CSI Effect

[Barnaby]

The press is partialy attributing the Casey Anthony acquital to the "CSI Effect." To those not familiar: Casey Anthony most probably murdered her 2-yr-old daughter, Caylee, and then did not report her daughter missing for a month, spending her time instead partying at "hot body contests". Caylee's skeletal remains were eventually discovered months later. There was powerful circumstantial evidence suggesting Casey was a premeditated killer, yet the jury acquitted her in short order. It is speculated that cultural variables, specifically exposure to television shows like Crime Scene Investigation (CSI) - in which seemingly irrefutable scientific evidence (e.g., DNA) links killer with victim - contributed to the acquital because such evidence was notably missing in this case.

I am all in favor of increasing scientific and technological literacy in the public. But to what extent does DNA evidence (or lack thereof) devalue other types of cirumstantial evidence, such as behavioral analysis and good old common sense? And related to Jack the Ripper, what hope do we have of identifying a killer when the public seemingly demands bullet-proof forensic evidence?

[lynn cates]

Csi

Hello Barnaby. Excellent observation. I noticed that, after listening to a few minutes of that too silly programme to which you refer, that a good deal of their vocabulary approximates a good deal of what I read in various posts on Casebook--now I know where those ideas come from.

Here's a conundrum regarding DNA. It is said that no 2 people can have precisely the same DNA. But how does one know that? Well, perhaps because, so far, such a match remains undiscovered.

For decades it was claimed that no 2 snowflakes were exactly alike. But, recently, this was shown to be false.

So my question is this, What happens if 2 samples of DNA turn up, from different individuals, and yet they are molecule for molecule the same?

Oh, what backpedaling some of my colleagues in the science department (not to mention statistics people in the math department) will do when that time comes.

Cheers.
LC

[Errata]

I am all in favor of increasing scientific and technological literacy in the public. But to what extent does DNA evidence (or lack thereof) devalue other types of cirumstantial evidence, such as behavioral analysis and good old common sense? And related to Jack the Ripper, what hope do we have of identifying a killer when the public seemingly demands bullet-proof forensic evidence?

This is actually just a twist on an old phenomenon. It is most commonly seen when prosecuting someone for murder when the body was never found. And that rarely ends in conviction. It has to do with overblown notions of "reasonable doubt" more than anything else. Often people think that if another scenario is even possible, then that constitutes reasonable doubt. The real litmus test is if another scenario is likely. Maybe not AS likely as the prosecutions case, but likely enough.

[Robert]

From the little I've seen of these shows, someone hits a computer keyboard, up pop some pictures and impressive-looking charts, and they shake hands on it. Case closed. It's a wonder they get an hour out of it.

[TomTomKent]

Unfortunately the CSI effect is well known. There are some lawyers who have based their defense argument on the case of the evidence there is not, rather than disputing the evidence there is. So a lack of DNA is a good example, people assume it is something that SHOULD be found at a crime scene, rather than something that MAY be found, if you are lucky.

The same effect can be applied to computers, CCTV, and other "miracles", and is no doubt a factor of Percieved Wisdom. By the same token we could assume it would be easy to recognise child molesters as they are the funny looking dirty old men, or we should be swimming in evidence for the idea that people thought the world was flat before Columbus. Or as simple as the "If the guy in the dock didn't do it, you need who know who did" fallacy. The law itself is often misunderstood because of cliches in fiction. People are far more likely to see a TV show about cops than study law or the process of detection, so they assume that something that happens in every tv show must be believable.

[lynn cates]

right

Hello Robert. I'll say.

It's all rot, and Inspector Clouseau is their better.

Cheers.
LC

[Robert]

Lynn, they won't get anywhere until their computers recognize "writ of fealous jage" as a motive.