Memory
May 8, 2008
Category: Memory • Research • Social
Anton races home at speeds well in excess of the speed limit. He's rushing to beat his parents home so that he can hide their anniversary present so it will be a surprise. Suddenly, he hits a slick patch and runs his car off the road an into a tree. He's okay, but the car is totaled and his parent's surprise anniversary party is ruined.
How much is Anton to blame for the accident? If you had to rate it on a scale of 1 to 10, maybe you'd give him a 7. After all, he was just trying to do something special for his parents.
But what if instead of hiding an anniversary present, Anton was rushing home to hide his cocaine stash? Would you now say he's more to blame for the accident? You might not when the two alternatives are placed side-by-side, but when Mark Alicke told the two versions of this story to different groups, the cocaine group rated Anton as more blameworthy than the anniversary present group.
Alicke's study provided the foundation for an array of studies on the effects of social evaluations of individuals on apparently unrelated events, and even factual recollections about episodes.
But when a team led by David Pizarro addressed this question, no study had yet shown that unrelated details about a person could literally affect witnesses' accuracy in recalling that person's actions. The researchers presented a simple story to 283 college students. The story described a person named Frank entering a restaurant, paying with cash for a drink, then ordering a three-course meal, receiving a cell phone call, and leaving without paying the $56.43 bill.
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Posted by Dave Munger at 3:47 PM • Comments (11)
April 29, 2008
Category: Face perception • Memory • Research • Social
Humans are exceptionally good at recognizing faces they've seen before. It doesn't take much study to accurately recall whether or not you've seen a particular face. However, this pattern breaks down when faces come from unfamiliar races. A white person who lives primarily among other whites will have more difficulty recognizing Asian faces, and vice versa.
But how engrained is this difference? How much experience with other-race faces do we need to have before we can recognize them as well as same-race faces? Is learning to recognize other races as difficult as recognizing any new category of objects -- cars, say, or birds? When we do learn to recognize other-race faces, do we really know them as well as more familiar races?
While it has been known for some time that we can learn to recognize other race faces as well as our own, this last question hasn't been studied as thoroughly. Maybe in more difficult tests of recognition, we wouldn't do as well with different-race faces.
To explore this question, a team led by Elinor McKone developed a clever set of three experiments. In the first experiment, white Australian students were exposed to 32 different faces -- some white, and some Asian -- for three seconds each. After a brief break where they were distracted with multiplication problems, they were tested on a set of 64 pictures -- 32 they had seen before, and 32 new pictures. Their job was to say which were old and which were new. As expected, the students were significantly more accurate with same-race faces compared to different-race faces. This showed that with brief exposure, different-race faces aren't recognized as well as same-race faces.
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Posted by Dave Munger at 3:17 PM • Comments (15)
March 28, 2008
Category: Face perception • Memory • Research
[This post was originally published in November of 2006]
Do you recognize the person depicted in this video? (QuickTime required; the movie is below the fold)
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Posted by Dave Munger at 7:30 AM • Comments (10)
March 18, 2008
Category: Learning and testing • Memory • Research
My first introduction to psychology was in a required social science class in college over 20 years ago, reading Sigmund Freud's Introductory Lectures on Psychoanalysis. The experience made me think I'd better be careful if I ever had kids: I didn't want them telling their psychoanalysts how my misadventures in early parenting had scarred them. But while true Freudian psychoanalysts are becoming rarer with each passing year, one of the concepts he advocated has persisted for more than a century: transference.
Freud believed that transference was a fundamental part of the psychoanalytic process, sometimes achieved only after many years of careful therapy. Transference occurred when the patient substituted his or her relationship with the therapist for the troubling past relationship (often with a mother or father figure) that was the root of the patient's problems. After transference occurred, the patient was much more inclined to remember the key moments that had caused their neurosis, leading eventually to a resolution and cure.
More recently, Susan Andersen and her colleagues have offered a new explanation for transference. Far from being the product of a difficult negotiation between patient and therapist, the application of transference is much more like a stereotype, and is experienced all the time by healthy individuals. For transference to occur, all that is necessary is to encounter a person that reminds you of a significant person in your life -- a family member, friend, or lover. Transference in this view is simply the misapplication of the traits of your significant other to this new person.
In a typical study, Andersen's team has a volunteer describe an important person in their life. Then after some delay, they read a description of a new person that has some similarities with their friend or loved one. In a subsequent memory test, they tend to misapply traits of their loved one to the new person -- traits that were never present in the description they read.
Is Andersen's transference the same as what Freud describes?
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Posted by Dave Munger at 2:55 PM • Comments (4)
February 13, 2008
Category: Memory • Movement and exercise • Perception • Reasoning • Research
Which of these two pictures is more memorable?
The shot on the left is interesting primarily because Nora's in it -- if it was just a picture of a muddy trail, it wouldn't be notable at all to most people. The shot on the right is a dramatic mountain scene that you might remember even though (or perhaps because) there's not a human in sight.
But a seasoned hiker might be more interested in the photo of the muddy trail, which gives more information about the difficulty of the hike than a panoramic shot. Just as expert chess players are good at remembering the position of chess pieces on the board, maybe expert hikers are better at remembering details about trails than novice hikers.
The classic study of expert and novice chess players was conducted in 1973 by William Chase and Herbert Simon, and found that chess experts could remember configuration of chess boards better than novices -- as long as the chess pieces were arranged in a plausible game configuration, and not just randomly arrayed.
Since then, dozens of studies have found that experts in a variety of fields have better memory for things related to their area of expertise, from football formations to chest X-rays. But according to a research team led by Satoru Kawamura, all of these results can be explained by perceptual chunking: Experts are better than novices at lumping information into manageable groups. Hiking scenes, they argue, aren't easily chunked in the same way. Do expert hikers still have better memory for scenes relevant to hiking?
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Posted by Dave Munger at 11:06 AM • Comments (17)
February 5, 2008
Category: Attention • Language • Memory • Research
A particular source of dread for politicians is how to respond to negative campaigning or other information impugning their character. By responding, they might only bring attention to an issue that voters hadn't even recognized: "Contrary to my opponent's claims, I have stopped beating my wife, and I haven't consumed more than a fifth of hard liquor in a single sitting."
Worse, many studies have found that even unequivocal denials fail to register in memory. In one study, participants read a report about the possible cause of a fire: a room full of oil paint and pressurized gas cylinders. Later in the report an addendum indicated the room was actually empty, but when questioned, most respondents still believed that the flammable materials in the room had caused the fire.
Clearly there is considerable power in being the first to assert the "truth." But surely people are capable of revising their opinions based on factual evidence. Some of the greatest works of literature in history hinge on readers recognizing that an early impression of a character turned out to be false, from Oedipus learning that he has married his mother to Elizabeth Bennet realizing that Mr. Darcy isn't actually a rat and a scoundrel. If we go on thinking Darcy is proud and prejudiced, we miss the whole point of the novel.
So why is it that sometimes we go on thinking Senator so-and-so is a wife-beater despite his denials but other times we re-evaluate our position based on the evidence? Are we just paying more (or less) attention? David Rapp and Panayiota Kendeou had student volunteers read 24 different "stories" involving a character who demonstrates a trait like sloppiness or laziness, which then may be immediately contradicted in the story. The stories were all just 13 sentences long, and each sentence was displayed one at a time on a computer screen. Here's the beginning of a sample story:
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Posted by Dave Munger at 4:07 PM • Comments (10)
January 31, 2008
Category: Memory • Perception • Research
When we watch a movie, we're usually not conscious of the cuts made by the editor. The camera angle may change dozens of times during a scene, and we follow along as if the flashing from one viewpoint to another wasn't at all unusual. You might think this is just because we've been accustomed to watching TV and movies, but researchers have found that even people who've never seen a motion picture have no difficulty following along with the cuts and different camera angles in a video.
But little research has actually been done on the impact of changing camera angles in a movie on our perception and memory of a scene. While cutting abruptly between camera angles seems unnatural, moving a camera from place to place while filming can be quite realistic: after all, people walk around all the time; their own viewpoint is constantly changing. One study did find that people have better memories for a static scene filmed with a moving camera, compared to two still shots taken from the beginning and end- points of the camera's motion.
But what about dynamic scenes? If the people in a scene are themselves moving, will an abrupt cut to a new camera angle disorient the viewer? Filmmakers have found anecdotally that a 180-degree shift in a cut can be extremely disorienting -- that's why when watching a football or basketball game we usually see the action from just one side of the field or court. But do smaller cuts have a similar impact?
A team led by Bärbel Garsoffky showed computer-generated ten-second movies of a half-court basketball game to 12 volunteers. In some of the movies, the camera maintained a steady position either at the side of the court or midcourt, looking straight at the hoop, like this:
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Posted by Dave Munger at 1:53 PM • Comments (28)
January 24, 2008
Category: Language • Memory • Research
When you know something, is that different from remembering? Both types of thoughts are clearly part of the memory system, but is there really any difference between the two concepts? We often use the two terms nearly interchangeably: I might say "I remember Suzanne had her purse when we left the restaurant because I saw her pull out her phone at the bus stop," but I might equally say "I know Suzanne had her purse on the bus because she was gabbing on the phone the whole ride home."
But the subtle linguistic difference between the two terms isn't meaningless. We might know George W. Bush is President, but if we remember that James Garfield was the President who preceded Chester A. Arthur, it's likely due to a specific recollection from 11th grade history class (either that or we attended Garfield High School).
We say that we know something because of a general sense that it is true, but we remember something because we recall a particular incident. Psychologists have actually been able to measure the distinction between the two, simply by asking test subjects whether they know or remember the answer to a question (and explaining what they mean by the two terms).
So how does a "know" memory get formed? Are there circumstances when we're more likely to form a "remember" memory? Can one sort of memory transform into the other? Or is the difference between know and remember simply an artifact of the fact that we remember some things better than others? A team led by John Gardiner had volunteers listen to a set of 60 different words, half of them in a male voice and half in a female voice. They rated each word for clarity and pronounceability on a scale of 1 to 5. Then they played a computerized board game for 20 minutes as a distraction. Finally they were tested on which words they remembered.
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Posted by Dave Munger at 2:51 PM • Comments (9)
January 3, 2008
Category: Language • Learning and testing • Memory • Research
During my brief tenure as a high school teacher, one common suggestion I got from supportive colleagues was to "make your tests teaching tools." "That's often the only time you've really got your students' attention," they suggested, "so don't neglect the opportunity to teach them something."
What they meant is that you shouldn't use misleading or false information in tests as a "trick" to make sure they grasp the material: your test might be the only thing students remember from a unit.
But there's another reason testing is important for learning. For decades researchers have known that more is often learned during testing than traditional "learning." If, for example, students must learn 20 spelling words for a test, in many situations they'll remember the 10 words they were *actually* tested on better than the others.
If I quiz Jim on his Spanish vocabulary words every day, he does better on tests than if he studies on his own. This might be more of a reflection of the quality of his study time than a testing effect, but it still demonstrates the power of testing in aiding learning.
But how exactly does the testing effect work?
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Posted by Dave Munger at 1:45 PM • Comments (13)
December 31, 2007
Category: Attention • Memory • Perception • Research
[Originally posted on November 7, 2005]
What does it mean to have a gut feeling that you remember something? You see someone you recognize in a coffee shop. Do you remember her from high school? Or maybe you saw her on television. Could she be the manager of your local bank? Perhaps you don't know her at all ... but you've still got a feeling you do. What's that all about?
One theory of memory proposes that what we remember depends on our expectations. We're less likely to remember our old classmate at the coffee shop than at the high school reunion. At the bank, we might greet the manager by name, but we only get a vague sense of recollection when we see her in the checkout line at the grocery store. So what cues that sense of expectation? If the grocery store pipes in the same music they play at the bank, will we remember her then? What if it turns out she's not the bank manager, but another woman about the same height who happens to own the same blazer? Does the music help us notice the difference, or just make us more likely to ask a complete stranger about the status of our mortgage application?
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Posted by Dave Munger at 9:56 AM • Comments (2)
December 13, 2007
Category: Attention • Memory • Research
The human perceptual system is able to enforce a large array of illusions on our conscious experience. Most importantly, we hold the illusion of a complete and vivid picture of our surroundings, while in fact we selectively ignore nearly everything we see.
There's a good reason for this, of course: focusing on the task at hand generally consumes nearly all of the processing power our brains have to offer. If we need to shift our focus to another aspect of our surroundings, we can do it nearly instantaneously. But how do we decide which items to pay attention to? There are a couple possibilities. We might pay attention to the kind of things we've seen or heard about recently (priming). But the process might be more conscious: we pay attention to the kind of things we intend to do something about. For example, if I'm driving a car, I might notice red things more often than other colors, since I'm on the lookout for red traffic signals indicating that I need to stop.
So how do you find out if priming or intention is a more important factor in what we pay attention to? The first thing is to create a task that maxes out your multi-tasking ability. Take a look at this video (QuickTime required). You'll see one word flash while you hear another word. Your job is to ignore the audio words, snap your left hand if the printed word is pleasant, snap your right hand if the printed word is unpleasant, and knock on the table if the printed word is an animal. The audio words are just there to make the task more difficult; focus on the printed words:
A team led by Richard Marsh asked 103 college students to complete a similar task, but it went on for much longer: there were 100 trials, with just four animals over the course of the entire task. Pleasantness was rated on the using a scale on the computer, and the student volunteers had to press the slash key whenever an animal name appeared.
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Posted by Dave Munger at 2:32 PM • Comments (2)
August 23, 2007
Category: Attention • Memory • Perception • Research
Memory is a curious thing, and visual memory is even more curious. In some ways, we don't remember much about the scene that's right in front of us. As countless
change blindness studies have shown, we often don't notice even obvious changes taking place in a scene. Other studies have concluded that visual short term memory has a capacity of just three or four objects.
Yet I have vivid visual memories of scenes I have only glimpsed for a few seconds: A deer below the rim of the Grand Canyon; Michael Jordan draining a three-pointer to win the NBA championships; the standing ovation our daughter received at the school play. If I could only retain three or four of the items in those scenes in short-term memory, why are my long-term memories so vivid? How could they have ever
become long-term memories if my short-term memory couldn't even contain them?
Some researchers have suggested that any additional details in those memories are filled in by verbal descriptions -- the "gist" of the scenes, instead of the actual visual imagery. But this explanation doesn't match up with the rich visual memories I have of some places. Could some other process be responsible for the richness of visual memories?
There is some evidence that visual memory for scenes increases with longer viewing time. But can we remember more than the four items supposedly retainable in short-term visual memory?
David Melcher showed photos of scenes to volunteers for periods ranging from 5 to 20 seconds. But he also added a twist:
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Posted by Dave Munger at 1:59 PM • Comments (10)
August 21, 2007
Category: Learning and testing • Memory • Perception • Research
When you look at a scene: a building, a park, a mountain, your visual system processes the information differently from when you look at a single object: a face, a pen, or a coffee mug. For example, this first image is from our trip to Prague this past summer:
When you look at this picture, your eye might move first to the bridge, then to the lampposts on the bridge, to the castle in the background, to the overhanging limbs. The next picture is much simpler:
It's a coffee mug, plain and simple. There's not much left to do with it. There are three regions of the brain that respond more strongly to scenes than to objects: the parahippocampal place area (PPA), the retrosplenial cortex (RSC), and the transverse occipital sulcus (TOS).
But do these areas respond differently to different types of scenes? That's what a new study by a team led by Russell Epstein (and including Steve Higgins of Omni Brain) sought to uncover.
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Posted by Dave Munger at 1:27 PM • Comments (4)
June 7, 2007
Category: Memory • Perception • Research • Video Games / Technology
This is a guest post by Daniel Griffin, one of Greta's top student writers for Spring 2007
How well do you think you can navigate through these woods?
How about when your field of view is significantly reduced?
When external information such as sight is decreased, our ability to make our way to a goal while avoiding obstacles will understandably be impaired.But when we lose all visual information we can still make mental representations, or "mental maps" of our surroundings. Even blind individuals compare with those who can see in tasks such as recreating large scale representations of their surroundings. We depend on external cues for navigation, but the effectiveness of mental maps contributes what we consider "good" navigators. Do you ever get lost going to a restaurant that you have been to before? Much like driving a car with a GPS onboard, using a map -- mental or physical -- will help in arriving at a specific location faster than just looking out the windows. Francesca Fortenbaugh and colleagues explored the effectiveness of using mental maps in navigation by studying goal directed walking -- a procedure in which subjects are told to find their through a course to a certain target.
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Posted by Aaron Couch at 9:54 AM • Comments (8)
April 12, 2007
Category: Development / Aging • Memory • Reasoning • Research
Cognitive decline as we age is all over the news lately. "Brain fitness" products are available for cell phones, Game Boys, and Xboxes, all designed to prevent the natural decline in cognitive ability as we age. There's even a significant body of work suggesting that this sort of product really can work.
But some of the brain games can be dull, repetitive work: memory tasks, number games, and optical illusions, while endlessly fascinating to cognitive scientists, might be less appealing to the general population.
Researchers Helga and Tony Noice believe that training in the theater arts has similar cognitive benefits, with the added benefit of actually being quite enjoyable to its participants. Together with Graham Staines, in 2004 they developed a controlled study to test their idea. They recruited 124 older adults, age 60 to 86, to participate in one of three study groups, by posting notices in senior centers in DuPage County, Illinois, offering a chance to participate in "arts training":
Ah, but which art? Will you be learning about painting landscapes, playing the oboe, reciting Shakespeare, or writing verse? Only those who sign up will find out.
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Posted by Dave Munger at 2:46 PM • Comments (11)
April 5, 2007
Category: Language • Memory • Research
Even though most of us aren't concerned with physical survival on a day-to-day basis, the concept of "survival" remains a potent one -- just think of the persistent success of TV shows like Survivor and Lost. Perhaps this popularity has to do with more than just good advertising and an interesting plot twist. Perhaps it also has to do with the fundamental nature of survival itself.
Darwin's mechanism for evolution -- natural selection -- has often been reduced to the catch-phrase "survival of the fittest." There's more to it than that, of course, but if survival is such an important aspect of evolution, then wouldn't it make sense that traits -- even TV show preferences -- that have to do with survival are more likely to be passed on to successive generations?
A team led by James Nairne used similar lines of thinking as the basis for an investigation of the nature of a different trait: memory. They reasoned that if the brain evolved for survival, then we might be more likely to remember words related to survival then other words. Three groups of volunteers were shown the same thirty words and asked to rate them on one of three different scales. The first group was told to imagine they needed to survive in the wild grasslands of a foreign country, and rate each word for how important it was to their survival. The second group imagined moving to a foreign country and buying a house there, and rated each word on its importance for the move. The final group just rated the words for pleasantness.
The ratings were actually just a means of keeping the readers focused on the words in a particular context -- either survival-related or not survival-related. The key came at the end of the rating session. Now volunteers were surprised with a memory task: they had to write down as many of the words they could remember from the rating session. Here are the results:
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Posted by Dave Munger at 3:23 PM • Comments (9)
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