Monday, September 14, 2009

The folly of forensics: lessons from my egg roll.

If you made it all the way through my very long Skeptic article on the criminal-justice system, you know that eyewitness identificationsonce viewed as the gold standard of guilt in criminal cases, especially rapesare now being revealed as the shaky evidentiary tool that law-enforcement officials always privately knew them to be. In fully 75% of the DNA-based exonerations wrought by the Innocence Project, there had been a positive ID at trial.

Tonight I got a lesson from my egg roll in why so-called "forensics science" should probably be the next to go out the window.


Some background. Sunday night after dinner I swept and vacuumed, and this morning my wife and I were both out of the house early without eating breakfast. In other words, nothing took place on the kitchen table all day until dinner. I was the first to arrive home, and in fact, when I walked into the house at about 4:
30, with the sun streaming through the blinds and across the hardwood floors of the dining room and kitchen, I remember being pleased at how sleek and spotless the rooms looked; like a nice photo from one of those "modern home" magazines. Anyway, my wife arrived moments later with Chinese food. As I set out plates, she placed the bag containing the food on one end of the long dining-room table, the end where we always sit. All of the food was removed on that side of the table, a good six feet from the table's other end, where no one sat. Since she'd also brought glasses and drinks to the table after setting the food down, and I'd brought napkins, neither of us found it necessary to get up for anything from the moment the bag was opened until the moment the meal was finished. What's more, the air conditioning was on, which means the windows were closed, which means there were no breezes to deal with.

And yet when I got up to put the plates in the sink a half-hour later, the first thing I noticed was a spray of crumbs at the far end of the table, beneath a chair upon which no one had sat. I went over to check it out. They were tiny pieces of an egg roll.

My point? How many episodes of 48 Hours or Dateline have you watched where a defendant was convicted based on testimony that sought to reconstruct the crime scene and thereby explain why the crime could've only happened a certain way? (That is, when a defendant isn't convicted because jurors "didn't like his demeanor at trial" or similar peripheral nonsense.) How many times have you heard "expert" testimony explaining why blood found in a certain place, or in a certain pattern, had to mean such-and-such?

My kitchen was not a crime scene tonight, thankfully. And yet I can guarantee you that a forensics expert who came to the house to "reconstruct" our dinner would've stated with certainty that someone ate at the far end of the table. "Otherwise," he or she might pose, rhetorically and with a knowing smirk, "how did those crumbs get there? Did they just walk across the floor to the place where they came to rest?"

Things happen all the time that no one can explain. You are positive, absolutely positive, that you left your keys on the counter...but you find them under the sofa cushion. There is no reason for them to be under the sofa cushion; you weren't even on the sofa! But there they are. You shrug off those puzzling episodes because they're inconsequential in the larger scheme of things. Then one day you're arrested for something and suddenly cops and criminologists are finding all sorts of ominous, incriminating significance in life's inexplicable little mysteries.

I find it frightening.

11 comments:

LizaJane said...

Oh, Steve. Just because you don't know the details of forensic science doesn't make it a non-science, or the bulk of the evidence discovered through its methods unreliable. Sure, there are probably faulty practitioners out there (poorly trained, unethical, dim-witted, whatever) as with any other pursuit in the world. But that doesn't negate the validity of any properly executed investigation.

The crumbs could have got there any number of ways. I imagined some bits of someone else's order (or your own, as it was being packed) falling onto the bag before it was folded over for transport. When you opened the bag to get your food out (focusing on the meal, not the packaging), it could have strewn those crumbs across the table and onto the floor. Just one scenario.

The keys are under the cushion because, although you clearly "remember" putting them in the proper spot, you didn't. You just think you did because that's what you do every single day, so it's sort of an "automatic memory." But this time, you didn't. Instead, you sat down on the sofa and the keys fell off/out and got worked under the cushion as you squirmed around (or if it's my sofa, your toddler HID them under the cushion, along with the remote, several socks, and one shoe).

Eye-witness reports are very different. They are completely unreliable. I had to ID someone in a (photo) line-up, and it was nearly impossible. I thought it would be easy, but I couldn't do it. But remembering something you saw is very different than using the laws of physics and the tools of science to determine things like velocity, how long something's been dead or in a certain place, etc. Very different.

Dimension Skipper said...

On the subject of faulty eyewitness accounts and then later being cleared by DNA evidence, I happened to catch today's (9/14/09) Voices In The Family with Dr. Dan Gottlieb on WHYY FM...

When 22 year old Jennifer Thompson-Cannino identified the man who had attacked and raped her as Ronald Cotton, she felt justice had been served. That was in 1984. Eleven years later, a DNA test proved Cotton had been wrongfully convicted, and Thompson-Cannino had identified the wrong man. Jennifer lived with extraordinary guilt and remorse, but found the courage to meet Ronald—only to discover that he had forgiven her long ago. Over the years, the two have become close friends and have devoted much of their lives to ensuring justice for the wrongfully accused. Together, they have written Picking Cotton which talks about injustice, hope and forgiveness."

For the duration of September '09 folks can listen to the podcast (mp3) of the program at that page I linked to, but I must note that it's an hour-long program. Probably the first 10-15 minutes or so would be enough to give you the gist, but I'm not really sure now. I thought the whole thing was of some interest myself.

It just seemed very pertinent to the topic and presents the victim and the falsely accused in a fairly unique light and more in-depth (especially psychologically, of course, since that's Dr. Gottlieb's line of work) than the typical reported news story might.
_______________

NOTE: Eventually, the program should be accessible on the September '09 Voices In The Family archive page, but apparently that page won't actually exist until October begins.

I am including the anticipated link here simply for the convenience of helping folks find the broadcast in months to come. I figure people could be stumbling/Googling across this page for years yet and the first link I provided above for use right now is simply always going to show a summary of the current month's broadcasts. I could link directly to the mp3 file itself, but I thought it more proper to direct folks to the Voices site first.

Steve Salerno said...

DS: Thanks, as usual, for providing a lot of useful context.

LJ: But in a way you make my point. Couldn't the Type-A blood have gotten there in any number of (improbable/unrecognized) ways, too? Even, say, the little drops of blood in OJ's SUV (or whatever it was)?

How do we know? How do we ever know?

Anonymous said...

Agree totally, Steve, in principle. The problem is, if you go by these standards you'd always have reasonable doubt and no one would ever be convicted of anything.

Rowan Manahan said...

Oh Steve ... It's ninjas. They're everywhere! Didn't you get the memo?

Steve Salerno said...

Rowan: Now, technically speaking, would ninjas have any rightful authority over Chinese food? That seems like it's crossing territorial lines or some such...

Rowan Manahan said...

As ever Steve, you make a good point. But here's the thing - someone moved the eggroll crumbs, you didn't see them, therefore ninjas. QED.

Steve Salerno said...

ipso facto.

LizaJane said...

Hiya Steve,

Yes, "Type A" blood is shared by millions of people. But it's not a "blood-type" match they test for in this sort of situation. They're not looking to see if the blood would be safe for transfusion. It's MUCH more rigorous (specific) testing, which greatly reduces (to near "0" if it's DNA testing) the chance of it being anyone but the person in question. All this, of course, assumes the person doing the lab work is doing it correctly. And I'd say that most of the time, it is.

Steve Salerno said...

LZJ: I'm not talking so much about DNA testing and the like. At least that's a science. I'm talking more about the kind of "evidence" that was compiled in the case of that author who was convicted of murdering his wife ("The Staircase Murders") or the Jeff MacDonald case, where forensics types "explained" how the crime occurred by looking at where blood was, and wasn't, found. And lots of other categories of so-called evidence that involves drawing inferences or devising patterns based on random observable facts.

And on an unrelated note, I've always said, if my freedom depended on my ability to explain where I was this past Friday at 7 p.m., or what I had for dinner that night, I'd be a goner. And my wife is a very good cook!

Dimension Skipper said...

Steve, I tried to look for a relevant post to place this under and there could be something more recent, but this was the best I could find quickly. Feel free to publish this as a comment or not, but mostly it's just a quick and easy way to toss this item in your direction.

Just thought you might be interested to take a quick glance at it since it fits right in with two of your fairly frequent topics, reliability of eyewitness accounts and issues of racial bias. I'm sure it's not anything you're not already aware of (in terms of the general topic), but just thought I'd toss it your way fwiw.

It's a blog item by Dr. John Grohol that popped up today in my PsychCentral feed, a site/feed I only recently discovered and added into my iGoogle feeds of interest:
______________

Are We Racially Color Blind Yet?

...

Pager et al. (2009) wanted to see if individuals of different races who had the same fictitious resumes would be treated equally when they applied for real, entry-level, low-wage positions throughout New York City. The researchers trained teams of participants — each of which included a white, black and Latino — to act and dress in a similar manner during the interview process. The participants were "chosen on the basis of their verbal skills, interactional styles (level of eye-contact, demeanor, and verbosity), and physical attractiveness."

Across the board, the whites of the teams were offered jobs more often than either blacks or Latinos. Many times the white candidates were also channeled to better positions than the one that the employer advertised. Blacks and Latinos, on the other hand, were only half as likely to be offered a job compared to whites. And when they were offered a job, it was often a lower-paying, inferior position than the position advertised.

And here’s the real kicker — employers chose a white applicant who was just released from prison just as often as they chose a black or Latino applicant with a clean background. In many employers’ minds, a white criminal is on equal footing with non-criminal blacks and Latinos. Amazing.

It’s interesting that the researchers studied whether criminality had any effect on a person’s perceptions of suitability for a job, because when it comes to race and crime, it gets even worse.

....


Of course, just click through to the linked item (which is short) for more if it's of any interest. It goes on to briefly discuss reliability of eyewitness accounts given the same cross-racial context and "own race bias" (ORB).