_eze]

I chose (A) initially -- got turned around on this one.

Basically, I believe the flow is:

Sugar -> Increasing Serotonin
therefore,
Sugar -> mood elevation and relaxed and anxiety-free

Gap: Increasing Serotonin -> mood elevation and relaxed and anxiety free

If the above flow is correct, then
(A) is wrong because it goes in the wrong direction; i.e.,
mood elevation and anxiety-free -> Increasing Serotonin

But I'm still unclear about (D).
Increasing Serotonin -> relaxation and anxiety-free

Because (B) seems incomplete. But wait... If this is a necessary assumption question, we don't need to fill the whole gap!

Assuming my diagramming is accurate, is that what makes (D) correct? i.e., that Necessary assumptions need not fill the entire gap in the argument.

Throw darts here please!

[chike_eze]

After responding to the two posts above, take a stab at this one too.

What is the difference (or not) between the following statements:

1) Money can play a major role in Sheila's happiness, helping her feel more relaxed and anxiety-free

2) Money can play a major role in Sheila's happiness, which can help her feel more relaxed and anxiety-free

Diagram both if you think it's necessary. I want to make sure I'm not reading too much into the supposed difference between the two statements. And even if such a difference exists, does it matter in the context of the LSAT??

[demetri.blaisdell]

Both of you are on the right track on this problem. You've both correctly identified the gap in the argument core below:

sugars lead to increase in serotonin levels ---> sugars can help one feel relaxed and anxiety-free

The gap is that we need a connection between serotonin levels and mood. (D) gives us exactly that connection.

What's going on with (A)? If you accept the term shift from "mood elevation, helping one to feel relaxed and anxiety-free" to "elevation of mood and freedom from anxiety," the issue is which direction the logic flows. (A) tells us that in order to achieve the mood elevation, we must have an increase in serotonin. Is this necessary for the argument to work? No! Try the negation test. Even if mood elevation doesn't require the increase, it could still play a major role.

Back to your question, irini101: I try my best to convince my students that looking at vocabulary as proof that an answer choice is correct is dangerous and counterproductive. I can't give you a rule about where to look for key words. Instead, trust your intuition. If you're not totally sure, ask yourself the question stem again. Does the argument depend on this assumption? If you're still not sure, apply the negation test. I wish there was a trick to all of this, but there isn't.

Now for chike_eze's question. It's always tricky to evaluate logic when you don't have context, but I'll give it a shot.

The difference I see between (1) and (2) is really grammatical. In (1), the money is what helps Sheila to feel more relaxed and anxiety-free. In (2), depending on how you read it, it is Sheila's happiness that helps her feel more relaxed and anxiety-free.

I hope I've been able to help both of you understand this better. Let me know if you have any questions.

Demetri

[chike_eze]

Now for chike_eze's question. It's always tricky to evaluate logic when you don't have context, but I'll give it a shot.

The difference I see between (1) and (2) is really grammatical. In (1), the money is what helps Sheila to feel more relaxed and anxiety-free. In (2), depending on how you read it, it is Sheila's happiness that helps her feel more relaxed and anxiety-free.

Thanks for the explanation. In your experience, is it common for LSAT writers to use variations in (1) and (2) to confuse cause-and-effect or conditional reasoning relationships?

For example:

1) Money makes people Happy, which makes them Greedy
2) Money makes people Happy, making them Greedy

In my opinion,

The first would be
Money -> Happy -> Greedy

The second..
Money -> Happy
Money -> Greedy

@Demetri,

LSAT writers play lots of tricks with words... would this be one of them?
Or is this level of scrutiny unnecessary?

Thanks!

[demetri.blaisdell]

The LSAT has a lot of tricks, but I've never seen that particular one. Detail creep in wrong answer choices can hinge on one or two words, but it's more often something like more/most or majority/many. In general, I would recommend sticking to real questions for your review. It's good to have a strong understanding of the conditional logic but then you need to apply it to Binary Grouping games and Inference LR questions. Happy studying!

[Mab6q]

I have two quick questions if someone wants to chime in.

1. In regards to A, would the answer choice be necessary if the logic were reversed.

increasing level of serotonin --> elevation of mood and freedom.
I understand how this is sufficient to establish the conclusion, but is it necessary? Do we need to know that elevation of mood and freedom is required to increase the level of serotonin??? The argument does not say that sugars always play a role in mood elevation, just that they CAN.

2. Real quick, would we consider B a strengthener. It establishes a possible causal relationship between foods rich in sugars and anxiety and a lowering of mood.

Thanks guys.

[maryadkins]

If (A) were different and read:

increasing Serotonin --> elevates mood

then negating this for purposes of a necessary assumption question would be to say:

increasing Serotonin DOESN'T necessarily lead to mood elevation

Does the argument fall apart?

Nope. Just because it doesn't necessarily lead to a better mood doesn't mean it can't.

Lesson: To negate a conditional statement for purposes of a necessary assumption question, this is what you do. If the statement you're negating is X --> Y, you say, "X doesn't necessarily lead to Y" and see what happens.

And to your other question, I'd say (B) strengthens, yeah.

[Mab6q]

If (A) were different and read:

increasing Serotonin --> elevates mood

then negating this for purposes of a necessary assumption question would be to say:

increasing Serotonin DOESN'T necessarily lead to mood elevation

Does the argument fall apart?

Nope. Just because it doesn't necessarily lead to a better mood doesn't mean it can't.

Lesson: To negate a conditional statement for purposes of a necessary assumption question, this is what you do. If the statement you're negating is X --> Y, you say, "X doesn't necessarily lead to Y" and see what happens.

And to your other question, I'd say (B) strengthens, yeah.

Thanks Mary! You guys are absolutely the best in the business.

[Emmeline Ndongue]

If (A) were different and read:

increasing Serotonin --> elevates mood

then negating this for purposes of a necessary assumption question would be to say:

increasing Serotonin DOESN'T necessarily lead to mood elevation

Does the argument fall apart?

Nope. Just because it doesn't necessarily lead to a better mood doesn't mean it can't.

Lesson: To negate a conditional statement for purposes of a necessary assumption question, this is what you do. If the statement you're negating is X --> Y, you say, "X doesn't necessarily lead to Y" and see what happens.

And to your other question, I'd say (B) strengthens, yeah.

This particular PT seems to play a lot with conditional and causal relationship.
Just want to add that I think answer choice A suggests a conditional relationship rather than a causal relationship, since it uses the word "requires"
so if A is given in the opposite direction, we have incr. lv. of serotonin -> elevation of mood/freedom
then supposedly it's negation would be incr. lvl of serotonin "might not get".elevation of mood/freedom ?
It seems here, it still wouldn't destroy the argument.

[charlottew997]

Can a SA answer be the correct choice for a NA question too?

When I’m reading Loophole, the book suggests SA—>Conclusion True—>NA, so I thought NA should be sth. justified by a valid conclusion, not something that fills the gap between premise and justify/validate the conclusion (this is exactly what SA should do).

This formula is also proven by the negation test widely used to solve NA questions. Negation test states that ~NA—>~Conclusion True, so the formula is exactly the contrapositive of negation test.

Everything works well using this formula and I have good accuracy on these SA and NA questions. However, recently I encountered several questions that seem to be the outliers. NA is somehow conflated with SA, so I’m very confused. Would be very appreciative if anyone could help me sort this out

For example, here the premise is sugar—> insulin—> tryptophan enter brain—> increase serotonin
Conclusion: sugar—>mood elevation

It’s quite clear that the gap is increase serotonin—> mood elevation, and the correct answer D states the exact thing. If this is a SA question, then D is a no-brainer. However, when this turns out to be a NA question, I stopped and hesitated for a while. I still choose the correct answer because other options are far from correct, but I don’t understand how D logically works as a NA.

How does “sugar—> mood elevation”(conclusion true) lead to “increase serotonin—> mood elevation” (the NA)? What if there are other ways that causes the “sugar—>mood elevation” chain? Also, if we apply the negation test, increase serotonin doesn’t necessarily lead to mood elevation, it doesn’t undermine the conclusion. Sugar may still finds its way to connect to mood elevation in the end (perhaps through other channels and mechanism)

[YiW958]

I have the same question with you. I though D is Sufficient Assumption. But the Question type is Necessary Assumption Question.
So why a SA answer be the correct choice for a NA question??

Can a SA answer be the correct choice for a NA question too?

When I’m reading Loophole, the book suggests SA—>Conclusion True—>NA, so I thought NA should be sth. justified by a valid conclusion, not something that fills the gap between premise and justify/validate the conclusion (this is exactly what SA should do).

This formula is also proven by the negation test widely used to solve NA questions. Negation test states that ~NA—>~Conclusion True, so the formula is exactly the contrapositive of negation test.

Everything works well using this formula and I have good accuracy on these SA and NA questions. However, recently I encountered several questions that seem to be the outliers. NA is somehow conflated with SA, so I’m very confused. Would be very appreciative if anyone could help me sort this out

For example, here the premise is sugar—> insulin—> tryptophan enter brain—> increase serotonin
Conclusion: sugar—>mood elevation

It’s quite clear that the gap is increase serotonin—> mood elevation, and the correct answer D states the exact thing. If this is a SA question, then D is a no-brainer. However, when this turns out to be a NA question, I stopped and hesitated for a while. I still choose the correct answer because other options are far from correct, but I don’t understand how D logically works as a NA.

How does “sugar—> mood elevation”(conclusion true) lead to “increase serotonin—> mood elevation” (the NA)? What if there are other ways that causes the “sugar—>mood elevation” chain? Also, if we apply the negation test, increase serotonin doesn’t necessarily lead to mood elevation, it doesn’t undermine the conclusion. Sugar may still finds its way to connect to mood elevation in the end (perhaps through other channels and mechanism)