Tuesday, September 23, 2008

Acting White: A Hardlook at Eyewitness Testimony

As the Supreme Court considers the fate of Georgia death-row convict Troy Davis, perhaps America will consider this expert testimony regarding the accuracy of eyewitnesses.

"The conventional wisdom, particularly among non-lawyers, is that circumstantial evidence is generally less reliable than eyewitness testimony. People sometimes say that a case is "only circumstantial" to mean that the evidence is weak. A strong case, according to this view, includes the testimony of an eyewitness.

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.

These studies show further that the ability to identify a stranger is diminished by stress (and what crime situation is not intensely stressful?), that cross-racial identifications are especially unreliable, and that contrary to what one might think, those witnesses who claim to be "certain" of their identifications are no better at it than everyone else, just more confident...more"

Michael C. Dorf is Vice Dean and Professor of Law at Columbia University.

James C. Collier


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Anonymous said...

nice blog!

Anonymous said...

The simple fact is that polygraph (lie detector) tests are much more reliable than eyewitness testimony; and yet eyewiteness testimony is embraced by the courts and polygraph results are excluded from evidence.

This, more than anything else, reinforces that the prosecutorial side of the criminal court system is more interested in convictions than justice.