Why eyewitnesses fail | Thomas Albright | TEDxSanDiego

I don't know about you guys but I fly a lot mostly for work at the end of many of my flights I confront this problem problem surely many of you are familiar with this I know what my bag looks like at least I think I do but the airport's remind us that many bags look alike indeed they do most are black most are about the same size and shape if you have any distinguishing characteristics which is kind of weird and of course they're way too many of them on the luggage carousel and so we make mistakes I can't tell you how many times I've lifted somebody else's bag off the carousel only to realize that it wasn't mine twice I watched in dismay if somebody grabbed my bag and disappeared into the crowd and LaGuardia woman once got as far as a taxi line out front before I caught up with her all which can be pretty distressing especially when you're traveling but in the end it's really just a minor inconvenience just a little bit of rushing around or perhaps waiting for somebody to realize they picked up the wrong bag trivial in the grand scheme of things but now I want you to consider a similar type of misidentification problem but one with severe tragic consequences in 2004 a 16 year old high school student from Lemon Grove California known as Erica was abducted by a man while walking to a friend's house Erica was tossed into the roadside bushes just the other side of this tunnel formed by the highway 94 overpass and she was sexually assaulted Erica punched her assailant repeatedly in the face eventually broke free and was rescued by a passerby now there were two significant witnesses to this crime Erica of course and a man by the name of angel Rivera who happened to be driving by both witnesses described the assailant as white about 5 foot 10 medium build brown hair and a goatee Eric actually provided a drawing and the in the sheriff's notebook she can get a sense of what he looks like there Erica also reported that she'd seen the assailant driving a pickup truck and she put it it was a crappy looking pickup truck and and there's a drawing of the pickup truck so you know what it looks like based on these limited Clues the San Diego Sheriff's Office eventually detained a 25 year old construction worker from San Diego by the name of Uriah Courtney that's Courtney on the right and you can see it does bear certain resemblance to the drawing Courtney was presented to both of the witnesses and a lineup lineup seized days typically take the form of a set of photographs usually six it's called the six pack so there's a six pack for the for Courtney Courtney's the person and the the lower-left both witnesses picked Courtney out of the lineup and in the end the prosecution's case rested entirely on this eyewitness testimony not a shred of physical evidence came to light and in 2006 uriah Courtney was found guilty by a San Diego jury and sentenced to life in prison when he was permitted to address the court Courtney maintained that he could not express remorse for a crime he did not commit to his accuser he simply said I am sorry Erica but you were mistaken in your identification of me it was a simple mistake but one with monumental repercussions because now neither of us is receiving the justice we deserve in 2010 the Innocence Project took up Courtney's case while DNA from the original investigation had proved inconclusive a later analysis found DNA on the victims clothing that was incompatible with Courtney and instead matched a former convict living in Lemon Grove not far from the crime scene based on this new evidence Courtney's conviction was vacated and in 2013 he was released from prison after having served 8 years behind bars sadly this okay this is not unusual the Innocence Project is recorded nearly 350 such dna-based exonerations in about three-quarters of these cases eyewitness identification or more properly eye witness misidentification with significant evidence leading to conviction so we should rejoice in your i Courtney's freedom and that of these many other people who suffered a similar miscarriage of justice but it's a civil society and one with a scientific reckoning we also have to ask what the hell happened here why do I witnesses identify the wrong people and 2013 the National Academy of Sciences addressed this question by convening a study group to look at the validity of eyewitness testimony this committee which I chaired together with Judge Jed Rakoff of the New York federal district court developed a number of recommendations which are already beginning to reform the use of eyewitness evidence this report is freely available online today I simply want to go to the heart of the matter and tell you why I witnesses fail the ability to recognize objects depends upon objects we've seen before depends upon accurate vision and memory it's one of the most fundamental and highly valued of human skills we take this ability for granted and we apply it in pretty much every possible context I can find my car in the parking lot every day so can you I can locate the book I was reading on the shelf in the library and I can identify my dog and the big pack of dogs at dog Beach moreover because we tend to believe our own version of what we've seen we naturally grant the same confidence in others it must be true because she saw it with their own two eyes but of course we make mistakes and I don't mean to sound glib but I hope that you see that there's a similarity between the Araya Courtney's problem and my misappropriated luggage the consequences are vastly different I just chased down a sheepish traveler Uriah Courtney went to prison but the root causes the same in both of these cases identifications were made based on the visual experience and memory of human observers and in both cases those decisions were wrong now it turns out that the brain systems that underlie visual perception and memory have been the subject of a lot of research over the past few decades and from this science we know that there are three factors that affect the usefulness of reported experience uncertainty bias and confidence uncertainty refers here to the fact that vision in general is far from perfect the reason is visual noise vision is plagued by noise for many natural sources including such things as for optics of the eye dim illumination or distracting features in the visual scene in the presence of noise were faced with a lot of uncertainty about what we're actually looking at such that any decision we might make has a significant likelihood of being wrong so if uncertainty can be likened to a breakdown of accurate sensory communication biases the patch the holes things together it's the patch that helps us fill in the blanks in the presence of visual noise and uncertainty fill in the blanks with what we believe is likely to be out there based on our prior experiences with the world confronted with a noisy visual world as we typically are our memory based expectations are biases grants us the perceptual certainty that we need to survive but here's the catch the same system that grants perceptual certainty in the face of noise is also capable of introducing content that has no bearing on external reality or to put it differently our misinformed biases caused us to perceive things that don't exist to make matters worse oftentimes we're absolutely confident about it this is of course exactly what magicians aim for they create conditions of uncertainty they introduce bias and they leave leave us with a strong sense of confidence about something that didn't actually happen but if the goal is truth as it is in the criminal system then misinformed biases and overconfidence are the hidden enemies now I can give you a sense of this interplay between uncertainty bias and confidence using a simple example the next slide I'm going to show you a stimulus a very noisy visual pattern and I want you to raise your hand if you see something meaningful don't shout it out because of course you give it away to everybody else in the room just raise your hand alright so there you go I can't really see anybody I have a couple hands coming up you people think you see something the rest of you are pretty much clueless because it is a free noisy pad and now now I'm going to introduce a bias I'm gonna give you a little piece of information you didn't have before there you go you see a face of a man looks a little bit like Che Guevara we'll call him che everybody see che all right so now we're gonna go back to the original noisy image and again I want you to raise your hand if you see something meaningful all right it's a lot of a lot of hands coming up hands coming up for people who didn't raise their hands before I still see a few people who are not raising their hands there might be something wrong with you people so we're done we're done today you come back the lab will take a closer look but but for those of you who are raising your hands I want to point out this is the same image I showed you a moment ago the image hasn't changed you changed I fed you a bias which is now dictating your perceptual experience of what is undeniably a very noisy visual stimulus and here's the worst part you see che now and you'll always see che I didn't ask your permission but I've modified your brains forever you-you-you can't go back I might tell you well that's not really ke it's a it's a pile of dirty laundry or it's a Dalmatian in a snowstorm or it's maybe it's a map at the Aegean islands but I guarantee you you're gonna stick with che because you're now supremely confident about say okay makes sense to you now of course a lot of reasons for your confidence let the least of which is the fact that everybody else in the room also sees che all right so it's this unholy trinity of uncertainty bias and confidence it's the primary reason why I witnesses fail so bear that in mind let's take a moment go back and look at the conditions in Lemon Grove there are a number of features of the viewing conditions there that could have introduced noise and uncertainty on the part of the eyewitnesses things such as emotional distress or perhaps the brief duration of events a particularly prominent factor is poor illumination since the events occurred near the entrance to this tunnel under the highway 94 overpass the witness angel Rivera may well have seen a white man with brown hair and a goatee but he saw him in a dark tunnel which means that there's necessarily some uncertainty in his experience there also factors in this case that could have introduced bias on the part of the eyewitnesses it's well known for example that the the ability of people to discriminate faces of their own race is far better than the ability to discriminate between faces have erased different from their own it turns out in this case the witness angel Rivera was Hispanic the culprit was white which means the own race bias is very likely to have been in play under those circumstances and could easily have affected the outcome another factor in this case that could have introduced bias is the fact that the cop who administered the lineup knew which person in the lineup was the was the suspect that is he wasn't blinded to the status of the suspect which opens the door for the possibility of unintentional unconscious unwitting communication in the form of subtle signals like I Reutimann's her body posture they could have been picked up on by the eyewitnesses and bias the outcome finally we have confidence or more properly overconfidence there's probably the most pernicious reason why I witnesses failed a witness baby wrong because of uncertainty and bias but if the witness testifies in court with confidence it's very difficult for a jury to discount their version of events and the big problem here is that witnesses become more confident with the passage of time they repeatedly tell their stories to others who appear to believe them which promotes a cycle of confidence inflation such that by the time the witness gets to court they're absolutely certain they wouldn't be there if they weren't when Erika was asked about her confidence and her identification of Uriah Courtney she replied I will never forget what he looks like when angel Rivera was asked whether he had any doubts about his identification of Uriah Courtney he replied not at all so in the end you're right Courtney spent eight years of his life in prison not because these witnesses were deceitful or malicious but because the prosecutors and the deciders of fact and pretty much everyone else involved in this case failed to appreciate how a toxic combination of uncertainty bias and overconfidence can cause decent intelligent well-meaning people to say things that are untrue and identify things they've never seen before the science of vision and memory is very clear on this point so what are we to do the recommendations of the National Academy of Sciences report are already beginning to have a positive effect but more generally as a society we need to come to terms with the fact that there are insurmountable limits to visual perception and memory that are imposed by our biological nature and the properties of the world that we inhabit it is this baseless fabric of our vision to paraphrase Shakespeare than done with and does so far more often than we're aware or that we're willing to admit as the old saying goes seeing is believing but neither seeing nor believing equivalent to truth thank you

Channel: TEDx Talks

Views: 29,179

Rating: 4.8188152 out of 5

Keywords: TEDxTalks, English, United States, Science (hard), Cognitive science, Criminal justice, Memory, Neuroscience, Prison

Id: l05NGp_z6TI

Length: 15min 31sec (931 seconds)

Published: Tue Nov 15 2016