If human testimony is so unreliable, then why is it used in a court of law?
Because juries tend to buy it, and because often there's no other choice.
The unreliabilitiy of human testimony is well-known. Lawyers aren't out to find the truth, they're out to convince a judge or jury.
From
HOW RELIABLE IS EYEWITNESS TESTIMONY?:
quote:
In fact, contrary to popular opinion, circumstantial evidence is often extremely reliable. Blood of the victim that makes a DNA match with blood found on the defendant's clothing, credit card records that place the defendant at the scene of the crime, and ballistics analysis that shows a bullet removed from the victim to have been fired from the defendant's gun are all forms of circumstantial evidence. Yet, in the absence of a credible allegation of police tampering, such evidence is usually highly reliable and informative.
At the same time, numerous psychological studies have shown that human beings are not very good at identifying people they saw only once for a relatively short period of time. The studies reveal error rates of as high as fifty percent a frightening statistic given that many convictions may be based largely or solely on such testimony.
See also
Eyewitness Memory is Unreliable and, of course,
this famous test.
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