Natty Shafer Law

Utah lawyer for criminal and immigration cases

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Juries Rarely Hear about Eyewitness Unreliability

There is a pretty big problem with alerting a jury about how unreliable eyewitness testimony is: the expense of hiring an expert witness. A defendant could agree with everything a prosecutor asserts except the identity of the perpetrator, but the defendant is going to need someone to testify about eyewitness unreliability.

Anything a lawyer says during opening or closing arguments needs to be supported at some point during the trial; a lawyer cannot just assert during closing arguments that eyewitnesses are extremely unreliable. To allow the jury to hear that information, a lawyer needs a witness, and it has to be an “expert witness.” The Utah Rules of Evidence, which are based on the federal rules, say that any witness testifying on scientific or specialized knowledge, and not on “the witnesses’s perception” (what they personally saw or heard), must be certified as an expert.

Expert witnesses are paid for their time, both in preparing for trial and they day of the trial. If they have to travel, it is normal to pay for travel expenses and food. How much an expert is paid depends a bit on their specialty. Rare specialties and specialties in which a person could be making a pretty good salary outside of court are paid more. Experts on eyewitness unreliability would fall into the “rare” category and are paid accordingly.

This has the compound effect of compromising their integrity in the minds of the jurors. When experts testify, they are routinely asked about the payment for testifying. Many are paid more than $100 an hour, and the jury may conclude the expert will say anything for that much money. Many lawyers decide it is not worth the price to tell the jury, especially if there are other arguments in favor of a not guilty verdict, and other defendants cannot afford the price regardless.

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It Didn’t Happen That Way

If there were a piece of scientific evidence that had a 30% failure rate, we would not let it into court. Polygraphs, which have been shown to be accurate between 90 and 95% of the time, are inadmissible. The justice system has decided that juries will give too much weight to the information. Yet eyewitness testimony, in study after study, has shown to have high error rates, but is not only let into court, it is frequently the determining factor in a jury’s decision.

The rules of evidence are quite complicated. The central rule is that the evidence has to be relevant. After that, most rules are designed to keep juries from letting the wrong factors determine their decision. In other words, the evidence is relevant, but due to human nature, a jury either will not hear it at all or a judge must carefully limit the evidence in order to prevent that particular piece of evidence from being the only thing a jury considers.

Studies have shown there is no correlation between how confident a witness is and how accurate their memory actually is. But a confident witnesses is a more believable witness, so prosecutors encourage witnesses to state a high degree of certainty to a jury.

Most people overestimate their own ability to remember things, and likewise overestimate other people’s memories. False memories tend to accord to our philosophy and world view. As a recent slate article put it, “The scary part is that your memories have already been altered. Much of what you recall about your life never happened, or it happened in a very different way. Sometimes our false memories have done terrible things. They have sent innocent people to jail.”


Science and Forensics, Part 1: Introduction

The criminal justice system has a problem. No one knows just how reliable some types of forensic evidence are. These forensic fields were developed by crime investigators instead of by scientists. Not only haven’t they been proven to be reliable, there’s a question of whether or not they’re based on science at all. Some of them are better classified as superstition, but the criminal justice system has been slow to weed them out.

Bad forensic evidence usually makes its way into Utah courtrooms through expert testimony. Someone can testify about their credentials—frequently from spurious colleges or organizations—and then the court certifies them as an expert in a particular field. Under the Utah Rules of Evidence, judges are supposed to prevent experts from testifying about junk science. Utah Rule 702 governs expert testimony, and judges are required to make sure that the specialized knowledge that the expert purports to have is “reliable,” “based upon sufficient facts or data,” and has been “reliably applied to the facts.” Most judges do not have the expertise necessary, however, to determine if an expert’s testimony actually meets that criteria.

In a previous post, I argued that juries demanding that forensic evidence accompany eyewitness testimony has been a positive trend for criminal justice. I still believe that, but it’s also important that hard science support all forensic testimony.

The best forensics were developed independently from crime investigation and have other applications. DNA evidence is the gold standard for good forensic evidence. Everyone has DNA, it’s unique (even identical twins have a little variation), it’s quantifiable, and DNA tests can be replicated from one lab to another. Through CODIS (the Combined DNA Index System), the FBI keeps a large database of individuals’ DNA to help identify suspects in certain crimes. The one drawback is, unlike on television where it takes just a few minutes, it actually takes weeks to get the results.

Some forensic fields lack applications beyond crime investigation and don’t have independent verification. Those fields need to be subjected to the scientific process. That includes independent experimentation, peer review, and the ability to replicate conclusions. Most people are surprised when they learn that much of the forensic evidence that we were led to believe is scientific, has actually never been subjected to the scientific process, and no one has proved that they are reliable. In such fields, two different experts can come to completely different conclusions or their conclusions can be influenced by what they know about the crime they are investigating.