Debating the Evidence

I’ve posted two articles on the “CSI effect.”

The first is a 2004 article from USA Today that claims TV shows like CSI have impacted U.S. courtrooms. The lawyers interviewed believe that programs like CSI give jurors the sense that forensic evidence is necessary and infallible. The article claims that exposure to these shows is affecting the way lawyers prepare cases and quotes prosecutors who feel it is more difficult to win convictions when scientific evidence is lacking. The author describes a case in Galveston, Texas in which the defense hired an expert to help pick jurors who were familiar with shows like CSI and Law and Order. The prosecution never recovered the head of a dismembered millionaire, and the defense claimed that wounds to the missing head may have supported their theory of a self-defense murder. The defense attorneys had hoped that jurors who viewed CSI would recognize “a gap in the evidence” and acquit. They did.

Here are some more examples of the CSI effect the author cites:

• In Phoenix last month, jurors in a murder trial noticed that a bloody coat introduced as evidence had not been tested for DNA. They alerted the judge. The tests hadn't been needed because the defendant had acknowledged being at the murder scene. The judge decided that TV had taught jurors about DNA tests, but not enough about when to use them.

• Three years ago in Richmond, Va., jurors in a murder trial asked the judge whether a cigarette butt found during the investigation could be tested for links to the defendant. Defense attorneys had ordered DNA tests but had not yet introduced them into evidence. The jury's hunch was correct — the tests exonerated the defendant, and the jury acquitted him.

• In Arizona, Illinois and California, prosecutors now use "negative evidence witnesses" to try to assure jurors that it is not unusual for real crime-scene investigators to fail to find DNA, fingerprints and other evidence at crime scenes.

• In Massachusetts, prosecutors have begun to ask judges for permission to question prospective jurors about their TV-watching habits. Several states already allow that.

• Last year in Wilmington, Del., federal researchers studying how juries evaluate scientific evidence staged dozens of simulated trials. At one point, a juror struggling with especially complicated DNA evidence lamented that such problems never come up "on CSI."


The second article is a more recent report (2008) that I found on the Arizona State University research magazine website. The author describes a study in which researchers “presented a mock trial to 48 jury-eligible university students.” The main evidence was a recovered hair follicle that scientists had linked to the defendant. The researchers concluded that participants who watched CSI (or similar shows) were not more or less likely to convict. So far, similar studies have not shown that CSI hasn’t affected the likelihood of an acquittal. One of the researchers involved in the survey of university does believe that CSI has impacted the mindset of jurors. He believes that the program has made more people aware of forensics and may even make people more skeptical of scientific evidence.