Truth,lies, and technology Throughout history, mankind has searched for a foolproof way to detect lies.
Traditionally, lie-detection methods have been based on the fact that people worry about having their untruthfulness exposed, and that this anxiety causes measurable physiological changes.
For example, the world's first lie-detecting machine, invented in 1895, measured changes in the pulse rate and blood pressure of subjects being questioned.
The polygraph machine, invented in 1921, and which has become the standard method for detecting lies, continuously records changes in subjects' blood pressure, pulse rate, and rate of breathing.
But what the polygraph actually tests is whether a subject believes he or she is telling the truth, not whether the person's statements are in fact true.
It is a useful investigative tool that helps police verify information, but---despite common misconceptions----the polygraph is rarely used to determine a suspect's guilt or innocence.
Because undergoing a polygraph examination is voluntary, and because innnocent people are assumed to have little to fear from the machine, police can focus their criminal investigations to suspects who refuse to be tested.
In 1987, the FBI studied more than 20,000 polygraph examinations and determined that less than one percent were inaccurate.
In the 91 cases where results were eventually proved wrong, only 27 involved tests in which liars managed to outsmart the machine.
Despite this extraordinary degree of accuracy, the polygraph remains an object of controversy.
Critics claim the machine is hopelessly flawed because of its reliance on emotional responses, which can differ widely from person to person.
Many researchers today feel they can improve on the polygraph by targeting the source of the lie: the brain.
One such brain-scanning technique, called "brain fingerprinting," tracks a signal that the brain emits when it perceives something familiar.
In other words, it reads people's memories.
The idea of using knowledge stored in the brain to determine guilt or innocence is not new.
In the Late 1950s, David Lykken developed the Guilty Knowledge Test, in which suspects are asked multiple-choice questions to see how they react to specific details that only the person who committed the crime could know.
The challenge for researchers today is to develop biologic measures of subjects' reactions that, unlike the polygraph, are unaffected by emotional responses.
Some have proposed tracking eye movements to see whether a subject recognizes other criminals or victims.
Another potential method is to measure response times, as research has indicated that people take longer to respond to a question when they are lying.
Would a foolproof lie detector truly benefit society?
The answer is obvious------ just ask law-enforcement officials,crime victims, and the wrongfully accused.
For the sake of these advocates of truth, the search for this elusive technology goes on.
46
According to the passage, the polygraph machine
1 is often used during questioning to determine a subject's guilt or innocence.
2 is preferred by police because it eliminates the anxiety caused by earlier machines.
3 is the first lie-detecting machine to measure a subjict's blood pressure
4 is still the most common method of lie detection.
正解 4
この文章によると、ポリグラフ式嘘発見器は
うそを見破るための依然として最も一般的は方法である。