Friday, July 25, 2008

Eyewitnesses and the 'feeling of knowing'

I'm increasingly convinced that recent advancements in neuroscience will, in a very few years, begin to revolutionize several fundamental sets of assumptions on which the criminal justice system is presently based - most immediately regarding eyewitness identification and the reliability generally of witness testimony.

In Dr. Ginger Campbell's Brain Science Podcast #42, she reviews a book by Dr. Robert Burton - On Being Certain: Believing you are right even when you are not - focusing on a question that comes up frequently in cases resulting in DNA exonerations involving erroneous eyewitness identifications: How is it that witnesses can believe to their core they are testifying accurately but identify alleged perpetrators who absolutely didn't do it?

How can one be certain, in other words, and at the same time utterly and profoundly wrong?

According to Dr. Burton, "certainty" is really the equivalent of an emotion - it's a feeling, not a conclusion, that has "involuntary neurological roots." We don't know what makes us feel certain because in a literal sense by the time we do, the information no longer exists. When our synapses fire, they release and extinguish all the information about why they fired in the first place - the conscious mind, OTOH, merely notes whether they did or they didn't. Those subterranean "hidden" impulses underlying our thoughts and behavior constitute what psychologists consider the subconscious or unconscious mind.

There is no physiological distinction between the processes in our brain that generate conscious or unconscious thought, says Burton. That distinction has a philosophical but not necessarily a biological basis; for the mind, conscious and unconscious thought are an intermingled process that simultaneously includes both types of brain activity. According to this view, the "feeling of knowing," i.e., certainty, is an unconscious impulse that attaches itself onto conscious ideas and makes us believe them.

From the research Burton cites, you get the sense that people's certainty in their beliefs routinely outdistance the accuracy of their memory, a notion which has important implications when evaluating eyewitness testimony. Burton detailed the results of a study performed following the Challenger space shuttle disaster, where an academic interviewed 106 students the day after the tragedy then again 2.5 years after the event about their memories of where they were, who told them, how they reacted, etc. Half the respondents made errors compared to their original recollection, and a quarter of the accounts were significantly different than students originally remembered. Fewer than 10% remembered all the details the same. Many students whose stories had changed, however, maintained a high degree of confidence in their later, false recollections ... even after being shown their original answers in their own handwriting.

This "feeling of knowing" is "not under conscious control." Citing the example of a baseball player who physically must begin to swing before the pitcher releases the ball but says later he reacted to the trajectory, Campbell says, "Our brain makes us think that it knows things that it can't really know." (Many optical illusions similarly rely on the brain's ability to force itself into such moments of cognitive dissonance, thinking it knows things that cannot be.)

Burton calls this sense of being right "thought's original yes-man." But what is the genetic benefit of a feeling of knowing that's sometimes actually false? Burton says the feeling stems from the brain's pleasure-reward system in the upper brain stem, using dopamine as its key neurotransmitter. The pleasure-reward mechanism activated by certainty, he says, connects to parts of the brain that manage both emotion and cognition.

This sense of certainty could be an evolutionary adaptation to confronting abstract choices that have no clear cut answers in the face of perilous threats, says Campbell. Without this internal reward system endorsing the correctness of our actions, we could be paralyzed by fears and uncertainty in the face of immediate danger. All the talk of evolutionary adaptations, she and Burton emphasize, are speculative explanations, but it's a reasonable hypothesis for why our biological reward system might be hardwired that way.

The brain dynamics involved with certainty are essentially similar to patterns of addiction, said Burton, with the brain getting satisfying rewards in the form of a dopamine boost that reinforce certainty just like addicts get a dopamine jolt from drugs through the same expectation-reward mechanism.

In other words, Drs. Campbell and Burton think people can be addicted to their own beliefs in the same way an addict might be hooked on heroin or meth. Burton wonders if humans may have an "addiction to the pleasure of the feeling of knowing." Burton thinks neuroscience should "let go of the myth of the autonomous, rational mind" able to overcome its own subconscious prejudices, insisting that "The feeling that a decision is right is not the same thing as providing evidence that it is right." Indeed, when the beliefs in question are memories, as evidenced by the Challenger experiment, they may be simultaneously quite mutable and firmly believed.

The feeling of knowing cannot be dismissed, says Campbell, just because it occurs in parts of the brain where its functions are obscured. However, Burton's findings dictate that a feeling of certainty should not be considered a substitute for corroboration. "In real life we constantly make decisions with incomplete information," she says in conclusion, "but we also seem to have a tendency to feel certain about these choices."

What are the implications of these findings for the raft of DNA exonerations that followed erroneous eyewitness identifications? For starters, perhaps juries would be less swayed by a witness testifying with "certainty" if it were widely understood that that's really an emotion instead of a conclusion? What's more, when a person feels "certain" they're more likely to overlook alternative explanations and less likely to question their own assumptions.

I'm sure there are many other implications for this research in the criminal justice arena - what else comes to mind?

Dr. Campbell's podcast was a bit on the long side (about an hour) but well worth listening to in its entirety. She does a great job of breaking the subject down for the non-expert listener, and Burton's book sounds interesting as well. I can't help but believe some of these ideas will percolate up from the hard sciences into the law and the courts before too very long.

5 comments:

bob42 said...

Information about the (un)certainty of eyewitness identification should be explained to jurors in the future.

For the present, there's some DAs, Judges, and others that could use a bit of education too. In many of the couple hundred recent DNA exonerations, "the system" had denied requests for post-conviction DNA testing on the basis of eyewitness testimony.

These days, they're getting it right in Dallas. But Dallas now has the benefit of a DA that's more interested in justice than his conviction stats.

"DNA testing could have freed Patrick Leondos Waller seven years ago from a life sentence for armed robbery and kept the real criminal in prison.

But because former Dallas County District Attorney Bill Hill objected, Mr. Waller's efforts to obtain genetic testing were delayed until last fall. That was long enough for the man science has now identified as the perpetrator to elude justice for the crime that also included a rape and kidnapping.

DNA tests have now cleared Mr. Waller. The district attorney's office said two men who recently confessed to the 1992 crime cannot be prosecuted because the statute of limitations has expired. One of the men, whom DNA evidence definitively links to the crime, was paroled in February after serving 15 years for burglary."


(more...)

We'd be better off with a lot fewer "tough on crime" career politicians as DAs, and more of the "fairness counts" attitude exhibited by Dallas County District Attorney Craig Watkins.

bob42 said...

btw, I was pleased to see Grits in the link column at the Texas Innocence Project.

Anonymous said...

How can one be certain [...] and at the same time utterly and profoundly wrong?

Followers of different religions have been wondering this about each other for centuries.

ryanpaige said...

I had a weird example of this sort of thing in my own life just a couple of months ago.

I was watching a television show with my wife about unusual places. One of the places was the Winchester Mystery House in San Jose, CA. I mentioned to my wife that, when I was a kid, I visited the house with my mother and great aunt. I described to my wife several things I remembered from the visit.

A couple of days later, I mentioned to my mother that I saw the house on television and mentioned our trip. My mother informed me that we never went to the Winchester Mystery House. We had talked about going prior to our trip to California, and my mother had told me some things about it, but once we were on the trip, we ended up going somewhere else.

I was absolutely certain we had toured that house on my trip when I was a kid. I would've sworn up and down with as much conviction as possible that I had been there.

Of course, now that I write this, I get the feeling that I've posted this on this blog before, but I'm much less certain of that.

Anonymous said...

Here's a big implication you missed - jurors feeling certain about a verdict in the face of evidence that implies but does not prove guilt. The certainty emotion is probably what allows jurors (and prosecutors) to sleep at night after sending someone to prison for 40 years based on a guess.