Q4 - In a study of patients

[Shiggins]

The argument's conclusion is that peppermint makes insomniacs worse.

The evidence is that those who were given peppermint had more difficulty falling asleep than those who had the orange scent

I just want to make sure that I chose B for right reasons.

B weakens the argument bc it shows a flaw in the process of how they obtained thier results. If they gave it to insomniacs with the same problems then it would be ok.

But since the groups were split, those with mild were given the orange and the others were given peppermint, this constitutes a flaw in their method.

[ohthatpatrick]

What does the Question Stem tell us?
Weaken

Break down the Stimulus:
Conclusion: Smelling peppermint makes insomnia worse.

Evidence:
insomniacs who smelled P were more likely to struggle with sleeping than were insomniacs who smelled BO
+
BO doesn't make falling asleep easier

Any prephrase?
Provide an alternate reason why peppermint smellers has a harder time falling asleep, or make it less plausible that peppermint caused more sleep difficulties.

Answer choice analysis:
A) Out of scope because the conclusion is only about people who have insomnia.

B) Provides an alternate reason why peppermint smellers had a harder time: they had more severe cases of insomnia to begin with

C) Has no effect -- it feels like it's weakening the experiment by telling us the participants were aware they were being studied, but their awareness doesn't help us explain why there were different results for peppermint vs. bitter orange.

D) Has no effect -- it's incredibly weakly worded ("some" = at least one), and it doesn't differentiate between peppermint patients and bitter orange patients, so it tells us nothing informative

E) Could strengthen or weaken, depending on whether you assume that peppermint = "pleasant scent" ... and if you assumed that peppermint WAS a pleasant scent, you still wouldn't know whether pleasant scents dramatically affect the degree of insomnia by making it better or worse (so you don't know whether this strengthens or weakens the argument).

The correct answer is B.

Takeaway/Pattern: The most common function of a Weaken answer for a Correlation -> Causation argument is to explain the correlation in a different way. This is a popular alternate explanation: two different groups of research subjects are being compared; we're assuming they are essentially identical people; but in reality there is a significant difference between them that could be the real causal factor. (They have different "base rates" / "initial reference points")

[kky215]

You nailed it.

If you're trying to strengthen a causal argument, then you'd like to know that other possible causal factors were controlled for.

So it's always possible to weaken a causal argument by pointing out some uncontrolled variable that might REALLY be the important causal factor.

Nice work.

A) is out of scope because the conclusion is only about people who have insomnia.

C) has no effect -- it feels like it's weakening the experiment by telling us the participants were aware they were being studied, but their awareness doesn't help us explain why there were different results for peppermint vs. bitter orange.

D) has no effect -- it's incredibly weakly worded ("some" = at least one), and it doesn't differentiate between peppermint patients and bitter orange patients, so it tells us nothing informative

E) could strengthen or weaken, depending on whether you assume that peppermint = "pleasant scent" ... and if you assumed that peppermint WAS a pleasant scent, you still wouldn't know whether pleasant scents dramatically affect the degree of insomnia by making it better or worse (so you don't know whether this strengthens or weakens the argument).

Is this an example of "base rate fallacy"?

[ohthatpatrick]

I've never heard that term before, but given the context, I'm assuming "base rate fallacy" means "the assumption that all subjects in an experiment entered the experiment with a similar base rate for whatever is being measured"?

In which case, yes.

[smsotolongo]

For us dummies you mean "all things being equal?"

[tommywallach]

I believe so.

[zcxlwj]

Hello - Doesn't (C) suggest the study was faulty, and so any conclusions drawn were not necessarily reliable (thus weakening the argument)? This reminded me of PT44, S2, Q20 impulsive behavior.

Since the conclusion said "peppermint makes insomnia worse", I crossed out (B) as, if anything, it seemed to suggest peppermint was not helpful to treating insomnia, and not necessarily making it worse.

Could anyone help me understand the issues with my reasoning for either answer choice? Thanks!