Q3 - A study of the dietary habits

[ohthatpatrick]

Question Type:
Flaw

Stimulus Breakdown:
Conclusion: If you have more galactose than the body can process, it's carcinogenic.
Evidence: There's a correlation between [not having enough enzyme to process galactose] and [cancer].

Answer Anticipation:
This is a correlation to causality argument, for which we're always asking ourselves two questions:
1. Is there some OTHER WAY to explain the background data?
2. Is the AUTHOR'S WAY of explaining it PLAUSIBLE?

So is there some other way to explain why the people WITH the ability to process galactose DON'T have cancer, and the people WITHOUT the ability the process galactose DO have cancer? Or is there some way to shoot down the plausibility of how an overdose of galactose could possibly cause cancer?

Correct Answer:
D

Answer Choice Analysis:
(A) It's too demanding to expect that the diets were the same in ALL other respects. We would like to know if there is some OTHER difference in the two groups that could explain the divergent cancer rate. But this wouldn't be a strong objection, because in the real world we know it would be pretty impossible for a study to maintain IDENTICAL dietary habits for two different groups, for five whole years.

(B) Whether or not the author goes one step farther to make a recommendation is beyond our purview. We're trying to criticize how he arrived at the conclusion, not criticize him for failing to go somewhere else after that.

(C) The author is saying "I think X can cause cancer", not "I think X is the ONLY THING that can cause cancer". So this objection isn't relevant.

(D) YES! Here's an OTHER WAY to explain the background data. If the cancer came first and THEN they lost their ability to process galactose, then obviously the 2nd thing wasn't the cause of the 1st thing.

(E) We don't care whether it was super low or absent entirely. The only salient idea for this argument is that "it was low enough to keep the body from processing galactose".

Takeaway/Pattern: On causal arguments, the most common type of answer is one that deals with some OTHER WAY to explain the background data. The two most common "other ways" are REVERSE CAUSALITY (maybe causality flows in this correlation the opposite way from the way the author was thinking), or SOME THIRD FACTOR (maybe there is some other trait at play here that is *really* the causal factor).

#officialexplanation

[lt2ncav]

I got this one correct just because the other ACs just didn't sound right. I still need some help wrapping my head around what exactly makes D right. Can someone spell this one out for me. Thanks!

[quinn.nguyen27]

OP, I think you posted the wrong question. Question 3 is about dietary habits. Question 4 is about chemical pollutants. Anyway, here's the break down for Q3 dietary habits:

A) Tempting because it holds all factors equal, but this answer goest to the extreme by the diet has to be the exact same (ie. everybody eats same portion of carrots, meats, etc.) Participants should generally have the same diet but definitely not the exact same.
B) we're trying to evaluate a causal claim; there's no proposal we're considering
C) okay, so there are other known causes. Can't this be a cause as well? The possibility of other causes does not weaken this low levels of galactose as a potential cause
D) Classic reversal of cause and effect. Argument shows correlation of low levels of galactose and cancer.

There are 3 ways to explain a correlation:
1.A causes B
2.B causes A
3. Third factor causes both
Argument assumes #1, while #2 could also explain the correlation.

E) we don't care about lacking enzymes entirely. The issue are the levels of enzymes.

[tommywallach]

Hey Guys,

Quinn, your explanation is great! This is a classic causation/correlation error. Our core looks like this:

Conclusion: Too much galactose is carcinogenic
Premise: People without galactose-processing enzyme have cancer

I've simplified that, but it's the point. Then, as Quinn said, the problem is that it could be that cancer causes the enzyme problem (or some third issue could be causing both cancer and the enzyme problem).

Great work!

-t

[WaltGrace1983]

I would like to add that another problem with (A) is that it still fails to show anything regarding causation. Sure, more correlation is good, but showing possible causation in a correlation/causation stimulus is much much better. Even if we were to say that EVERYTHING, other than the yogurt enzyme, was the EXACT same between the two groups, we still couldn't really show that the low yogurt enzyme levels caused cancer. It would still be just as likely that cancer caused the low yogurt enzyme levels. Tricky for sure!

As for (C), we are specifically trying to disprove that the low yogurt enzyme levels cause cancer. The stimulus is not saying that this is the ONLY cause of cancer. It is merely introducing the low yogurt enzyme levels as a potential cause, a sufficient condition if you will.

As for (E), we don't need to know anything more about the relative "lowness" of yogurt enzyme levels. We know that low yogurt enzyme levels are correlated with cancer. We don't need to know anything about LOWER yogurt enzyme levels, this would just strengthen a premise I suppose.

[mggallag]

Thanks, everyone.

Is this a weaken or identify the flaw question with the language: "of the following which one constitutes the strongest objection to the reasoning in the argument"?

[seychelles1718]

I understand the explanations above but doesnt A weaken the argument slightly, but just not the STRONGEST objection among 5 choices? Because the argument is based on a comparison, I believe to conclude on causality without showing that the two groups being compared to each other is a flaw. The argument definitely fails to establish the two groups are comparable in all other aspects except the levels in the enzyme. IMHO A is wrong not because it can't weaken at all but rather because it doesn't address the causal flaw, which is the most important thing in this argument.

[ohthatpatrick]

I think you're right. As long as we haven't perfectly controlled for all other factors, we can't be 100% sure about proving a causal link.

So (A) is an objection that introduces at least some doubt.

But because it's worded in such an extreme fashion, "The dietary habits were the same in ALL other aspects", it's really not talking about a realistic demand we could ever have (for two groups being studied over a course of five years).

If we said, "Hey, author, the two groups were not IDENTICAL in all other dietary aspects", the author (and reasonable people) would be like, "True, but that's pretty much impossible, so where does that objection get us?"

[andrewgong01]

I fell into the trap of choosing "A", the extreme answer choice that calls for everything to be equal. However, if A had been worded more specfically like :

"It fails to account for the fact that the two groups of people live in different environment; one in a polluted city and the other in the country side "
or
"the two groups consumed different amounts of processed foods which could also contain cancerous stuff"


would we say A is correct because instead of calling for EVERYTHING to be the same it is now pointing out one factor is not the same but this one factor could be an alternative way of explaining something and is important?Under the old paradigm of the original "A" calling for a blanket equality between the two groups included insisting on factors that may not be relevant to cancer which seems to be the issue with why "A" is a weak weakener.

[ohthatpatrick]

Yes, it could be a correct answer by either naming a specifically relevant thing they should control for or just by hedging the wording more, like
"Fails to establish that the two diets were relevantly similar"

[XiduoH792]

I'm still a little bit confused about D. Is it possible that even the cancer causes low levels of the enzyme, the excessive galactose cannot be processed may still be carcinogenic?