But this, it turns out, is not true of all memories. In a recent paper, Researchers at MIT and Harvard found that, if a memory can survive long enough to make it into what is called “visual long-term memory,” then it doesn’t have to be wiped out at all. Talia Konkle and colleagues showed participants a stream of three thousand images of different scenes, such as ocean waves, golf courses or amusement parks. Then, participants were shown two hundred pairs of images—an old one they had seen in the first task, and a completely new one—and asked to indicate which was the old one.
Participants were remarkably accurate at spotting differences between the new and old images—96 percent. In other words, despite needing to remember nearly 3,000 images, they still performed almost perfectly.
However, it turns out that they were only this accurate when the new and old images came from different types of scenes (e.g., a golf course and an amusement park). In order to test just how detailed these memories really were, the psychologists also analyzed how participants performed when the images were from the same types of scenes (e.g., two different amusement parks). Since images from the same scene type differ from each other in fewer ways than do images from different scene types, the only way participants would’ve been able to succeed at pointing out differences between these similar images is if they had remembered them with a truly vast amount of detail.
As you might expect, participants were worse at discriminating between same-category images, but not by much, scoring as high as 84 percent. In fact, even when the experimenters increased the number of images that participants initially needed to remember for a given type of scene, participants were still good at distinguishing the old image from the new—with only slight decreases in performance. That said, the fact that memory performance decreased at all shows that, although our memories are very detailed, they are not photographic.
These two separate experiments present a paradox: why are we capable of remembering such a massive number of images with great detail in some instances, and not even a few images after a couple of seconds in others? What determines whether an image is stored in long-term vs. short-term memory?
In a recent review, researchers at Harvard and MIT argue that the critical factor is how meaningful the remembered images are—whether the content of the images you see connects to pre-existing knowledge about them. In the Zhang & Luck experiment, you try to remember meaningless, unrelated colors, and so no connection with stored knowledge is made; it’s as if the white board is scrubbed clean before you get a chance to copy the scribbles into your notebook. But in the Konkle et al. experiment, you see images of recognizable scenes that you already have meaningful knowledge about—such as where the roller coaster is likely to be located relative to the ground. This prior knowledge changes how these images are processed, allowing thousands of them to be transferred from the whiteboard of short-term memory into the bank vault of long-term memory, where they are stored with remarkable detail.
Together, these experiments suggest why memories are not eliminated equally— indeed, some don’t seem to be eliminated at all. This might also explain why we’re so hopeless at remembering some things, and yet so awesome at remembering others.
Are you a scientist who specializes in neuroscience, cognitive science, or psychology? And have you read a recent peer-reviewed paper that you would like to write about? Please send suggestions to Mind Matters editor Gareth Cook, a Pulitzer prize-winning journalist at the Boston Globe. He can be reached at garethideas AT gmail.com or Twitter @garethideas.
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23 Comments
Add CommentWill you guys PLEASE stop comparing the brain to a computer. It is a false and misleading comparison, with no validity, if I remember correctly.
Reply | Report Abuse | Link to thisp.s.
Reply | Report Abuse | Link to thisAnd stop doing experiments based on that false assumption; "well a computer would do This!"
Of course human brain is not a computer, while the opposite is quite true: the most complex computer tries (rather unsuccessfully so far) to imitate human brain. Besides, the verb "compute" means "to determine especially by mathematic means", "to make calculation". Our brains do compute, even if computing is one of the lesser brain activities.
Reply | Report Abuse | Link to thisComparing the brain to a computer is somehow acceptable. It is a simile, for language's sake!
Reply | Report Abuse | Link to thisWell... some tries to make sense through visioning our thought as a mechanism with ubiquitous purpose. But the mind is free, and the purpose may come and go. There is no law that determines a sequential path from individual to individual. Sometimes it may be true, because aspirations are contagious. And memory should be permanent or not, long or short, as we feed our aspirations towards something, simple as that! Why should we be compared to a compurer that has the task to keep any memory?
Reply | Report Abuse | Link to thisA compurer simply is not a free being. It is a machine... an instrument that help us keep unworth things.
Sometimes we may think that we still need those unimportant things.But most of the time we don't, and we get lost, not knowing what to do with so many garbage. And we buy another computer with greater memory. It's alright, it's better have it in digital memory for our comodity and keep our mind to knew things. As we get older, we need it!
Brain IS a computer. But it is not as simple and uniform as the computers we build. When you research a complicated machinery it is quite valid to compare to simpler machines that you know how it works.
Reply | Report Abuse | Link to thisJust because you don't understand how a machine works does not mean it is not a machine... (And a reminder: a machine does not have to be fully deterministic)
" ..Our minds use visual memory..."
Reply | Report Abuse | Link to thisOh hell I'm sunk .... I only have one mind.
Brain is associative memory. Storing and Retrieval happen in associate way. Things/visuals which are associated with the existing memory/knowledge could be retrieved easily; which are not, will be somewhere in memory which could not be retrieved/reached like dangling thing. Over the period for efficiency reason it will fade away. For memory association is the key.
Reply | Report Abuse | Link to thisI have always considered myself to have had a photographic memory when I recall a memory I can literally see the image in my mind. As a kid at school I never did homework yet I was top of my class, I had excellent recall of everything that was taught to us, and everything I read. During exams, if I was unsure of something I had read I would picture the page in mind and re-read it, or I would recall a lesson and remember what the teacher had said.
Reply | Report Abuse | Link to thisI can still recall conversations months later verbatim, if that is not having a photographic memory, what is? In my younger years I travelled a lot, but never took photos but even today I can still recall the places I visited with vivid detail when describing them to others, even recalling specific shops and the order they were in.
Whereas if you asked what I had for dinner last night, I would not be able to tell you, in fact I would never have been able to tell you, why because it is not important enough for me to remember. But if you want to know what I had for dinner at a specific restaurant I have been to at some point I would be able to tell you exactly, why because I hardly ever go to restaurants. I can however tell you what my grandson did today, what he said to me and what he played with, and I could tell you the same for yesterday and last week. Unfortunately I am bloody shocking at remembering names, but I will never forget a face.
I just thought of something brilliant to say, but I forgot what it was.
Reply | Report Abuse | Link to thisTwo independent experiments, one for adults (can read and speak at the same time) and the other for toddlers (can only speak), should be performed. I doubt the so-called visible memory is highly related to other functionality of the brain, particularly, verbal and/or non-verbal communicability.
Reply | Report Abuse | Link to this"This prior knowledge changes how these images are processed, allowing thousands of them to be transferred from the whiteboard of short-term memory into the bank vault of long-term memory"
Reply | Report Abuse | Link to thisAnd these vague, made-up descriptions of what MIGHT be happening, without any empirical evidence to back them up, are the reason I gave up expecting anything substantive from the subject of psychology...
Simple question, What about blind People?
Reply | Report Abuse | Link to thisI recall discussions almost verbatim from my 5th year I am 76 now.
As for what I ate a week ago, not the foggiest idea,its not important. Perhaps I need the storage space to survive in this world?
Then answer this one. We are we inundated with TV and other visual adverts--repeatedly and constantly--why?
Is it not the Monkey see monkey do aspect?
Hi. What this long term memory is for? I think all that was developed to permit adaptation to changing environment, also in our movement, migration, as other animals. Conscious relevance is less important. We need visual LMT to recognize old as safe or dangerous, good feeling or bad feeling, and to enter new sceneries having similarities to good or bad old images and being enough cautious. All happens automatically, visual short and long term is not semantic nor symbolic, not strictly related to consciousness. You can remember all faces and quickly forget names, but not vice versa. And you create unconsciously a "proto-face" or a "proto-city", or a "proto-hotel" first of meeting or visiting or entering it for the first time. That is the istinct, or nose, that evolution gave to all migrant species.
Reply | Report Abuse | Link to this@promytius, i dont know if u r familiar with the term CONNECTIONIS in cognitive science, but if u r not, google it. that is basicly the future of cognitive science and it uses the computers to see if there is congitive relevance between hypothesis and theory and real life(actually, how our brain works). and it is NOT just comparing human brain to computers, it is much more... google it.
Reply | Report Abuse | Link to thisThese results are alright if one looks at then not from a memory point of view but from an orientation/attention perspective. Also the way the brain works is very important because if one tends to, unknowingly, spend most of his/her time thinking about something else the orientation/attention power is very low which means the time one is given to the stimulus is very low. Who has ever forgotten an accident of any sort? This is because the orientation/attention power is at its maximum during these situations and so the event is almost instantly memorized. I think that most of these studies are a bit waste of time as one should first identify the type of brain activity one has before doing any memory studies, but, hey, they may be fun to do them!
Reply | Report Abuse | Link to thisThe experiment does not account for completely trivial events that record like a photo a brief moment and is retained for decades for no discernible reason. I remember, while walking a neighborhood back street in Bern, Switzerland, where I was living for a year, looking up at roofs and the sky.
Reply | Report Abuse | Link to thisThe experiments do not relate to the assumed example of last week dinner. If you tell me in advance that you will be asking me sometimes later about what I had for dinner last week, I will tell you after a week what I ate over the whole week.
Reply | Report Abuse | Link to thisIf you have an unusual encounter while you are having dinner, most likely you will never forget what you were having for dinner.
Reply | Report Abuse | Link to thisMemory; one of the most vital skills in order to lead an effective or independent life. In my youth, attention & memory are two areas that I failed to fully appreciate.
Reply | Report Abuse | Link to thisHOWEVER, the beauty of humanity, is our infinite neurological capacity!!!!!!!!!!!!!!!
Please do not insult the self aware.
Reply | Report Abuse | Link to thisBest wishes,
SkyNet.
Unfortunitly Humans are on a leash, we don't have free will. Everything we do is based of interactions in our enviroment.
Reply | Report Abuse | Link to thisUnforunitly, humans are on a leash, we have no free will. Everything we do is based on the interactions with our enviroment(See, hear, feel, taste, and smell). The only difference between human to human is how we precieve and retain the interactions.
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