memory
dmunger | March 5, 2009A few years ago we discussed a fascinating study which appeared to show that the main reason we stop eating at the end of a meal isn't because we "feel" full. Instead, we simply see that we've finished eating the food in front of us, so we stop. We don't eat more an hour later because we remember we just ate.
In that study, led by Paul Rozin, experimenters provided two amnesic patients with two meals separated by just 15 minutes. They both did not recall eating the previous meal due to their medical condition, and each of them ate both meals as if they hadn't had anything to eat.
But maybe…
neurophilosophy | March 2, 2009Despite occuring only rarely, amnesia (or memory loss) has featured often in Hollywood films for almost a century. By 1926, at least 10 silent films which used amnesia as a plot device had been made; more recent productions, such as 50 First Dates and Eternal Sunshine of the Spotless Mind, are therefore part of a well established tradition.
In a review published in the British Medical Journal in 2004, clinical neuropsychologist Sallie Baxendale of the Institute of Neurology in London points out that cinematic depictions of amnesia are consistenly inaccurate, and usually "bear no relation…
dmunger | March 2, 2009When I'm writing a post for Cognitive Daily (or doing almost any kind of writing, for that matter), I try to keep outside distractions to an absolute minimum. I even have an application on my computer that shuts off all access to the internet for a specified period of time. I find most music distracting, but sometimes I'll play a Mozart piano concerto, which seems to help focus my attention (see here for a possible explanation).
Some people, however, seem to be able to be incredibly productive despite a huge number of distractions -- Twitter status updates, email, crying babies, you name it.…
dmunger | February 26, 2009Last week, we presented research by Miranda Scolari's team about visual expertise and visual short-term memory. Their conclusion: "experts" don't have a larger visual memory capacity than non-experts, they just have the ability to process more details. Scolari's team was working under the assumption that all humans (or at least all the students in their experiment) are face-recognition experts.
It's true: we're amazingly good at recognizing faces we've seen before. Think how much easier it is to remember a face you've seen than it is to remember the name that goes with the face. But surely we…
dmunger | February 23, 2009One of my most vivid memories from middle school was in English class. The class wasn't paying attention to the teacher -- we were chattering during "work time" and she wanted us to stop and return to a full-class lesson. So she shouted "SEX!" We all shut up immediately and stared at her in disbelief. Then she said, in a calm, normal voice: "Now that I've got your attention ..." and proceeded with her lesson. It worked great -- except for one thing. I have no recollection of what she actually taught us that day.
This brings up an interesting point: Teachers are often tempted to bring up…
neurophilosophy | February 19, 2009Working memory refers to the process by which small amounts of information relevant to the task at hand are retained for short periods of time. For example, before cellular phones became so ubiquitous, calling someone usually involved first finding the number and then remembering it for a just few seconds by repeating it to oneself several times. Once the digits had been dialled, they are immediately forgotten.
Very little is known about the neural mechanisms underlying working memory, but very recently some advances have been made. Last month, a group from the University of Texas Medical…
dmunger | February 18, 2009Take a look at this quick video. You'll see a set of six small images, arranged in a circle, for 1 second. Then the screen will go blank for 1 second. Finally, one image will reappear in the place of one of the first six pictures. Your job: indicate whether the final image is the same or different as the image that originally appeared in that same spot.
Click here to view the movie (QuickTime required)
In principle, this should be an easy task, right? Your visual working memory can hold around six items at a time, so it shouldn't be hard at all to remember if the new picture is the same as…
edyong | February 17, 2009The mainstream media are just queuing up to fail in their reporting of the propranolol story from a couple of days ago. To reiterate:
Propranolol is commonly used to treat high blood pressure and prevent migraines in children. But Merel Kindt and colleagues from the University of Amsterdam have found that it can do much more. By giving it to people before they recalled a scary memory about a spider, they could erase the fearful response it triggered.
The critical thing about the study is that the entire memory hadn't been erased in a typical sci-fi way. Kindt had trained the volunteers…
edyong | February 16, 2009The wiping of unwanted memories is a common staple of science-fiction and if you believe this weekend's headlines, you might think that the prospect has just become a reality. The Press Association said that a "drug helps erase fearful memories", while the ever-hyperbolic Daily Mail talked about a "pill to erase bad memories". The comparisons to The Eternal Sunshine of the Spotless Mind were inevitable, but the actual study, while fascinating and important, isn't quite the mind-wiper these headlines might have you believe.
The drug in question is propranolol, commonly used to treat high…
neurophilosophy | February 9, 2009Most of us have experienced the vague feeling of knowing something without having any memory of learning it. This phenomenon is commonly known as a "gut feeling" or "intuition"; more accurately though, it is described as implicit or unconscious recognition memory, to reflect the fact that it arises from information that was not attended to, but which is processed, and can subsequently be retrieved, without ever entering into conscious awareness.
According to a new study, our gut feelings can enhance the retrieval of explicitly encoded memories - those memories which we encode actively - and…
neurophilosophy | February 2, 2009During the first half of the twentieth century, the American psychologist Karl Lashley conducted a series of experiments in an attempt to identify the part of the brain in which memories are stored. In his now famous investigations, Lashley trained rats to find their way through a maze, then tried to erase the memory trace - what he called the "engram" - by making lesions in different parts of the neocortex.
Lashley failed to find the engram - no matter where he made a lesion, his experimental animals were still able to find their way through the maze. As a result, he concluded that memories…
edyong | January 26, 2009People diet for many reasons - to fit into clothes, to look more attractive, or for the sake of their health. But to improve their memory? It's an interesting idea, and one that's been given fresh support by Veronica Witte and colleagues from the University of Munster in Germany.
Witte found that elderly people who slash the calories in their diet by 30% were better able to remember lists of words than people who stuck to their normal routine. It's the first experiment to show that cutting calories can improve human memory at an age when declining memory is par for the course.
The benefits…
edyong | January 18, 2009
You swallow the pill. As it works its way through your digestive system, it slowly releases its chemical payload, which travels through your bloodstream to your brain. A biochemical chain reaction begins. Old disused nerve cells spring into action and form new connections with each other. And amazingly, lost memories start to flood back.
The idea of a pill for memory loss sounds like pure science-fiction. But scientists from the Massachussetts Institute for Technology have taken a first important step to making it a reality, at least for mice.
Andre Fischer and colleagues managed to restore…
dmunger | January 7, 2009Every year about this time, we start thinking about an exciting television event: the Super Bowl. I'm excited because it's the biggest football game of the year. The rest of the family just likes to watch the commercials. No doubt, some of those commercials are hilarious, and there's often more conversation about the commercials than the game itself. Companies spend millions buying advertising time, and millions more developing commercials that will stand out from the pack on Super Bowl Sunday. Other than watching your favorite team lose, there's nothing more disappointing than seeing an old…
dmunger | December 18, 2008[This is our synchroblogging post in honor of PLoS ONE's second birthday. Why not write your own?]
Ever wonder whether it's better to study all night before a big exam, or to get a good night's sleep, but maybe not have a chance to go over all the material? We know that memory consolidation can occur in sleep, but we also know that those extra hours studying can do some good. And then there's the issue of false memories: who hasn't had the experience of being completely convinced their test answer is correct, only to learn that it's 100 percent wrong?
Inducing false memories is surprisingly…
dmunger | December 11, 2008Yesterday's post showed that our memory for objects depends on the background information available when we first see the object: If you see a toy in a room, you remember it better later if you see it again in the room. Being in the same position in a blank picture of the room doesn't help.
So what about the scene is helping us remember the object? It could be things in the immediate area of the object: are we remembering the precise object/background relationship? In our example, maybe we're remembering exactly how the propeller and the gear interact with the background:
In 2003,…
dmunger | December 10, 2008Change blindness is a truly remarkable phenomenon. There are so many ways that the human perceptual system can be tricked into missing a change that appears right before our eyes, that it's sometimes astonishing that we aren't constantly running into walls or misplacing the basics of life -- our car keys, wallet, our what were were planning on eating for dinner. If you've never seen a demonstration of change-blindness, I'd suggest checking out some of the posts we've written about it before (For example, here, here, and here).
So why don't we notice these sorts of changes? This video, based…
neurophilosophy | December 5, 2008The amnesic patient known as H.M., who is the best known case study in neuropsychology, has died, at the age of 82.
H.M., whose full name has now been revealed as Henry Gustav Molaison, lost completely the ability to form new memories following a radical surgical procedure to treat his severe and intractable epilepsy.
The operation was performed in 1953 by William Scoville, a neurosurgeon at Hartford Hospital in Connecticut. Using an experimental technique he had recently developed, Scoville removed both of H.M.'s hippocampi in their entirety, together with some of the surrounding structures…
dmunger | December 4, 2008Can you hear colors? Can you see sounds? Do words have colors or images associated with them? It may sound impossible, but there are many documented cases of people who experience all these things. We've discussed it before on Cognitive Daily, and even found some limited evidence of similar phenomena among the general population. Collectively, these experiences are called synesthesia. Perceptions have many modalities corresponding to different ways of experiencing the world. The most well-known modalities are the five senses, but "words" or "numbers," or "colors" may also be considered…
dmunger | November 24, 2008Boundary extension is a phenomenon we've discussed a lot on Cognitive Daily. It's typically described as a memory error: We remember scenes as having bigger boundaries than what we originally saw. Take a look at these two pictures of Jim:
If you only saw picture A by itself, then later you'd remember seeing a picture that looks more like picture B. If you look at them side-by-side, it's easy to see that picture A is cropped closer than picture B, but if you see the pictures separately, then it's likely you'll misremember the first picture has having broader boundaries than it really has.…