Q1 - On the Caribbean island of Guadeloupe

[ohthatpatrick]

Question Type:
Strengthen

Stimulus Breakdown:
Conclusion: Eating these fruits causes aytpical Parkinson's.
Evidence: There was a correlation between eating the weird fruits and having atypical Parkinson's.

Answer Anticipation:
This is a classic Correlation to Causality argument. The two available pressure points are
1. Plausibility of author's causal story
and
2. Other causal stories.

Answers in the form of #1 would be like "these fruits have a certain chemical that can interact with Parkinson's", or "the more of this fruit people ate, the more atypical their Parkinson's got" or "Parkinson's does not have an entirely genetic basis; it can be affected by dietary habits".

Answers in the form of #2 would be something like "the atypical Parkinson's came first, and THEN they started eating these fruits (maybe those fruits are suggested as remedies for people with atypical Parkinson's)" or "the same genetic condition gives way to atypical Parkinson's and funky fruit cravings".

Since we're doing a strengthen question, we either want to increase the plausibility of the author's story or rule out the possibility of a different story.

Correct Answer:
A

Answer Choice Analysis:
(A) Yup. Classic "covariation" answer (the idea that cause/effect go hand in hand. More cause, more effect. No cause, no effect)

(B) We don't care if the healthy people have tried these weird fruits at least once in their lives.

(C) This is a Weaken idea, again from the world of "covariation" (no cause / effect).

(D) This drifts towards Weakening. If these fruits really caused Parkinson's, we'd expect the people who eat the most of these fruits to have Parkinson's, not to be healthy.

(E) This offers a reason for why people regularly eat these fruits but doesn't connect in any way to whether these fruits cause Parkinson's.

Takeaway/Pattern: Weaken questions are more likely to deal with a #2 (an alternate story for the same correlation), while Strengthen questions are slightly more likely to have a #1 type answer. The most common form for this is the "Control Group" answer: people not exposed to the cause do not see the effect (or the relative version of that -- people exposed LESS to the cause experience LESS of the effect).

#officialexplanation

[aznriceboi17]

Putting the answer choices aside for a moment, the researcher's reasoning struck me as flawed when I read it because she hasn't provided any evidence of a casual relationship between eating the tropical fruits (maybe having atypical Parkinson's causes one to have cravings for the tropical fruit -- who knows?).

After a first read, none of the answer choices seemed to try to fix this lack of evidence for a casual relationship. So my next step was to try to look for something that would at least make the correlation between eating tropical fruits and Parkinson's stronger -- so this means addressing why the 10 healthy people don't have Parkinson's despite eating the tropical fruit. This led me to choose D, my reasoning (a bit far-fetched) being that the huge quantities of tropical fruit being consumed somehow negated the effects of whatever property it was that caused Parkinson's.

Can someone explain how A strengthen's the argument? One reason why I didn't choose it was because it only mentions the symptoms stopped getting worse/abated. In my mind there is a distinction between something causing a person to contract Parkinson's, and something causing the symptoms of Parkinson's to get worse. Maybe something else is the root cause of those 35 patients getting Parkinson's, and the consumption of the fruits only shows up in the severity of the symptoms.

As I see it, the original argument boils down to:

all 35 people with Parkinson's ate fruit + 10/65 healthy did ---> fruit causes Parkinson's

while the argument in A is:

the 35 stopped eating fruit and then saw symptoms improve ---> fruit causes Parkinson's

neither of which conform to the patterns of reasoning I've seen/seem sound.

What am I missing here? Thanks!

[fmuirhea]

You are correct in your assessment that the argument is flawed because it takes correlation to imply causation. Are you being thrown by the word "strengthen" in the question stem? If an argument can be either strengthened or weakened, it implies that it is flawed in some way - if it weren't, if it were already air tight, then you wouldn't need to strengthen it! Strengthen/weaken questions are closely related and revolve around the assumption/flaw in the argument.

There are some standard ways to strengthen causal arguments (with complementary weakeners):

1. rule out an alternate cause (including reverse causation)
2. give another example of the alleged cause leading to the alleged effect
3. show that when the alleged cause is absent, so too is the alleged effect

(A) falls into the third category. If symptoms are alleviated (or disappear completely) when the fruits are not consumed, it gives us some reason to believe there is a causal connection. It doesn't prove the conclusion, but strengtheners don't need to be so absolute. As you mentioned, your reasoning for (D) is a little too far-fetched, beyond what the LSAT would call a reasonable assumption.

[ohthatpatrick]

Fantastic explanation.

To the original poster, I want to make sure you're comfortable with how this reasoning DOES strengthen causality:

the 35 stopped eating fruit and then saw symptoms improve ---> fruit causes Parkinson's

Say we were testing a new medication, X, and some of the test subjects started complaining of blurry vision. We might think, "jeez, is X causing the blurry vision? Did they have blurry vision PRIOR to going on X?"

We might take them off X for a while to see whether it made a difference. If we took them off X and they stopped having blurry vision, would we be likely to conclude that X really WAS the factor that was causing their blurry vision?

Yes! That's why (A) is very relevant to assessing causality. Hope this helps.

[aznriceboi17]

Hi everyone, thank you for the helpful responses. Method 3 of strengthening causal arguments is something helpful that I'll have to keep in mind, and D now does look too far-fetched to me.

Having said that, I have a much stronger preference for the example ohthatpatrick gave with medication and blurry vision. That one is much less likely to cause confusion over a distinction between causing a disease and exacerbating its symptoms -- a point I'm still stuck on.

For example, if a person has a cold then exercise can exacerbate some of the cold symptoms (such as coughing). If a person with a with a cold were to stop all exercise, their symptoms might abate and might even disappear entirely (if their cold was very mild to begin with). But no one would argue that exercise causes a person to get a cold.

Maybe I'm making too much of this...

[ohthatpatrick]

I feel ya. Just remember that correct answers to Strengthen and Weaken will never PROVE or REFUTE anything. So there's still plenty of room to make your objection. But it does ADD plausibility to a causal hypothesis to show that when a certain stimulus is taken away, certain effects begin to disappear.

The example you're giving of exercise exacerbating cold symptoms but clearly not causing a cold is a great example of why "something that causes symptoms to get worse" does not PROVE "that something is the underlying cause of the illness".

But it COULD be the cause. Not getting enough sleep might exacerbate the symptoms AND be the root cause of getting a cold.

The idea that "what you're eating" could be the cause of an illness is plausible enough that we can consider a hypothesis involving that idea to be strengthened, even though the hypothesis is far from proven true.

[aznriceboi17]

Thanks for the response -- that definitely helps. I guess I'll have to improve my ability of judging whether a potential answers adds enough plausibility to be a good candidate for the correct answer.

[kjsmit02]

On this PT, I had originally chose (A), but switched my answer to (E). While I understand the arguments for (A), I still see (E) as strengthening the argument even more. (E) "The fruits have essential vitamins that aren't contained in other foods eaten by residents of Guadalupe". I took the vitamins unique to the fruits to be the actual cause of the atypical Parkinson's, and as nothing else eaten by the residents in Guadalupe could have these vitamins, the fruits alone are the only items that could have caused the atypical Parkinson's, thus ruling out alternate causes and strengthening the argument. Essentially: Fruits------> Unique Vitamins--------->Atypical Parkinson's. Looking at (E) though, I see that it may have been a stretch to assume that these essential vitamins, not contained in other foods, caused the atypical Parkinson's through the fruits. Or maybe the use of "residents" vs. "patients" (wouldn't patients have to be residents, at least temporarily?). However, if true, (E) would still seem more likely to strengthen the argument more than (A) in my opinion. While (A) gives us evidence that the absent of the cause removes the symptoms, this only does so for "many" patients (how many? 3 of 35? If so, couldn't Alt. Causes be responsible?). Can anyone help me see where I've erred in my reasoning?

[DaisyA495]

Putting the answer choices aside for a moment, the researcher's reasoning struck me as flawed when I read it because she hasn't provided any evidence of a casual relationship between eating the tropical fruits (maybe having atypical Parkinson's causes one to have cravings for the tropical fruit -- who knows?).

After a first read, none of the answer choices seemed to try to fix this lack of evidence for a casual relationship. So my next step was to try to look for something that would at least make the correlation between eating tropical fruits and Parkinson's stronger -- so this means addressing why the 10 healthy people don't have Parkinson's despite eating the tropical fruit. This led me to choose D, my reasoning (a bit far-fetched) being that the huge quantities of tropical fruit being consumed somehow negated the effects of whatever property it was that caused Parkinson's.

Can someone explain how A strengthen's the argument? One reason why I didn't choose it was because it only mentions the symptoms stopped getting worse/abated. In my mind there is a distinction between something causing a person to contract Parkinson's, and something causing the symptoms of Parkinson's to get worse. Maybe something else is the root cause of those 35 patients getting Parkinson's, and the consumption of the fruits only shows up in the severity of the symptoms.

As I see it, the original argument boils down to:

all 35 people with Parkinson's ate fruit + 10/65 healthy did ---> fruit causes Parkinson's

while the argument in A is:

the 35 stopped eating fruit and then saw symptoms improve ---> fruit causes Parkinson's

neither of which conform to the patterns of reasoning I've seen/seem sound.

What am I missing here? Thanks!

The stimulus doesn't have to provide us with any evidence of a causal relationship between the two terms. The stimulus could be a single line sentence stating "cats cause cancer" with no other evidence backing it up, and our job still remains the same: when strengthening a cause-effect, we either:

1. Prove the effect to be present when the cause is present
2. The effect to be absent when the cause is absent
3. Eliminate an alternative explanation (like your example of how atypical Parkinson's could cause one to have cravings for the tropical fruit; one relatively "weak" strengthening AC may be that having atypical Parkinson's does NOT cause one to have cravings for the tropical fruit)

So your approach is correct in trying to strengthen the correlation between the fruit and the Parkinson's, but I think you mistakenly focused on the 10 healthy adults rather than the 35 unhealthy adults. My interpretation of the "cause-effect" in this situation is not that "fruit always causes Parkinson's 100% of the time the moment you eat them regularly"; otherwise, it would be confusing why the 10 healthy adults are able to eat them yet not have Parkinson's. I interpreted the stimulus to have some leeway in that regard. Maybe the 10 healthy adults who regularly ate the fruit may eventually get Parkinson's later in life. Regardless, the argument still stands: "35 adults regularly ate fruit, and they contracted Parkinson's." We should ignore what the stimulus tells us about the 10 healthy adults because that's not what the conclusion is talking about. All the conclusion is saying is that "fruits cause Parkinson's." Concentrating on the 10 adults who ate the fruits yet did not contract Parkinson's is as irrelevant to the matter as would be if the stimulus told us "There is a single special person who ate exorbitant amounts of the fruit but has a magical gene that prevents them from ever getting sick", and we focused on that.

So, the reason why D is incorrect is because it shows the cause but not the effect. This actually weakens the argument. D essentially says "Eating the fruits does not necessarily cause Parkinson's", and that is the opposite of what we want. We want an answer choice that says "eating the fruits causes Parkinson's", or "not eating the fruit causes Parkinson's to go away", which is what A says.

[mswang7]

Premises: 35 parkinsons patients, 100% of them ate these fruits
65 healthy adults, only 10% ate these fruits
Concl: Fruits cause parkinsons
Prephase: Something thats rules out parkinsons casuing the fruit eating.
This is a classic 2 things happen together, therefor A must cause B. Ruling out B causes A will help us prove that

A. This strengthens since the removing the fruits are improving the parkinsons health conditions
B. Irrelevant
C. Weakens as well - example of symptom without the alleged cause (parkinsons but no fruit)
D. Weakens, if the 10 healthy adults who did consume the fruit consumed so much more (and fruit causes parkinsons) it seems to contradict the fact they are healthy/ without the disease
E. Out of scope/ doesn't discuss relation to parkinsons