Tuesday, December 15, 2009

Eyewitnesses miss big changes in their environment, like the person in front of them

An alert reader points to this remarkable video of an experiment regarding "change blindness" to judge how observant (or not) average people are in casual settings, via Boing Boing:

If 75% of people in the experiment don't notice they're all of a sudden speaking with a different person, how likely do you think most eyewitnesses would be to identify the correct person later in a police lineup or photo array?

More and more, studies like this have convinced me that eyewitness testimony should always require corroboration unless it can be established that the witness knew the defendant before the offense.

See related Grits posts:


Anonymous said...

One of my all-time favorite tests about perception:



Anonymous said...

Some liberals want us to believe that anyone who would identify a criminal has to be discredited. Like a defense attorney, Grits is a non-stop advocate trying to protect his pets by making us believe that you can never be sure if anyone is guilthy so his pets must all be turned loose.

He advocates with a blizzard of one sided stories trying to constantly create doubt so his pets can slip free. According to his spin, since we can never be sure about anything then they all must be turned loose.

Anonymous said...

to Anon 7:54-

Eyewitnesses identify suspects, not criminals.

And the word was "corroboration", not "discredit".

to Anon 12.25 -

Try this one on for size...

TheEvilOne said...

Dead on.

I believe that it takes multiple encounters with a particular face to develop the ability to recognize it. When one meets someone one already knows even in a strange situation there is an almost audible click in one's mind at recognition.

But if one witnesses someone one does not already know commit a crime, the most one can say at a line up or photo line up is "that one appears closest in appearance to my memory" or "he could have been the man I saw".

I once witnessed a bag snatch and pursued the man until he jumped in a car and drove off and I attempted to drag the keys out of his ignition. Later at the police station I looked through photo books, but I do not believe that were the man's picture in these books I would have recognized him.

Gritsforbreakfast said...

7:54, the commenter at 9:57 has it exactly right. "Corroborate" is not remotely the same as "discredit."

I'm always amazed at folks from the "tuff-on-crime" crowd who think it's better to convict SOMEONE, even if it's the wrong person. That of course leaves the real perp on the loose, as happened in dozens of DNA exoneration cases around the state, but I guess not wanting to incarcerate an innocent person instead of the real criminal is apparently now a "liberal" view. Very bizarre how these terms evolve.

Anonymous said...

When we consider any one of Grits arguments individually it might make sense. You probably have noticed that he argues against conviction in a hundred different ways - from a hundred different angles. Am I wrong about that?

There is no evidence that he wants to "incarcerate ...the real criminal" as he says. Like the OJ defense team, he uses anything he can find to build his one-sided case. Can anyone doubt that his hundred arguments all seem to be on one side of the fence? Being so steeped in his ideology, that's the only side he thinks exists.

There is no evidence that his critics want to "incarcerate an innocent person instead of the real criminal" as he claims. Being so sure of the righteousness of his position, he is quick to build up straw men to attact to try to prove his point.

Gritsforbreakfast said...

12:36 all the big police and sheriff's departments, DPS, the AG, TDCJ, TYC, the police unions, many DAs, and a zillion other entities all have paid PR staff who do nothing but churn out positive spin for what they do. On top of that, there's all the tuff-on-crime pols who want to get their name in the newspaper. Their side already gets told. The goal of this site is to fill in the gaps caused by usually lazy media who rely nearly exclusively on those sources and fail to look deeper at real problems in the justice system. So your point is valid, but there's a reason for it and in the big picture I'm just balancing out the official spin, or at least some of it, with a differing perspective.

As for your statement: "There is no evidence that his critics want to 'incarcerate an innocent person instead of the real criminal' as he claims"

You may not "want to," but you certainly don't feel a need to take steps to prevent it. (Or at least, you haven't said so.)

IMO if you know the details of research about fallibility of eyewitness ID and then oppose requiring corroboration or reforming lineup processes in ways that reduce error, there's no way to interpret that except that you don't really care if an innocent person is prosecuted. Actions speak louder than words. Maybe you don't actively WANT that to happen, but preventing it is not a priority for you. Otherwise, you'd have more to offer than knee-jerk reactions pretending any criticism of law enforcement is liberal and dismissing it without debate or thought.

Anonymous said...

"You may not "want to," but you certainly don't feel a need to take steps to prevent it."

The phrase you're looking for, Grits, is "deliberate indifference."

Anonymous said...

Folks, the big-ass red letters at the top of each and every Post here on GFB is the title and the topic. Grits is allowing us to discuss (IT) publicly and those that hijack (BLOGJACK) the forum simply pisses off everyone.

Why in the hell he allows one to do so without any links back to the commentator(s) is beyond me. But count yourselves lucky, for I look forward to the day that we can associate a name with a hijacker.

Hey Grits, had to get that out, sorry. I know you do what you do for your own reasons. I spewed this as an anonymous on purpose. I just hate to see your posts get (BLOGJACKED) (if that's even a word?) attempted that is. Thanks

Anonymous said...

You are kidding me. You are referring to this experiment as evidence that people are unreliable witnesses. i am not making an argument either way but show me how the mindless process of registering for a psychology research experiment has any external validity regarding the ability to remember information in situations which there is emotional engagement, fear, or any meaningful life interaction going on.

Our minds are powerful negotiators of our environment. If we were to process all information that we encounter we would all be psychotic or catatonic. We select situations in which we process information. Put someone in a situation where something startling or meaningful seems to happen and I bet memory recall is much much better. I am disappointed Grits. I thought better of your ability to apply such information to reality.