now that DNA has exonerated more than 230 men mostly in sex crimes and murder cases criminologists have been able to go back and study what went wrong in those investigations what they've honed in on is faulty eyewitness testimony over 75% of these innocent men were convicted in part because an eyewitness fingered the wrong person at the heart of the problem is the fragility of memory as one researcher told us we now know that memory is not like a videotape recorder you don't just record an event and play it back instead memory is malleable full of holes easily contaminated and susceptible to suggestion as in the case of Jennifer Thompson and Ronald cotton before this case did you think that there were a lot of innocent people put away no you didn't no I didn't innocent people aren't convicted of crime s they didn't commit I believed that what do you think now oh I know better I mean well over 200 cases nationally we've had a half dozen in this state alone the first of course was my case Hallelujah and as these innocent men have been freed in one state after the next we've learned something else that in all the cases where eyewitnesses were wrong the real perpetrator was not in the initial lineup when you're sitting in front of a photo lineup you just assume one of these guys is the suspect it's my job to find it and Jennifer did her job she found the suspect's photo problem is the suspect Ronald cotton was not the rapist Bobby P's photograph was not in the photo lineup right he was not in the physical lineup when the real perpetrator is not in the set is is none of them uh Witnesses have a very difficult time being able to recognize Gary Wells a professor of psychology at Iowa State University has been studying eyewitness memory for 30 years he says when the real guy isn't there Witnesses tend to pick the person who looks most like him I think that Ronald cotton and Bobby P look very much alike they have very similar lips shape of their eyes their eyebrows kind of go up in a look of surprise yes without him in the lineup Ronald cotton was the one who was in Jeopardy well says eyewitness testimony has two Key Properties one it's often unreliable and two it is highly persuasive to jurors I can see why it's so persuasive someone says I was there you'd believe that person you believe that person because they have no reason to lie yeah the legal system is set up to kind of sort between liars and Truth tellers and and it's actually pretty good at that but when someone is genuinely mistaken the legal system doesn't really know uh how to deal with that and we're talking about a genuine error here he walked us through what went wrong some of it counterintuitive when Jennifer spent 5 minutes studying the photographs she and detective gden thought she was being careful I didn't want to come across I don't think as somebody who's like that's the one I really wanted to be sure well says no good recognition memory is actually quite rapid so we find in our studies for example that if somebody's taking longer than 10 15 seconds it's quite likely that they're doing something other than just using uh reliable recognition memory so you're saying if she really recognized a guy it would have been almost instantaneous quite quick yes he says a better way would have been to show Jennifer lineup photos or people one at a time so that she would compare each one directly to her memory rather than to one another Well showed me a study in which more than 300 subjects were shown deliberately shaky videotape of a simulated crime you look out a window and you see some suspicious Behavior what happens is we tell them later then this person that you saw right there put a bomb down that uh down the air shaft there then subjects are shown a lineup and asked to identify the bomber that would be so hard I just saw it and of course you're particularly cautious right now you know now after we've talked probably not to pick anyone no no actually I know I actually know who it is because if I had come upon that I think it's this guy Am I Wrong mhm am I wrong yeah I'm wrong yeah okay so there you go and I'm already saying how hard it is it's none of them it's none of and it's so it it's so and you know about it bizarre you know about this we've talked about this so so this is the diffic this is what makes it so diff to me I'm mortified I feel like Jennifer well says in real life the mistake is often compounded by what happens next remember the seemingly innocent information Jennifer says she got from police after she picked Ronald cotton out of the physical lineup that's the same person you picked out in the photo lineup so in my mind I thought bingo I did it right well studied what that reinforcement does after half a subjects did what I did picked an innocent person from this lineup he told them nothing then asked them questions about what they had seen very few felt highly confident about their choice only about 4% are saying they had a great view which is good because we gave them a lousy view only about 3% are saying they make out details of the face that also is good because they they really couldn't but he told a second group of subjects after they made the same incorrect choices good you pick the suspect now what happens is 40 almost 45% of witnesses now report that they were positive or nearly positive notice that over 1/4th of them now say they had a great View and this is really what happened to Jennifer it is what happened with Jennifer what this seems to be saying is that a reinforcement Alters memory it does dramatically it does he says the solution is to have someone independent administer the lineup someone who doesn't even know who the suspect is and certainly not the detective on the case you shouldn't have been there I shouldn't have been there but nobody did anything wrong I mean that was that was a common practice then it was it was the tradition it was how it was done then law enforcement wasn't schooled in memory we weren't schooled in protecting memory treating it like a crime scene were you very care careful methodical about what you do and how you use it and we weren't we weren't taught that in those days but none of these errors explains perhaps the most puzzling part of this story how it is that Jennifer could see Bobby pool in the courtroom and not realize her mistake you're looking into the face of the man who raped you whose face you had studied so intently yes and there's no flicker nothing between you and and Bobby pool nothing nothing and I've gone back there many times trying to think was there was there ever a moment did I ever look at him and think and I didn't Elizabeth Loftus is a professor of psychology and law at the University of California Irvine and an expert in memory she showed me an experiment she says might help explain Jennifer's mistake she asked me to study these faces then after a few minutes she gave me a memory test which of these two faces do you recognize right okay you picked right left you picked left okay I said left but I wasn't 100% sure and then the tricky part oh well I'll tell you why I'm styed because I just picked this one on the left two seconds ago but now I'm not sure cuz those two look very much alike to me but I'm going to tell you the left but I was wrong it was the one on the right Loftus explained how I had been duped you saw this face then I gave you a test where I presented you with an altered face oh my go along with a novel one so I pretty much induce you to pick a wrong face because I don't even have the real guy there it's an altered version and later on when you now have a choice between the altered one and the real one you stuck with your altered left choice this is exactly what happened to Jennifer this can help us understand why Jennifer can be sitting in a courtroom and be looking at Bobby P the original rapist and looking at Ronald cotton and saying saying no it's not pool it's cotton because she has been picking him yeah all long I begin to wonder whether there should ever be eyewitness testimony and trials well because of the tricks that memory plays yeah I I think what's important though is is to understand that know that know it as a police officer as an investigator uh as as attorneys we need eyewitnesses I mean if we couldn't convict based on um an eyewitness that's giving a lot of comfort to criminals we have no choice we have to find ways to make this evidence uh better and that's something Jennifer has tried to do ever since by telling her story to prosecutors police defense attorneys and she's had some success her State North Carolina was the first in the country to mandate reforms by law showing victims lineup photos one at a time and emphasizing that the right answer may be none of the above having lineups conducted by a person who doesn't know who who the suspect is or Not by a person at all the person who committed the crime may or may not be included one system now used in a handful of cities is computer software Mike gden helped develop to have a laptop conduct photo lineups does this person look familiar to you but law professor Rich Rosen says that in the vast majority of places there's been no reform and that needs to change this is something that police officers can and should be in favor of because you're you're not getting the real guy off the street yeah Bobby P raped other women because they went after Ron cotton so Ron is not the only person who suffered from this mistake Ronald cotton now 47 years old has worked hard to rebuild his life he works the late shift in a factory he's been married for 12 years and has a 10-year-old daughter they live in a house paid for with money North Carolina paid him in restitution $10,000 for each of the 11 years he spent in prison when he can he joins Jennifer in her campaign for reforms one of the most amazing things to have come out of this miscarriage of justice is the most unlikely of friendships Jennifer and Ron say they speak on the phone about once a week they're families of friends they say they have a shared bond that is hard for most people to Fathom have people ever met you for the first time when you're together and said kind of cheerily hey how did you two meet yeah that on the airplane a lot oh yeah we're traveling and I usually just you tell them what do you say we look at each other laugh you know and finally we go ahead and and tell them and they have recently co-authored a book in hopes that their story can inform and Inspire others today when you think about what what happened to you that night when you were 22 years old whose face is there nobody's oh my that's that's that to me is one of the most beautiful things is I don't have a face Bobby pool's dead I don't ever have to worry about him ever hurt another woman he died in prison and Ronald cotton is my friend for more on how memories can be contaminated go to 60minutes.com