It has been proven that the lie detector can be fooled.

Question

It has been proven that the “lie detector” can be fooled. If one is truly unaware that one is lying, when in fact one is, then the “lie detector” is worthless.

Without contradicting his or her own statements, the author might present which of the following arguments as a strong point in favor of the lie detector?

A. The methodology used by investigative critics of the lie detector is itself highly flawed.

B. Law-enforcement agencies have purchased too many detectors to abandon them now.

C. Circumstantial evidence might be more useful in a criminal case than is personal testimony.

D. The very threat of a lie-detector test has led a significant number of criminals to confess.

E. People are never “truly aware” that they are lying.

Thonereturns · Answer

D

The q stem ask to identify argument which is in favor of using lie detectors, w/o contradicting the statement given.

A. The methodology used by investigative critics of the lie detector is itself highly flawed. -- Doesnt favor using LD

B. Law-enforcement agencies have purchased too many detectors to abandon them now. -- Not favoring LD use

C. Circumstantial evidence might be more useful in a criminal case than is personal testimony. -- Infact arguiing against LD use

D. The very threat of a lie-detector test has led a significant number of criminals to confess. -- So even if LD dont work perfectly, their mere use gives positive result. This is our ans.

E. People are never “truly aware” that they are lying.

crimson_noise · Answer

I may be wrong, but if someone does not know they are lying, how will threat of a lie detector have any effect on them?

Harshita2003 · Answer

Hey! I think you're referring to Option E here. The thing is, it assumes in general that people are never "truly aware" that they are lying. While in some cases it might be true, that doesn't happen in every case.

CareerLauncherMBA · Answer

The question is about reasoning from the author's perspective. The author claims that if someone truly believes what they are saying—even if it is actually false—the lie detector (polygraph) won’t be able to expose the lie. The author’s argument is that the polygraph is flawed because it works by detecting physiological changes (like stress) usually associated with knowingly lying. If the speaker is unaware, those changes may not occur. 
 
Let’s analyze each option to determine which the author could endorse as a strong point in favor of the detector—without contradicting their own logic:

A. The methodology used by investigative critics of the lie detector is itself highly flawed.    
 This is an attack on critics, not a point in favor of the machine’s value. It does not address whether the detector itself is effective.

B. Law-enforcement agencies have purchased too many detectors to abandon them now.    
 This is an argument from sunk costs and does not constitute a logical point in favor of the detector’s effectiveness.

C. Circumstantial evidence might be more useful in a criminal case than is personal testimony.    
 This compares the value of different types of evidence, but says nothing about the lie detector specifically.

D. The very threat of a lie-detector test has led a significant number of criminals to confess.    
 This suggests that, even if the device itself is not perfect, its mere use has practical benefits—criminals confess rather than face the test. The author could endorse this as a strong practical point in the device’s favor, because its value is independent of its technical accuracy, and this does not contradict the author’s initial argument about its limitations.

E. People are never “truly aware” that they are lying.    
 This would contradict the author’s premise that sometimes people can be unaware that they’re lying. 
 
 Correct Answer: D  
The very threat of a lie-detector test has led a significant number of criminals to confess.

Detailed Explanation: 
The author’s logic rules out E (it contradicts the author’s premise). A, B, and C are irrelevant to the lie detector’s practical effectiveness. Only D offers a legitimate, non-contradictory defense: even if the machine isn’t foolproof for technical reasons, it has real-world utility because it can indirectly lead to confessions. This supports the use of the detector without requiring it to be flawless, thus not contradicting the author's central claim.

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It has been proven that the lie detector can be fooled.

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It has been proven that the lie detector can be fooled.

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