#23 - Safety expert: Conversing on a cell phone while

[Administrator]

Please post your questions below! Thank you!

[medialaw111516]

Got stuck between A & B and picked B, but still can't figure out why A is correct or B is wrong

[Claire Horan]

Hi MediaLaw,

Since this is an assumption question and you've narrowed it down to two choices, A and B, try using the Assumption Negation technique.

First, try A. IF we negate (A), we get: "Speaking to a driver during a difficult driving situation DOES NOT significantly increase the risk of an accident, EVEN IF the speaker is NOT providing helpful warnings." This attacks the conclusion that conversing on a cell phone is more dangerous, because this assumption attacks the main difference the author is positing between cell phone conversations and in-person conversations. This appears to be the right answer, but let's make sure by considering B, our other contender.

If we negate (B), we get: "A driver having a conversation with a passenger in the vehicle during a difficult driving situation IS substantially more likely to have an accident than is a driver who is not conversing during a difficult driving situation." This answer choice doesn't attack the conclusion because one of the safety expert's premises is that passengers will usually be quiet or helpful in difficult situations, while the person on the other end of the cell phone will do neither because he or she will be unable to recognize the difficult situation.

(A) passed the assumption negation technique, and (B) failed. (A) is indeed the right answer!

[medialaw111516]

Thanks Claire!

[ali124]

Hello.
I was just wondering whether the conclusion can said to be 100% valid based on the premises and necessary assumption (A). The stimulus says that passengers in vehicles will "usually be quiet for provide helpful warnings," and goes from this to conclude that conversing on cell phone while driving "is more dangerous" than conversing with passenger in the vehicle.

If there is still a chance that the passenger may not stop talking while driver is in diffcult driving situation, isn't it possible for that act to be as dangerous as talking on the phone while driving? If this is a possibiility, then can we conclude that cell phone conversations are still (100%) more dangerous than conversations with passengers?

This reasoning made me hesitate for all answer choices, and I would appreciate your clarification.
Thank you!

[James Finch]

Hi Ali,

No, a necessary assumption, aka the correct answer to an Assumption question, doesn't by itself prove the conclusion true. That's the job of a sufficient assumption, aka a Justify answer. The relationship the two types of assumptions have to the conclusion is one of sufficient or necessary conditions for it:

Justify AC True (SA) Conclusion True

If the justify answer choice is true, the conclusion must be true. Pretty straightforward. Where it gets a little trickier is with necessary assumptions:

Conclusion True Assumption True

This requires us to take the contrapositive to test necessary assumption answer choices, in a process we call the Assumption Negation test:

Assumption True Conclusion True

So we need to first negate our contending answer choices, then negate the conclusion and see if, when paired with the premises given in the stimulus, the negated assumption would logically lead to the negated conclusion.

In this case, the conclusion is that talking on a cell phone while driving is more dangerous than talking to a passenger while driving, with the premise being that being physically present leads passengers to be either quiet or even helpful when driving becomes dangerous, while someone on a cell phone won't know to react to dangerous driving conditions and continue talking. The logical gap that the stimulus needs to work is that talking during dangerous driving conditions is itself dangerous. This is almost certainly factually true, so it's an easy assumption for a test taker to make unthinkingly, but unless it's stated as a premise in the stimulus, it's an assumption being made.

(A) gives us this assumption, which we can test by negating to:

Speaking to a driver during dangerous situations does not increase the risk of an accident

which would then lead to the negated conclusion:

Conversing on a cell phone while driving isn't necessarily more dangerous than talking to a passenger while driving

Works perfectly, making it the correct answer.

Hope this clears things up!

[ali124]

Your explanations clarified so much! Thank you.

[ed]

Hello,
I'm wondering why E is incorrect. After reviewing the question again, it seems to me that A directly utilizes the scenario provided in the stimulus, whereas E adds in extra information (or twists the scenario in a different light); E might be a better answer for a question of the type "which of these is most strongly supported."

Does that analysis seem fair?

[Robert Carroll]

Ed,

Answer choice (E) is actually pretty opposed to the argument of the stimulus. It's saying that conversing on a cell phone is not more dangerous than something - but isn't the author's point to prove that it is more dangerous? Even if the author's argument could accept that conversing on a cell phone is not more dangerous than some activities, why would the author want to do that, much less have to assume it? The more dangerous it is, the better for the author.

That alone is actually enough to get rid of answer choice (E), but there's a detail in the answer that is also trouble. The author does not think that passengers are always distracting when they talk. Look at the last clause - the author is acknowledging that a passenger who provides helpful suggestions during difficult driving situations might help make the situation less dangerous, or at least not increase the danger. So the author is not saying "cell phones are more dangerous than a passenger talking, although a passenger talking during a difficult situation might be as dangerous." Instead, the author accepts that, in some cases, a passenger talking during a difficult situation can be less dangerous. So when answer choice (E) makes it seem like a cell phone conversation is not more dangerous than a talking passenger, that conflicts with what the author wants to be true - that cell phone conversations are dangerous, and talking passengers are sometimes not dangerous, and even helpful.

Robert Carroll

[ashpine17]

What happens if D is negated? Does that mean talking with a passenger is more or less distracting than talking to someone on the phone?