Critical Reasoning

A researcher studying drug addicts found that, on average, they tend to manipulate other people a great deal more than nonaddicts do. The researcher concluded that people who frequently manipulate other people are likely to become addicts.

Which of the following, if true, most seriously weakens the researcher's conclusion?

A. After becoming addicted to drugs, drug addicts learn to manipulate other people as a way of obtaining drugs.

B. When they are imprisoned, drug addicts often use their ability to manipulate other people to obtain better living conditions.

C. Some nonaddicts manipulate other people more than some addicts do

D. People who are likely to become addicts exhibit unusual behavior patterns other than frequent manipulation of other people

E. The addicts that the researcher studied were often unsuccessful in obtaining what they wanted when they manipulated other people.

I could not understood why A is correct even I went through the answer.
Can someone explain in detail and in easy language?

What does manipulate indicate here? -> encouraging others to do same thing.

Evidence: Drug addicts manipulate others than non addicts do

Conclusion: If a person manipulates others, he/she is likely to become an addict.

Assumption: A person before becoming a drug addict manipulates others.

A. clearly tells that only after becoming addicts they start to manipulate others thereby weakening the conclusion.

Hi,

akhp77 wrote: I could not understood why A is correct even I went through the answer.
Can someone explain in detail and in easy language?

What does manipulate indicate here? -> encouraging others to do same thing.

You actually don't need to know what manipulate means here. Let's replace manipulate with say Trick. Now the stimulus states

1) The researcher found that:
Drug Addicts -> Trick (Manipulate) people more than nonaddicts

Based on this fact the researcher concludes that:
People who frequently trick (manipulate) other people -> are likely to become addicts

But, what if a person learns to trick people after he has become an addict. In other words, act of tricking people is the result of (follows) drug addiction.

If this were true, the researchers conclusion (people who trick are likely to become addicts i.e. drug addiction is the result of (follows) tricking people would be weakened and this is what choice A states.

Hope this helps.

T11

I got the choices between, A & D; although I understood A, but what I do not understand is that why answer choice 'D' is wrong? According to D, anyhow the likely to be addict does not manipulate others, so this could be correct too. OR, is it wrong because of the word 'frequent' ?

Cheers
A

+1 A

D is out of scope.

A the best choice

Why is the answer not D? In the given case, the author concludes that manipulative behavior causes people to become addicts. Thus, A causes B. The CR bible says that if we can show that there are other factors at play that cause B, and A is not the only one, then it undermines or weakens the argument. The choice D tells us that manipulative behavior is the not the sole reason for people becoming addict, i.e. A alone is not responsible for the cause of B. Can't we take such a reasoning to say that D indeed is the correct choice?
Help appreciated.

Why not D?

Conclusion: -> Manipulative people are likely to become drug addicts.

D. People who are likely to become addicts exhibit unusual behavior patterns other than frequent manipulation of other people.

So, it says that the people who are likely to become drug addicts have the manipulative behavior. ie people with manipulative behavior (and other patterns) become drug addicts. It doesn't rule out that manipulative people become drug addicts.

A, which says that people learn manipulating after becoming drug addicts, is clearly weakens the argument.