Q22 - In 2005, an environmental group

[ManhattanPrepLSAT1]

Question Type:
Flaw

Stimulus Breakdown:
The argument concludes that the study proves that regulation banning PCBs was effective in reducing harm from human exposure. This comes from the data showing that younger subjects had much lower levels of PCBs.

Answer Anticipation:
However, the arugment began by admitting that no scientifcally valid inferences could be drawn from the study because of the small sample size. The argument then turns around and procedes to draw inferences from the study!

Correct Answer:
(A)

Answer Choice Analysis:
(A) is correct. The argument can't have it both ways. If no scientificly valid inferences can be drawn from the study, then the conclusion contradicts a premise of the argument.

(B) attacks the wrong causal relationship. The issue isn't what effects were caused by chemicals, but what caused the reduction in chemicals.

(C) misidentifies the nature of the evidence in the argument. The argument does have positive supporting evidence.

(D) provides an impossible alternative to the one presented in the argument. Reducing the exposure to PCBs humans confront is not a realistic cause of regulation banning the use of PCBs. One necessary precedes the other.

(E) is out of scope. The issue is the level of exposure and what is responsible for the reduced exposure to PCBs. The issue of damage from such exposure is another idea altogether.

Takeaway/Pattern: Reasoning: Causation

#officialexplanation

[seychelles1718]

What role does the statement "scientifically valid inferences could not be drawn from..." plays in the argument?

I got this question wrong because I only focused in the main conclusion and the supporting premise for the conclusion and thus totally ignored the part that the author says valid inferences are impossible. I usually consider sentences where the author shows concessions (which usually starts with "although" "even though", "despite" ) less important to the argument core so tend to pay less attention to.

Also, I picked E because I erroneously thought "detrimental effects on human health" as equal to high PCB levels. I thought the argument overlooked the possibility that the test results do not accurately represent PCB levels in the subjects as it might take several years for PCB levels to be fully/accurately represented and the actual levels could be much higher.

[ohthatpatrick]

The role it plays is, "The secret to getting this one right".

Your instincts are sound, but just because we're used to filtering out filler doesn't mean that we don't occasionally get surprised to find out that some of the filler was valuable.

A lot of Flaw questions are just testing our listening skills. They want us to hear when an author changes topic, sounds too extreme, or fails to respond adequately to someone else's concern.

In this case, they want us to hear, "Aren't you contradicting yourself?"

In regards to (E), the level of something in your blood ≠ detrimental effects.

So, we can't say that (E) gives us a way of saying "maybe this chemical just hasn't yet revealed itself in the younger people".

The author tells us in the 1st sentence that PCBs are "toxic chemicals", so it's also untrue to say he's FAILED TO CONSIDER that PCBs can have detrimental effects on human health.

As an analogy, there's a big difference between cops seeing that levels of alcohol in my blood are currently beyond the legal driving limit and cops considering the possibility that alcohol consumption may have long term negative effects on my health.

[MingL143]

If you prephrase before going to answer choices, for example: " The author fails to consider the possibility that there were other effective method to prevent younger subjects to be affected by PCBs." "The argument takes a mere possible correlation to a causation.", then D seems a correct one.

[ohthatpatrick]

You're correct that the author makes a narrow causal assumption that "the regulations banning PCB's [caused] the reduction in human exposure to the chemicals."

In doing so, she fails to consider all other possible explanations for why the younger subjects had lower levels of PCBs.

So if (D) said
"takes something to be the cause of a reduction when there could be some other cause for the reduction"
it would be a correct answer.

(D) is an answer that says "Maybe it's reverse causality".
The regulation banning PCBs isn't what caused there to be less human exposure to those chemicals.
The fact that there was less human exposure to those chemicals is what caused the regulation banning PCBs.

? ? ? That doesn't seem like a good objection.

It doesn't make much sense to say "we noticed that these chemicals weren't as much of a problem anymore, so we decided to make some regulations banning them."

Make sure you take the time to match up the generic language in these answers with the specifics of the argument so that you can test their validity: "the argument takes the regulations banning PCB to be the cause of the PCB reduction, when the regulations banning PCB could have been an effect of that reduction".