Summertime, and the living is easy.  Anne Read at Deliberations not only made the effort to pick out our summer reading, but read it for us and tells us what we need to know.  This can’t be said enough, if you don’t read every piece Anne writes, then you don’t deserve an acquittal.

Parsing Anne’s light summer reading (notably missing is Vanity Fair and GC, however), she brings us “Statistics in the Jury Box: How Jurors Respond to Mitochondial DNA Probabilities,” David H. Kaye , Valerie P. Hans , B. Michael Dann , Erin Farley and Stephanie Albertson, from the Journal of Empirical Legal Studies.  I know, next to Playboy, what kid didn’t drool over this.

I had long believed that the dangers of DNA evidence were overwhelming.  As defense counsel, how could we overcome the DNA expert who would tell the jury that our client was guilty with 99.99982% probability?  Sure, we would attack collection and contamination, but that percentage was so strong that it was all the jury would hear, right?  Wrong!

Although some jurors showed susceptibility to classic fallacies in interpreting conditional probabilities, the jurors as a whole were not overwhelmed by a 99.98% exclusion probability that the prosecution presented. Cognitive errors favoring the defense were more prevalent than ones favoring the prosecution.

That jurors were susceptible to “classic fallacies in interpreting conditional probabilities,” which of course is how the authors try to curry favor with me by acknowledging that the jurors, being clueless, just accept the conclusion by default, comes as no surprise.  Some jurors, the compliant, will invariably find the idea of thinking too taxing.  They will blindly accept whatever an “expert” tells them.  When there are two experts, either they shut down or their heads explode.  This can get very messy.

But on the other hand, there’s the good news.  “Cognitive errors” are more likely to favor the defense than the prosecution.  Hooray!  For those of you who view this as an unrewarding benefit, get over it.  Remember the old adage, if you can’t dazzle them with brilliance, baffle them with bullshit.  Take your good points where you find them.

It reminds me of my old partner, Howard Meyer, who won trials where he didn’t have a chance in the world.  I would watch him close, and listen to him spout some of the most ridiculous stuff I’d ever heard.  But I was wrong, not him.  He understood what jurors, people who didn’t live in the well of a criminal court, thought and, more importantly, didn’t think.  When he was confused, he knew they were confused.  He played on that confusion.  He used it to generate ever greater confusion.  And then he turned that confusion into doubt.  He exploited the limitations of a trial to educate jurors, and then exploited any misunderstanding.  It was really something marvelous to watch.

We often complain that jurors just don’t get it.  This, apparently, is true of DNA as well.  So rather than fear it, use it.  The prosecution’s witness will love to talk about the science of DNA, and given enough rope will either bore or confuse the jury.  That’s the hole you seek.  The peril of becoming too smart about DNA is to separate ourselves from our jurors, and lose our ability to appreciate how this science conflicts with everyday misunderstandings.  By the way, this is another “common sense” opportunity, to turn the prosecution’s appeal on its head and smack them with their own effort to fudge the evidence.

To learn more, read the entire journal article.  I plan to, just as soon as I finish GQ and Vanity Fair.