National Geographic

Five myths about memory (and why they matter in court)

Psychology is at its most interesting to me when it demolishes what we believe to be true on the basis of common sense, and it does this with alarming regularity. Take our memories. The act of remembering is something we do all the time, so we feel we have an innate understanding of how our memory works. But it is precisely this familiarity that leads us astray. Except for moments where we forget where we placed the keys, we are not privy to the many ways in which our memories let us down. Psychological experiments, however, can make those failures clear, and they have revealed that our memories are more incomplete, inaccurate and easily changed than we would like to think.

Daniel Simons from the University of Illinois and Christopher Chabris from Union College Schenectady have done a large survey to look at our misconceptions about memory. They asked a nationally representative sample of over 1,800 Americans to say how much they agree with various statements, and compared their answers to a small group of experts – professors, polled at a psychology conference, who had been studying memory for more than 10 years. This slideshow shows what they found.

On the whole, 60 percent of people agreed with statements that the experts almost totally rejected. These misconceptions can have severe consequences, when they influence the outcomes of court cases. As Simons and Chabris write, “This discrepancy between science and popular beliefs confirms the danger of relying on intuition or common sense when evaluating claims about psychology and the mind. Accordingly, scientists should more vigorously communicate established and uncontroversial results (alongside new and surprising findings) in a way that leads to broader public understanding.”

Would you send someone to jail on the basis of video footage shot with a low-resolution camera whose lens has dirty marks around the sides and a massive hole in the middle? Probably not, and yet that is basically what eyewitness testimony is. While it looks like we see the world in vivid detail, like the display on a high-definition television, that’s largely because the information from our eyes is heavily processed by the brain. It covers the missing information in our blind spot, and smoothes over the lack of detail around the edges. It’s a filtered version of reality.

This is hardware problem, but the software has glitches too. Our view of the world is sensitive to our expectations, our desires and where we assign out attention. Simply put, we see what our brain wants us to see. The camera metaphor implies a passive process where we switch on our memory, and it dutifully records away. The reality is very different.

As we’ve seen, the memories of eyewitnesses can be fickle things. But confident eyewitnesses can sway the minds of juries. There is a grain of sense in this – look at a large group of people and they’re generally more accurate if they’re more confident in their memories. But for any individual, confidence is a poor gauge of accuracy because we all differ in how confident we are in the first place. The consequences of overly relying on the confidence of memory can be catastrophic. Eyewitness misidentifications are the single greatest reason why innocent people are convicted for crimes they did not commit.

People often imagine their memories to be like vast libraries, where information is written down, filed away, and then brought back when it’s needed (or lost in some dusty shelf). But the act of remembering is more complicated than that.

Every time we bring back an old memory, we run the risk of changing it. It’s more like opening a document on a computer – the old information enters a surprisingly vulnerable state when it can be edited, overwritten, or even deleted. It takes a while for the memory to become strengthened anew, through a process called reconsolidation. Memories aren’t just written once, but every time we remember them. This might be useful in terms of conquering traumas and phobias, but it’s much less helpful in a courtroom.

People generally believe that even if we focus our attention on a task, we will be distracted by surprising things going on around us. Time and again, Simons and Chabris have shown that this isn’t true. If you are one of the few people left who hasn’t heard of their famous illusion, try this or one of many other similar tests. On the surface, this seems to be a misconception about attention rather than memory, but obviously, we only explicitly remember things that we see in the first place.

In courtrooms, a person’s honesty can be called into question is it’s deemed that they should have noticed something obvious going on around them. Such a case happened in 1995. While chasing after a suspect, a Boston policeman called Kenneth Conley ran directly past several other officers mistakenly beating another man. Conley said he didn’t see the beating, to great disbelief. He was indicted for perjury and obstruction of justice, and sentenced to 34 months in prison. Through a staged experiment, Simons and Chabris showed that it’s entirely possible to run past a vivid beating if your mind is on other thingsThis one has few practical implications, but it is interesting nonetheless. Amnesia is often used as a convenient plot device in films and TV, where people suddenly lose all memory of their names or the past lives. This can happen – it’s called a fugue state, but it’s very rare. The film Memento has a more accurate portrayal of amnesia, or at least the variant known as “anterograde amnesia”. As in the film, people with this condition lose the ability to entrench new memories, losing new information and experiences after a short space of time. But even in this film, the hero loses a sense of his own identity, something that happens very rarely in real life.

People can also suffer from “retrograde amnesia”, where they lose older memories, particularly those that happened immediately before an accident or injury. It typically occurs alongside anterograde amnesia, and is rarer as a stand-alone condition.

Reference: :Simons, D., & Chabris, C. (2011). What People Believe about How Memory Works: A Representative Survey of the U.S. Population PLoS ONE, 6 (8) DOI: 10.1371/journal.pone.0022757

There are 22 Comments. Add Yours.

  1. Tom Hartley (@tom_hartley)
    August 5, 2011

    The conclusion that scientists should communicate their uncontroversial findings more vigorously is spot on.

    Unfortunately it is hard for these established findings to gain space in the news agenda. But perhaps there is a place for bloggers such as yourself to explore the background and consensus in more detail.

    The world’s largest ever memory conference is ending today in York. I would be happy to try to arrange a brief chat with one of the experts here, if you are interested in following up Simons and Chabris’ suggestion!

    http://www.york.ac.uk/conferences/icom5/

  2. nico
    August 5, 2011

    Although I agree your article makes the point that scientists should communicate their findings as widely as possible, in this case I think the onus is also on the legal profession.

    It has been known for some time that memories are quite malleable, and in a system where testimonies can carry a lot of weight I would expect that the legal profession keeps an eye on the latest research (if they don’t already), and draws up guidelines accordingly.

  3. Daniel
    August 5, 2011

    Wow. So most people really think their brains are like video cameras and memories don’t change? That’s frightening. With the exception of the last slide, I would have expected the majority of the public to answer similarly to what the experts said. I’m going out on a limb here but I venture to guess that if this survey was done in a country other than the US, the outcome may be quite different. If these results are indeed representative of the US population, they also might help explain the faith and trust Americans have in a judicial system in which untrained lay people get to decide whether someone should be executed or face life in prison, which to me as a European is simply shocking.

    P.S.: May I suggest to add a line to this box warning people that if they forget to fill out a required field, everything they wrote will be gone and it’s a good idea to select all and copy it before hitting the Submit button?

  4. Brin
    August 5, 2011

    it’s a good idea to select all and copy it before hitting the Submit button?

    That’s always a good idea.

  5. Jeremy
    August 5, 2011

    What you can’t remember what you typed? : p

  6. Boris
    August 5, 2011

    Such findings need to get through to public. One can smile at what others believe to be true when it is not, but no one would like to be convicted of crimes one did not commit thanks to that belief. I’ve posted the findings in my blog in Russian.

  7. Dan Simons
    August 5, 2011

    Niko — many in the legal community are aware of the research. What they didn’t really know for certain is how pervasive some of these mistaken common-sense intuitions are. In some states (Louisiana, for example), expert testimony by memory researchers has been disallowed on the grounds that it’s not established enough or that it’s obvious. We’re hoping that this evidence from a representative sample helps to override those jurists’s intuitions about intuitions…
    -Dan

  8. Kari Kenefick
    August 5, 2011

    A midwestern law school enlists a nonstudent to dash into a room full of first year law students, grab a purse or backpack and run off. The instructor then asks the class, 70-100 students, to write down a description of the “perp”. The results are amazingly far from accurate of the “perp’s” appearance. Innocence Projects around the US know that eyewitness testimony, even firsthand, is notoriously unreliable; memory is colored by the excitement (terror? surprise?) of certain events.

  9. Harold
    August 5, 2011

    The cynic might say that prosecutors don’t want jurors to know or understand these misconceptions about memory as it might make their jobs harder. It would certainly have changed the deliberations in 12 Angry Men, for example.

    I remember reading in a similar article to take pictures of an event (mugging, car accident, etc.) if possible, and if not, to write down all you can as soon as possible and then defer to those notes. It’s all too easy to misremember details as time passes, not to mention the possibility of suggestive questioning altering your memory.

  10. Dorothy Bishop
    August 6, 2011

    Readers interested in this topic will find this long-form blog about Beth Loftus by Will Saletan in Slate is astonishingly good
    http://www.slate.com/id/2256089/

  11. Andrew Wilson
    August 6, 2011

    I’m more worried about the percentage of experts not getting these right.

  12. IW
    August 8, 2011

    I had a really good comment but memory fails me….

  13. Brian
    August 8, 2011

    I’m not a psychologist, but I would guess one reason these myths persist is that articles about them do a poor job of presenting a better alternative. For example, if there were a wide misperception that Montreal is the capital of Canada, I wouldn’t try to correct that just by telling people Montreal is not the capital of Canada. I would tell them that Ottawa is the capital. If you tell them memory doesn’t work like a video camera but don’t give them an alternative analogy, then you shouldn’t be surprised if they keep thinking it works like a video camera.

  14. PJ
    August 10, 2011

    Brian has a good point, but I’m not sure I can think of a better analogy.

    Kind of like RAM, in that it fades if you don’t periodically refresh it (read it, and write it back out).

    Also, every time you bring it into your working memory it gets changed slightly, and those changes get written back to the long-term storage.

    It’s like vector-based graphics: Instead of storing an image pixel-by-pixel, you store instructions for making the image.

    Fidelity isn’t usually important, so your brain only keeps the parts that it thinks are important. (Do most people know what “lossy compression” means?)

    If you try to recall something that wasn’t completely stored, your brain tries to fill in the blanks with whatever makes the most sense. Then it incorporates the interpolated data into the memory, just as if it were part of the original. It’s difficult to tell whether any part of your own memory is something you experienced or something you made up. That strikes me as something people would find hard to swallow, no matter how many papers are published in reputable journals demonstrating it. And I can’t think of any other system that works like that.

  15. AntonyIndia
    August 10, 2011

    Some people DO have a photographic memory: Kim Peek (the real Rainman) comes to mind;
    so it is possible. How does this affect the “Scientific consensus” on this topic?

  16. Bob Snyder
    August 10, 2011

    @AntonyIndia, that is not scientific fact. Quite the contrary, it is highly debatable whether anybody has that type of memory or not. But even in the unlikely event that a handful of people do have photographic memories, the article was about the general public and the misconceptions they have about their own memories.

  17. Jimmy Bones
    August 13, 2011

    I’ve never studied psychology in my life and realise how inadequate our brains are at recalling events and other visual/aural etc. information and how it changes over time. I’ve experienced it personally many times and try to analyse it to give myself a good and healthy amount of self doubt (or at least remain somewhat critical of my own memories, be that general information or recalling events). I find it pretty crazy that some people trust there brains so much and really think that it’s important for people to maintain a good amount of humility.

  18. badnicolez
    August 14, 2011

    Wouldn’t even a “photographic” memory be just that: a series of snapshots (however accurate) vs. a video/movie-like recollection?

    Perhaps a test using these questions should be given to potential jurors prior to serving on a case. If you fail, you cannot serve unless you acknowledge your utterly false assumptions about the accuracy of memories.

  19. Iain
    August 14, 2011

    People are stupid. Get that through your heads.
    Your vision is not a camera. Not at all, the eye sees, but it doesn’t record, the brain does that, BUT the brain filters its information. Unlikely visual events are for the most part ignored. There was an experiment where something interesting was going on, a person in Gorilla suit sauntered onstage, took something non essential to the scene and moseyed off. 90% of the people didn’t notice the Gorilla! It was filtered out.
    So your eyewitness is unreliable by definition, unless of course they have a video of the event. Which then makes it a video recording, not an eyewitness.
    PJ the only way that human memory represents RAM is that it is random access.

  20. floodmouse
    August 17, 2011

    I just watched the “Nova” episode on memory on-line. They use the example of stage magicians Penn & Teller, who can distract the audience with hand motions to prevent them from noticing a movement off-center that would otherwise be very obvious. (Reminds me of Iain’s gorilla.) I think the researchers should have re-worded their survey question about hypnosis: Not “can” it improve memory, but “does it usually” improve memory? Hypnosis has mixed results depending on the subject and the situation. I personally believe hypnosis might sometimes improve memory, but it very often distorts memory instead. The wording of the questions might change the statistical results.

  21. Glen
    August 18, 2011

    at least 90%, possibly more of all wrongful convictions involve witness identification.
    If I’m evber on a jury, and it is a case involving any kind of sexual assault or involving a known weapon, as far as I am concerned, no DNA, no proof!!

  22. Peter
    August 20, 2011

    Our peripheral vision is fuzzy at best; what light does fall on the fovea is then filtered by the brain and stored with “lossy compression”. We can completely, though unconsciously, ignore the gorilla. Upon uncertain recall, we re-evaluate the data,and store the changes as original. Hypnosis can help up remember things that never happened. (Alien abductions, for example.) I agree with Glen; eyewitness testimony would almost certainly not sway me. I find it amazing that I can remember anything at all!

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