Perception
dmunger | December 15, 2008When I was 12 years old, I sometimes got to ride the train from Seattle to my aunt's house in Portland. Staring at the countryside flashing past the train window, it seemed to me that the landscape was rotating in a giant circle: Nearby objects flashed past the train as expected -- they appeared to move the opposite way the train was going. But the mountains in the distance seemed to be moving forward, faster than the train. It was as if the land next to us was just a vast turntable, rotating rapidly as we stayed in the same place. This video (not my own) captures some of the effect:
I knew…
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…
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…
edyong | December 2, 2008A ridiculous number of science-fiction TV series and films have moments where characters exchange minds, from the brilliance of Quantum Leap to the latest season of Heroes. Body-swapping is such a staple of imaginative fiction that it's tempting to think that it has no place being scientifically investigated. But Valeria Petkova and Henrik Ehrsson beg to differ - while actually exchanging minds is clearly impossible, these two scientists have created an illusion that can make people feel that another body - be it a mannequin or an actual person - is really theirs.
The idea that our bodies…
dmunger | December 2, 2008We can quickly spot a face staring at us in a crowd. We can do this much quicker, for example, than we can determine that no one is staring at us, as this movie demonstrates. A grid of 100 pictures of Greta will be flashed for about 1/3 of a second. Can you spot the photos where she's looking at you? You'll see two different grids.
Most people are able to detect the staring faces much faster than those looking to the side. But we can also sometimes be fooled by faces, something we discussed on one of the first-ever CogDaily posts:
In this picture, the eyes for each face are exactly the…
edyong | November 27, 2008
It goes without saying that we are capable of noticing changes to our bodies, but it's perhaps less obvious that the way we perceive our bodies can affect them physically. The two-way nature of this link, between physicality and perception, has been dramatically demonstrated by a new study of people with chronic hand pain. Lorimer Moseley at the University of Oxford found that he could control the severity of pain and swelling in an aching hand by making it seem larger or smaller.
Moseley recruited 10 patients with chronic pain in one of their arms and asked them to perform a series of ten…
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.…
edyong | November 24, 2008Have you ever seen someone that you're sure you recognise but whose face you just can't seem to place? It's a common enough occurrence, but for some people, problems with recognising faces are a part of their daily lives. They have a condition called prosopagnosia, or face blindness, which makes them incredibly bad at recognising faces, despite their normal eyesight, memory, intelligence, and ability to recognise other objects.
Prosopagnosia can be caused by accidents that damage parts of the brain like the fusiform gyrus - the core part of a broad network of regions involved in processing…
dmunger | November 19, 2008A Necker cube is bi-stable figure, meaning that it can be perceived as two different three-dimensional objects, depending on how you look at it:
Cube A is ambiguous -- the true Necker cube. Cube B and cube C show the two ways you can perceive the Necker cube: either the bottom of the cube is in front, or the top is in front. What's interesting about figures such as the Necker cube is that once you're aware of its bi-stable nature, it's impossible to see it only one way. Don't believe me? Then take this challenge. Play the movie below (it lasts for two minutes). The figure will flash every…
dmunger | November 11, 2008Philosophers have wondered for centuries whether someone who was blind from birth would "see" the world in the same way as people with normal vision. After all, there's much more to perceiving the world than properly functioning eyes. Think of it: otherwise all you'd need to do is strap a camcorder to a car and you'd never have to learn how to drive!
But there are surprisingly few cases of people who were born completely blind and then had their sight restored after many years of blindness. If a patient can be cured, it's usually done quite early in life. But a few cases have emerged in…
dmunger | November 5, 2008I play soccer every week with an ever-changing group of people. We're all busy, and people get injured or lose interest, so every week the crowd is slightly different; it often feels like we need to re-acquaint ourselves before every game. The easiest way to do this is during warm-ups when small groups kick the ball around in a circle or take practice shots on goal.
If you arrive a little late, you might have to insinuate yourself into one of the groups by strolling up and hoping someone passes you the ball. Typically this is pretty easy, but if the others are engaged in conversation, they…
dmunger | October 30, 2008Carmen Miranda is probably best-known today as the former spokesperson for Chiquita bananas, but she was equally famous -- and outrageous -- as an actress, singer, and dancer in the 1940s and 1950s.
Cognitive dissonance is a psychological phenomenon that occurs when people's actions contradict strongly-held beliefs. It's such a distasteful feeling that people will often invent convoluted justifications to account for their actions. For example, if a white employer who believes herself not to be a racist decides not to hire an African American job applicant, she might justify her decision by…
dmunger | October 14, 2008Yesterday we tried to replicate the effect that John Eastwood, Daniel Smilek, and Philip Merikle observed -- that negative facial expressions distract us from even the simplest tasks more than positive facial expressions. Hundreds of our readers watched one of two videos and were charged with counting the number of "upturned arcs" or "downturned arcs." Here's a sample video:
In this video, the "faces" formed by the arcs are smiling, but in the other video they were frowning. Both clips showed the identical number of upturned and downturned arcs -- six. Yet we weren't able to replicate…
dmunger | October 13, 2008Here's a really interesting experiment that we may be able to replicate online. Take a look at this very short video. You'll be shown a set of 12 arcs. Some of the arcs will be upturned and some of them will be turned downward, as in the example below.
You'll have about 2.5 seconds to count the DOWNTURNED arcs -- just watch the video once!
How many did you see? Record your answer below.
How many downturned arcs did you see (second try) ( polls)
After you've answered the poll, read on for an explanation of what this all means.
Just to make sure your answer isn't spoiled, I'm going to…
dmunger | October 9, 2008Take a look at this video:
You may have seen it before -- it's the work of a CGI animation studio that takes the motions of human actors and turns them into animated models, giving them the ability to put incredibly realistic figures in impossible situations, like on Mars, or swimming in lava, or whatever an animator can conceive of.
But the advent of realistic simulations such as this makes it clear that people need to be more aware than ever of the potential for digital fraud. We now have email spam, but in the future we might have similar computerized instant messaging spam, or even video…
dmunger | October 7, 2008When Sarah Palin was introduced to the country, most Americans had never heard of her -- but many people noticed that she looked very similar to the then-more-famous actor Tina Fey. Can you tell which is which?
Let's make this a poll:
Which one is Sarah Palin? ( polls)
We're amazingly good at recognizing the faces of friends and family members. We can even recognize people we know well by viewing point-light displays of them walking. But what about strangers? If we see the same person twice, do we remember them correctly? How accurate are we at determining whether a person matches the…
dmunger | September 24, 2008When Jimmy and Nora were toddlers, we bought them great little plastic scooters to ride around the house. They were the perfect size for a small child. Yet Jimmy preferred to ride around on a plastic garbage truck instead, despite the fact that there was no steering wheel and the "seat" wasn't nearly as comfortable, at least to our adult eyes:
We figured this behavior was just one of Jimmy's unique quirks. It didn't really bother us, except for the knowledge that we could have saved 20 bucks on the "real" scooter if we'd only known he would end up preferring the garbage truck.
In 2003, Judy…
edyong | September 16, 2008Our languages are replete with phrases that unite words evoking a sense of cold with concepts of loneliness, social exclusion or misanthropy. When we speak of icy stares, frosty receptions and cold shoulders, we invoke feelings of isolation and unfriendliness. But cold and solitude are more than just metaphorical bedfellows; a new study shows that social exclusion can literally make people feel cold.
Chen-Bo Zhong and Geoffrey Leonardelli from the University of Toronto recruited 65 students and were asked to recall a situation where they either felt included within a group or left out of it…
dmunger | September 8, 2008Take a look at these pictures.
Each picture depicts four shapes -- irregular vertical columns spanning the height of the picture. It's easy to tell which letter is on a column and which is not, right? If our readers are typical, over 90 percent would agree that a is on a column and b is not. But why? The space defined by the irregular vertical lines is equal in both cases. The only difference between the two figures is which direction the "pointy" curves face and which direction the convex, "smooth" curves face. Yet nearly everyone agrees that areas defined by the convex curves (like those…