Kevin Drum of Calpundit makes a convincing argument about why photographic lineups as well as police interrogations should be videotaped:

"Eyewitness testimony is notoriously untrustworthy and witnesses in criminal trials routinely convince themselves in retrospect that they were always sure that was the guy. But juries might feel differently if they saw videotape showing exactly what those witnesses really thought the first time around, and how that changed the second and third times around and then again in court. Like the use of DNA evidence, there's simply no reason to object to videotaping. It doesn't coddle criminals, it just forces police to focus on making sure they catch the right person, not just any person."

What Kevin is describing is termed "confidence inflation" or "confidence growth" by the psychological researchers in the field. It describes those cases where the witness becomes more certain of his or her opinion over time. Often this is due to repeated interviews by the police in which the witness' prior identification, even if tentative, is reinforced.

Videotaping is one way to judge how certain the witness was at the time of their original selection. Another is for the person conducting the lineup to ask the person who makes a selection "How certain are you?" right away and write it down.

For more on this, here is an article we wrote on the subject called Could This Happen to Your Spouse or Child? Wrongful Convictions and Eyewitness Testimony

Law enforcement is gradually changing the ways it interviews eyewitnesses to crime to conform to the findings of psychological researchers in the field. For example, the Department of Justice, through its reasearch arm, the National Institute of Justice has released a publication Eyewitness Testimony: A Guide for Law Enforcement.

PBS's Frontline had an excellent show on the topic, What Jennifer Saw. The website is still up and you can read more about the topic there.

For more, check out the websites of Professors Elizabeth Loftus and Gary Wells, two of the nation's leading experts in the field of memory and eyewitness evidence.